xref: /freebsd/contrib/llvm-project/llvm/lib/Target/X86/MCTargetDesc/X86InstComments.cpp (revision 7877fdebeeb35fad1cbbafce22598b1bdf97c786) 
1 //===-- X86InstComments.cpp - Generate verbose-asm comments for instrs ----===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This defines functionality used to emit comments about X86 instructions to
10 // an output stream for -fverbose-asm.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "X86InstComments.h"
15 #include "X86ATTInstPrinter.h"
16 #include "X86BaseInfo.h"
17 #include "X86MCTargetDesc.h"
18 #include "X86ShuffleDecode.h"
19 #include "llvm/MC/MCInst.h"
20 #include "llvm/MC/MCInstrInfo.h"
21 #include "llvm/Support/raw_ostream.h"
22 
23 using namespace llvm;
24 
25 #define CASE_SSE_INS_COMMON(Inst, src)            \
26   case X86::Inst##src:
27 
28 #define CASE_AVX_INS_COMMON(Inst, Suffix, src)    \
29   case X86::V##Inst##Suffix##src:
30 
31 #define CASE_MASK_INS_COMMON(Inst, Suffix, src)   \
32   case X86::V##Inst##Suffix##src##k:
33 
34 #define CASE_MASKZ_INS_COMMON(Inst, Suffix, src)  \
35   case X86::V##Inst##Suffix##src##kz:
36 
37 #define CASE_AVX512_INS_COMMON(Inst, Suffix, src) \
38   CASE_AVX_INS_COMMON(Inst, Suffix, src)          \
39   CASE_MASK_INS_COMMON(Inst, Suffix, src)         \
40   CASE_MASKZ_INS_COMMON(Inst, Suffix, src)
41 
42 #define CASE_MOVDUP(Inst, src)                    \
43   CASE_AVX512_INS_COMMON(Inst, Z, r##src)         \
44   CASE_AVX512_INS_COMMON(Inst, Z256, r##src)      \
45   CASE_AVX512_INS_COMMON(Inst, Z128, r##src)      \
46   CASE_AVX_INS_COMMON(Inst, , r##src)             \
47   CASE_AVX_INS_COMMON(Inst, Y, r##src)            \
48   CASE_SSE_INS_COMMON(Inst, r##src)
49 
50 #define CASE_MASK_MOVDUP(Inst, src)               \
51   CASE_MASK_INS_COMMON(Inst, Z, r##src)           \
52   CASE_MASK_INS_COMMON(Inst, Z256, r##src)        \
53   CASE_MASK_INS_COMMON(Inst, Z128, r##src)
54 
55 #define CASE_MASKZ_MOVDUP(Inst, src)              \
56   CASE_MASKZ_INS_COMMON(Inst, Z, r##src)          \
57   CASE_MASKZ_INS_COMMON(Inst, Z256, r##src)       \
58   CASE_MASKZ_INS_COMMON(Inst, Z128, r##src)
59 
60 #define CASE_PMOVZX(Inst, src)                    \
61   CASE_AVX512_INS_COMMON(Inst, Z, r##src)         \
62   CASE_AVX512_INS_COMMON(Inst, Z256, r##src)      \
63   CASE_AVX512_INS_COMMON(Inst, Z128, r##src)      \
64   CASE_AVX_INS_COMMON(Inst, , r##src)             \
65   CASE_AVX_INS_COMMON(Inst, Y, r##src)            \
66   CASE_SSE_INS_COMMON(Inst, r##src)
67 
68 #define CASE_MASK_PMOVZX(Inst, src)               \
69   CASE_MASK_INS_COMMON(Inst, Z, r##src)           \
70   CASE_MASK_INS_COMMON(Inst, Z256, r##src)        \
71   CASE_MASK_INS_COMMON(Inst, Z128, r##src)
72 
73 #define CASE_MASKZ_PMOVZX(Inst, src)              \
74   CASE_MASKZ_INS_COMMON(Inst, Z, r##src)          \
75   CASE_MASKZ_INS_COMMON(Inst, Z256, r##src)       \
76   CASE_MASKZ_INS_COMMON(Inst, Z128, r##src)
77 
78 #define CASE_UNPCK(Inst, src)                     \
79   CASE_AVX512_INS_COMMON(Inst, Z, r##src)         \
80   CASE_AVX512_INS_COMMON(Inst, Z256, r##src)      \
81   CASE_AVX512_INS_COMMON(Inst, Z128, r##src)      \
82   CASE_AVX_INS_COMMON(Inst, , r##src)             \
83   CASE_AVX_INS_COMMON(Inst, Y, r##src)            \
84   CASE_SSE_INS_COMMON(Inst, r##src)
85 
86 #define CASE_MASK_UNPCK(Inst, src)                \
87   CASE_MASK_INS_COMMON(Inst, Z, r##src)           \
88   CASE_MASK_INS_COMMON(Inst, Z256, r##src)        \
89   CASE_MASK_INS_COMMON(Inst, Z128, r##src)
90 
91 #define CASE_MASKZ_UNPCK(Inst, src)               \
92   CASE_MASKZ_INS_COMMON(Inst, Z, r##src)          \
93   CASE_MASKZ_INS_COMMON(Inst, Z256, r##src)       \
94   CASE_MASKZ_INS_COMMON(Inst, Z128, r##src)
95 
96 #define CASE_SHUF(Inst, suf)                      \
97   CASE_AVX512_INS_COMMON(Inst, Z, suf)            \
98   CASE_AVX512_INS_COMMON(Inst, Z256, suf)         \
99   CASE_AVX512_INS_COMMON(Inst, Z128, suf)         \
100   CASE_AVX_INS_COMMON(Inst, , suf)                \
101   CASE_AVX_INS_COMMON(Inst, Y, suf)               \
102   CASE_SSE_INS_COMMON(Inst, suf)
103 
104 #define CASE_MASK_SHUF(Inst, src)                 \
105   CASE_MASK_INS_COMMON(Inst, Z, r##src##i)        \
106   CASE_MASK_INS_COMMON(Inst, Z256, r##src##i)     \
107   CASE_MASK_INS_COMMON(Inst, Z128, r##src##i)
108 
109 #define CASE_MASKZ_SHUF(Inst, src)                \
110   CASE_MASKZ_INS_COMMON(Inst, Z, r##src##i)       \
111   CASE_MASKZ_INS_COMMON(Inst, Z256, r##src##i)    \
112   CASE_MASKZ_INS_COMMON(Inst, Z128, r##src##i)
113 
114 #define CASE_VPERMILPI(Inst, src)                 \
115   CASE_AVX512_INS_COMMON(Inst, Z, src##i)         \
116   CASE_AVX512_INS_COMMON(Inst, Z256, src##i)      \
117   CASE_AVX512_INS_COMMON(Inst, Z128, src##i)      \
118   CASE_AVX_INS_COMMON(Inst, , src##i)             \
119   CASE_AVX_INS_COMMON(Inst, Y, src##i)
120 
121 #define CASE_MASK_VPERMILPI(Inst, src)            \
122   CASE_MASK_INS_COMMON(Inst, Z, src##i)           \
123   CASE_MASK_INS_COMMON(Inst, Z256, src##i)        \
124   CASE_MASK_INS_COMMON(Inst, Z128, src##i)
125 
126 #define CASE_MASKZ_VPERMILPI(Inst, src)           \
127   CASE_MASKZ_INS_COMMON(Inst, Z, src##i)          \
128   CASE_MASKZ_INS_COMMON(Inst, Z256, src##i)       \
129   CASE_MASKZ_INS_COMMON(Inst, Z128, src##i)
130 
131 #define CASE_VPERM(Inst, src)                     \
132   CASE_AVX512_INS_COMMON(Inst, Z, src##i)         \
133   CASE_AVX512_INS_COMMON(Inst, Z256, src##i)      \
134   CASE_AVX_INS_COMMON(Inst, Y, src##i)
135 
136 #define CASE_MASK_VPERM(Inst, src)                \
137   CASE_MASK_INS_COMMON(Inst, Z, src##i)           \
138   CASE_MASK_INS_COMMON(Inst, Z256, src##i)
139 
140 #define CASE_MASKZ_VPERM(Inst, src)               \
141   CASE_MASKZ_INS_COMMON(Inst, Z, src##i)          \
142   CASE_MASKZ_INS_COMMON(Inst, Z256, src##i)
143 
144 #define CASE_VSHUF(Inst, src)                          \
145   CASE_AVX512_INS_COMMON(SHUFF##Inst, Z, r##src##i)    \
146   CASE_AVX512_INS_COMMON(SHUFI##Inst, Z, r##src##i)    \
147   CASE_AVX512_INS_COMMON(SHUFF##Inst, Z256, r##src##i) \
148   CASE_AVX512_INS_COMMON(SHUFI##Inst, Z256, r##src##i)
149 
150 #define CASE_MASK_VSHUF(Inst, src)                    \
151   CASE_MASK_INS_COMMON(SHUFF##Inst, Z, r##src##i)     \
152   CASE_MASK_INS_COMMON(SHUFI##Inst, Z, r##src##i)     \
153   CASE_MASK_INS_COMMON(SHUFF##Inst, Z256, r##src##i)  \
154   CASE_MASK_INS_COMMON(SHUFI##Inst, Z256, r##src##i)
155 
156 #define CASE_MASKZ_VSHUF(Inst, src)                   \
157   CASE_MASKZ_INS_COMMON(SHUFF##Inst, Z, r##src##i)    \
158   CASE_MASKZ_INS_COMMON(SHUFI##Inst, Z, r##src##i)    \
159   CASE_MASKZ_INS_COMMON(SHUFF##Inst, Z256, r##src##i) \
160   CASE_MASKZ_INS_COMMON(SHUFI##Inst, Z256, r##src##i)
161 
162 #define CASE_AVX512_FMA(Inst, suf)                \
163   CASE_AVX512_INS_COMMON(Inst, Z, suf)            \
164   CASE_AVX512_INS_COMMON(Inst, Z256, suf)         \
165   CASE_AVX512_INS_COMMON(Inst, Z128, suf)
166 
167 #define CASE_FMA(Inst, suf)                       \
168   CASE_AVX512_FMA(Inst, suf)                      \
169   CASE_AVX_INS_COMMON(Inst, , suf)                \
170   CASE_AVX_INS_COMMON(Inst, Y, suf)
171 
172 #define CASE_FMA_PACKED_REG(Inst)                 \
173   CASE_FMA(Inst##PD, r)                           \
174   CASE_FMA(Inst##PS, r)
175 
176 #define CASE_FMA_PACKED_MEM(Inst)                 \
177   CASE_FMA(Inst##PD, m)                           \
178   CASE_FMA(Inst##PS, m)                           \
179   CASE_AVX512_FMA(Inst##PD, mb)                   \
180   CASE_AVX512_FMA(Inst##PS, mb)
181 
182 #define CASE_FMA_SCALAR_REG(Inst)                 \
183   CASE_AVX_INS_COMMON(Inst##SD, , r)              \
184   CASE_AVX_INS_COMMON(Inst##SS, , r)              \
185   CASE_AVX_INS_COMMON(Inst##SD, , r_Int)          \
186   CASE_AVX_INS_COMMON(Inst##SS, , r_Int)          \
187   CASE_AVX_INS_COMMON(Inst##SD, Z, r)             \
188   CASE_AVX_INS_COMMON(Inst##SS, Z, r)             \
189   CASE_AVX512_INS_COMMON(Inst##SD, Z, r_Int)      \
190   CASE_AVX512_INS_COMMON(Inst##SS, Z, r_Int)
191 
192 #define CASE_FMA_SCALAR_MEM(Inst)                 \
193   CASE_AVX_INS_COMMON(Inst##SD, , m)              \
194   CASE_AVX_INS_COMMON(Inst##SS, , m)              \
195   CASE_AVX_INS_COMMON(Inst##SD, , m_Int)          \
196   CASE_AVX_INS_COMMON(Inst##SS, , m_Int)          \
197   CASE_AVX_INS_COMMON(Inst##SD, Z, m)             \
198   CASE_AVX_INS_COMMON(Inst##SS, Z, m)             \
199   CASE_AVX512_INS_COMMON(Inst##SD, Z, m_Int)      \
200   CASE_AVX512_INS_COMMON(Inst##SS, Z, m_Int)
201 
202 #define CASE_FMA4(Inst, suf)                      \
203   CASE_AVX_INS_COMMON(Inst, 4, suf)               \
204   CASE_AVX_INS_COMMON(Inst, 4Y, suf)
205 
206 #define CASE_FMA4_PACKED_RR(Inst)                 \
207   CASE_FMA4(Inst##PD, rr)                         \
208   CASE_FMA4(Inst##PS, rr)
209 
210 #define CASE_FMA4_PACKED_RM(Inst)                 \
211   CASE_FMA4(Inst##PD, rm)                         \
212   CASE_FMA4(Inst##PS, rm)
213 
214 #define CASE_FMA4_PACKED_MR(Inst)                 \
215   CASE_FMA4(Inst##PD, mr)                         \
216   CASE_FMA4(Inst##PS, mr)
217 
218 #define CASE_FMA4_SCALAR_RR(Inst)                 \
219   CASE_AVX_INS_COMMON(Inst##SD4, , rr)            \
220   CASE_AVX_INS_COMMON(Inst##SS4, , rr)            \
221   CASE_AVX_INS_COMMON(Inst##SD4, , rr_Int)        \
222   CASE_AVX_INS_COMMON(Inst##SS4, , rr_Int)
223 
224 #define CASE_FMA4_SCALAR_RM(Inst)                 \
225   CASE_AVX_INS_COMMON(Inst##SD4, , rm)            \
226   CASE_AVX_INS_COMMON(Inst##SS4, , rm)            \
227   CASE_AVX_INS_COMMON(Inst##SD4, , rm_Int)        \
228   CASE_AVX_INS_COMMON(Inst##SS4, , rm_Int)
229 
230 #define CASE_FMA4_SCALAR_MR(Inst)                 \
231   CASE_AVX_INS_COMMON(Inst##SD4, , mr)            \
232   CASE_AVX_INS_COMMON(Inst##SS4, , mr)            \
233   CASE_AVX_INS_COMMON(Inst##SD4, , mr_Int)        \
234   CASE_AVX_INS_COMMON(Inst##SS4, , mr_Int)
235 
236 static unsigned getVectorRegSize(unsigned RegNo) {
237   if (X86::ZMM0 <= RegNo && RegNo <= X86::ZMM31)
238     return 512;
239   if (X86::YMM0 <= RegNo && RegNo <= X86::YMM31)
240     return 256;
241   if (X86::XMM0 <= RegNo && RegNo <= X86::XMM31)
242     return 128;
243   if (X86::MM0 <= RegNo && RegNo <= X86::MM7)
244     return 64;
245 
246   llvm_unreachable("Unknown vector reg!");
247 }
248 
249 static unsigned getRegOperandNumElts(const MCInst *MI, unsigned ScalarSize,
250                                      unsigned OperandIndex) {
251   unsigned OpReg = MI->getOperand(OperandIndex).getReg();
252   return getVectorRegSize(OpReg) / ScalarSize;
253 }
254 
255 static const char *getRegName(unsigned Reg) {
256   return X86ATTInstPrinter::getRegisterName(Reg);
257 }
258 
259 /// Wraps the destination register name with AVX512 mask/maskz filtering.
260 static void printMasking(raw_ostream &OS, const MCInst *MI,
261                          const MCInstrInfo &MCII) {
262   const MCInstrDesc &Desc = MCII.get(MI->getOpcode());
263   uint64_t TSFlags = Desc.TSFlags;
264 
265   if (!(TSFlags & X86II::EVEX_K))
266     return;
267 
268   bool MaskWithZero = (TSFlags & X86II::EVEX_Z);
269   unsigned MaskOp = Desc.getNumDefs();
270 
271   if (Desc.getOperandConstraint(MaskOp, MCOI::TIED_TO) != -1)
272     ++MaskOp;
273 
274   const char *MaskRegName = getRegName(MI->getOperand(MaskOp).getReg());
275 
276   // MASK: zmmX {%kY}
277   OS << " {%" << MaskRegName << "}";
278 
279   // MASKZ: zmmX {%kY} {z}
280   if (MaskWithZero)
281     OS << " {z}";
282 }
283 
284 static bool printFMAComments(const MCInst *MI, raw_ostream &OS,
285                              const MCInstrInfo &MCII) {
286   const char *Mul1Name = nullptr, *Mul2Name = nullptr, *AccName = nullptr;
287   unsigned NumOperands = MI->getNumOperands();
288   bool RegForm = false;
289   bool Negate = false;
290   StringRef AccStr = "+";
291 
292   // The operands for FMA3 instructions without rounding fall into two forms:
293   //  dest, src1, src2, src3
294   //  dest, src1, mask, src2, src3
295   // Where src3 is either a register or 5 memory address operands. So to find
296   // dest and src1 we can index from the front. To find src2 and src3 we can
297   // index from the end by taking into account memory vs register form when
298   // finding src2.
299 
300   // The operands for FMA4 instructions:
301   //  dest, src1, src2, src3
302   // Where src2 OR src3 are either a register or 5 memory address operands. So
303   // to find dest and src1 we can index from the front, src2 (reg/mem) follows
304   // and then src3 (reg) will be at the end.
305 
306   switch (MI->getOpcode()) {
307   default:
308     return false;
309 
310   CASE_FMA4_PACKED_RR(FMADD)
311   CASE_FMA4_SCALAR_RR(FMADD)
312     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
313     LLVM_FALLTHROUGH;
314   CASE_FMA4_PACKED_RM(FMADD)
315   CASE_FMA4_SCALAR_RM(FMADD)
316     Mul2Name = getRegName(MI->getOperand(2).getReg());
317     Mul1Name = getRegName(MI->getOperand(1).getReg());
318     break;
319   CASE_FMA4_PACKED_MR(FMADD)
320   CASE_FMA4_SCALAR_MR(FMADD)
321     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
322     Mul1Name = getRegName(MI->getOperand(1).getReg());
323     break;
324 
325   CASE_FMA4_PACKED_RR(FMSUB)
326   CASE_FMA4_SCALAR_RR(FMSUB)
327     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
328     LLVM_FALLTHROUGH;
329   CASE_FMA4_PACKED_RM(FMSUB)
330   CASE_FMA4_SCALAR_RM(FMSUB)
331     Mul2Name = getRegName(MI->getOperand(2).getReg());
332     Mul1Name = getRegName(MI->getOperand(1).getReg());
333     AccStr = "-";
334     break;
335   CASE_FMA4_PACKED_MR(FMSUB)
336   CASE_FMA4_SCALAR_MR(FMSUB)
337     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
338     Mul1Name = getRegName(MI->getOperand(1).getReg());
339     AccStr = "-";
340     break;
341 
342   CASE_FMA4_PACKED_RR(FNMADD)
343   CASE_FMA4_SCALAR_RR(FNMADD)
344     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
345     LLVM_FALLTHROUGH;
346   CASE_FMA4_PACKED_RM(FNMADD)
347   CASE_FMA4_SCALAR_RM(FNMADD)
348     Mul2Name = getRegName(MI->getOperand(2).getReg());
349     Mul1Name = getRegName(MI->getOperand(1).getReg());
350     Negate = true;
351     break;
352   CASE_FMA4_PACKED_MR(FNMADD)
353   CASE_FMA4_SCALAR_MR(FNMADD)
354     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
355     Mul1Name = getRegName(MI->getOperand(1).getReg());
356     Negate = true;
357     break;
358 
359   CASE_FMA4_PACKED_RR(FNMSUB)
360   CASE_FMA4_SCALAR_RR(FNMSUB)
361     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
362     LLVM_FALLTHROUGH;
363   CASE_FMA4_PACKED_RM(FNMSUB)
364   CASE_FMA4_SCALAR_RM(FNMSUB)
365     Mul2Name = getRegName(MI->getOperand(2).getReg());
366     Mul1Name = getRegName(MI->getOperand(1).getReg());
367     AccStr = "-";
368     Negate = true;
369     break;
370   CASE_FMA4_PACKED_MR(FNMSUB)
371   CASE_FMA4_SCALAR_MR(FNMSUB)
372     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
373     Mul1Name = getRegName(MI->getOperand(1).getReg());
374     AccStr = "-";
375     Negate = true;
376     break;
377 
378   CASE_FMA4_PACKED_RR(FMADDSUB)
379     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
380     LLVM_FALLTHROUGH;
381   CASE_FMA4_PACKED_RM(FMADDSUB)
382     Mul2Name = getRegName(MI->getOperand(2).getReg());
383     Mul1Name = getRegName(MI->getOperand(1).getReg());
384     AccStr = "+/-";
385     break;
386   CASE_FMA4_PACKED_MR(FMADDSUB)
387     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
388     Mul1Name = getRegName(MI->getOperand(1).getReg());
389     AccStr = "+/-";
390     break;
391 
392   CASE_FMA4_PACKED_RR(FMSUBADD)
393     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
394     LLVM_FALLTHROUGH;
395   CASE_FMA4_PACKED_RM(FMSUBADD)
396     Mul2Name = getRegName(MI->getOperand(2).getReg());
397     Mul1Name = getRegName(MI->getOperand(1).getReg());
398     AccStr = "-/+";
399     break;
400   CASE_FMA4_PACKED_MR(FMSUBADD)
401     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
402     Mul1Name = getRegName(MI->getOperand(1).getReg());
403     AccStr = "-/+";
404     break;
405 
406   CASE_FMA_PACKED_REG(FMADD132)
407   CASE_FMA_SCALAR_REG(FMADD132)
408     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
409     RegForm = true;
410     LLVM_FALLTHROUGH;
411   CASE_FMA_PACKED_MEM(FMADD132)
412   CASE_FMA_SCALAR_MEM(FMADD132)
413     AccName = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
414     Mul1Name = getRegName(MI->getOperand(1).getReg());
415     break;
416 
417   CASE_FMA_PACKED_REG(FMADD213)
418   CASE_FMA_SCALAR_REG(FMADD213)
419     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
420     RegForm = true;
421     LLVM_FALLTHROUGH;
422   CASE_FMA_PACKED_MEM(FMADD213)
423   CASE_FMA_SCALAR_MEM(FMADD213)
424     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
425     Mul2Name = getRegName(MI->getOperand(1).getReg());
426     break;
427 
428   CASE_FMA_PACKED_REG(FMADD231)
429   CASE_FMA_SCALAR_REG(FMADD231)
430     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
431     RegForm = true;
432     LLVM_FALLTHROUGH;
433   CASE_FMA_PACKED_MEM(FMADD231)
434   CASE_FMA_SCALAR_MEM(FMADD231)
435     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
436     AccName = getRegName(MI->getOperand(1).getReg());
437     break;
438 
439   CASE_FMA_PACKED_REG(FMSUB132)
440   CASE_FMA_SCALAR_REG(FMSUB132)
441     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
442     RegForm = true;
443     LLVM_FALLTHROUGH;
444   CASE_FMA_PACKED_MEM(FMSUB132)
445   CASE_FMA_SCALAR_MEM(FMSUB132)
446     AccName = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
447     Mul1Name = getRegName(MI->getOperand(1).getReg());
448     AccStr = "-";
449     break;
450 
451   CASE_FMA_PACKED_REG(FMSUB213)
452   CASE_FMA_SCALAR_REG(FMSUB213)
453     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
454     RegForm = true;
455     LLVM_FALLTHROUGH;
456   CASE_FMA_PACKED_MEM(FMSUB213)
457   CASE_FMA_SCALAR_MEM(FMSUB213)
458     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
459     Mul2Name = getRegName(MI->getOperand(1).getReg());
460     AccStr = "-";
461     break;
462 
463   CASE_FMA_PACKED_REG(FMSUB231)
464   CASE_FMA_SCALAR_REG(FMSUB231)
465     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
466     RegForm = true;
467     LLVM_FALLTHROUGH;
468   CASE_FMA_PACKED_MEM(FMSUB231)
469   CASE_FMA_SCALAR_MEM(FMSUB231)
470     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
471     AccName = getRegName(MI->getOperand(1).getReg());
472     AccStr = "-";
473     break;
474 
475   CASE_FMA_PACKED_REG(FNMADD132)
476   CASE_FMA_SCALAR_REG(FNMADD132)
477     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
478     RegForm = true;
479     LLVM_FALLTHROUGH;
480   CASE_FMA_PACKED_MEM(FNMADD132)
481   CASE_FMA_SCALAR_MEM(FNMADD132)
482     AccName = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
483     Mul1Name = getRegName(MI->getOperand(1).getReg());
484     Negate = true;
485     break;
486 
487   CASE_FMA_PACKED_REG(FNMADD213)
488   CASE_FMA_SCALAR_REG(FNMADD213)
489     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
490     RegForm = true;
491     LLVM_FALLTHROUGH;
492   CASE_FMA_PACKED_MEM(FNMADD213)
493   CASE_FMA_SCALAR_MEM(FNMADD213)
494     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
495     Mul2Name = getRegName(MI->getOperand(1).getReg());
496     Negate = true;
497     break;
498 
499   CASE_FMA_PACKED_REG(FNMADD231)
500   CASE_FMA_SCALAR_REG(FNMADD231)
501     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
502     RegForm = true;
503     LLVM_FALLTHROUGH;
504   CASE_FMA_PACKED_MEM(FNMADD231)
505   CASE_FMA_SCALAR_MEM(FNMADD231)
506     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
507     AccName = getRegName(MI->getOperand(1).getReg());
508     Negate = true;
509     break;
510 
511   CASE_FMA_PACKED_REG(FNMSUB132)
512   CASE_FMA_SCALAR_REG(FNMSUB132)
513     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
514     RegForm = true;
515     LLVM_FALLTHROUGH;
516   CASE_FMA_PACKED_MEM(FNMSUB132)
517   CASE_FMA_SCALAR_MEM(FNMSUB132)
518     AccName = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
519     Mul1Name = getRegName(MI->getOperand(1).getReg());
520     AccStr = "-";
521     Negate = true;
522     break;
523 
524   CASE_FMA_PACKED_REG(FNMSUB213)
525   CASE_FMA_SCALAR_REG(FNMSUB213)
526     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
527     RegForm = true;
528     LLVM_FALLTHROUGH;
529   CASE_FMA_PACKED_MEM(FNMSUB213)
530   CASE_FMA_SCALAR_MEM(FNMSUB213)
531     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
532     Mul2Name = getRegName(MI->getOperand(1).getReg());
533     AccStr = "-";
534     Negate = true;
535     break;
536 
537   CASE_FMA_PACKED_REG(FNMSUB231)
538   CASE_FMA_SCALAR_REG(FNMSUB231)
539     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
540     RegForm = true;
541     LLVM_FALLTHROUGH;
542   CASE_FMA_PACKED_MEM(FNMSUB231)
543   CASE_FMA_SCALAR_MEM(FNMSUB231)
544     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
545     AccName = getRegName(MI->getOperand(1).getReg());
546     AccStr = "-";
547     Negate = true;
548     break;
549 
550   CASE_FMA_PACKED_REG(FMADDSUB132)
551     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
552     RegForm = true;
553     LLVM_FALLTHROUGH;
554   CASE_FMA_PACKED_MEM(FMADDSUB132)
555     AccName = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
556     Mul1Name = getRegName(MI->getOperand(1).getReg());
557     AccStr = "+/-";
558     break;
559 
560   CASE_FMA_PACKED_REG(FMADDSUB213)
561     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
562     RegForm = true;
563     LLVM_FALLTHROUGH;
564   CASE_FMA_PACKED_MEM(FMADDSUB213)
565     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
566     Mul2Name = getRegName(MI->getOperand(1).getReg());
567     AccStr = "+/-";
568     break;
569 
570   CASE_FMA_PACKED_REG(FMADDSUB231)
571     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
572     RegForm = true;
573     LLVM_FALLTHROUGH;
574   CASE_FMA_PACKED_MEM(FMADDSUB231)
575     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
576     AccName = getRegName(MI->getOperand(1).getReg());
577     AccStr = "+/-";
578     break;
579 
580   CASE_FMA_PACKED_REG(FMSUBADD132)
581     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
582     RegForm = true;
583     LLVM_FALLTHROUGH;
584   CASE_FMA_PACKED_MEM(FMSUBADD132)
585     AccName = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
586     Mul1Name = getRegName(MI->getOperand(1).getReg());
587     AccStr = "-/+";
588     break;
589 
590   CASE_FMA_PACKED_REG(FMSUBADD213)
591     AccName = getRegName(MI->getOperand(NumOperands - 1).getReg());
592     RegForm = true;
593     LLVM_FALLTHROUGH;
594   CASE_FMA_PACKED_MEM(FMSUBADD213)
595     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
596     Mul2Name = getRegName(MI->getOperand(1).getReg());
597     AccStr = "-/+";
598     break;
599 
600   CASE_FMA_PACKED_REG(FMSUBADD231)
601     Mul2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
602     RegForm = true;
603     LLVM_FALLTHROUGH;
604   CASE_FMA_PACKED_MEM(FMSUBADD231)
605     Mul1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
606     AccName = getRegName(MI->getOperand(1).getReg());
607     AccStr = "-/+";
608     break;
609   }
610 
611   const char *DestName = getRegName(MI->getOperand(0).getReg());
612 
613   if (!Mul1Name) Mul1Name = "mem";
614   if (!Mul2Name) Mul2Name = "mem";
615   if (!AccName)  AccName = "mem";
616 
617   OS << DestName;
618   printMasking(OS, MI, MCII);
619   OS << " = ";
620 
621   if (Negate)
622     OS << '-';
623 
624   OS << '(' << Mul1Name << " * " << Mul2Name << ") " << AccStr << ' '
625      << AccName;
626 
627   return true;
628 }
629 
630 
631 //===----------------------------------------------------------------------===//
632 // Top Level Entrypoint
633 //===----------------------------------------------------------------------===//
634 
635 /// EmitAnyX86InstComments - This function decodes x86 instructions and prints
636 /// newline terminated strings to the specified string if desired.  This
637 /// information is shown in disassembly dumps when verbose assembly is enabled.
638 bool llvm::EmitAnyX86InstComments(const MCInst *MI, raw_ostream &OS,
639                                   const MCInstrInfo &MCII) {
640   // If this is a shuffle operation, the switch should fill in this state.
641   SmallVector<int, 8> ShuffleMask;
642   const char *DestName = nullptr, *Src1Name = nullptr, *Src2Name = nullptr;
643   unsigned NumOperands = MI->getNumOperands();
644   bool RegForm = false;
645 
646   if (printFMAComments(MI, OS, MCII))
647     return true;
648 
649   switch (MI->getOpcode()) {
650   default:
651     // Not an instruction for which we can decode comments.
652     return false;
653 
654   case X86::BLENDPDrri:
655   case X86::VBLENDPDrri:
656   case X86::VBLENDPDYrri:
657     Src2Name = getRegName(MI->getOperand(2).getReg());
658     LLVM_FALLTHROUGH;
659   case X86::BLENDPDrmi:
660   case X86::VBLENDPDrmi:
661   case X86::VBLENDPDYrmi:
662     if (MI->getOperand(NumOperands - 1).isImm())
663       DecodeBLENDMask(getRegOperandNumElts(MI, 64, 0),
664                       MI->getOperand(NumOperands - 1).getImm(),
665                       ShuffleMask);
666     Src1Name = getRegName(MI->getOperand(1).getReg());
667     DestName = getRegName(MI->getOperand(0).getReg());
668     break;
669 
670   case X86::BLENDPSrri:
671   case X86::VBLENDPSrri:
672   case X86::VBLENDPSYrri:
673     Src2Name = getRegName(MI->getOperand(2).getReg());
674     LLVM_FALLTHROUGH;
675   case X86::BLENDPSrmi:
676   case X86::VBLENDPSrmi:
677   case X86::VBLENDPSYrmi:
678     if (MI->getOperand(NumOperands - 1).isImm())
679       DecodeBLENDMask(getRegOperandNumElts(MI, 32, 0),
680                       MI->getOperand(NumOperands - 1).getImm(),
681                       ShuffleMask);
682     Src1Name = getRegName(MI->getOperand(1).getReg());
683     DestName = getRegName(MI->getOperand(0).getReg());
684     break;
685 
686   case X86::PBLENDWrri:
687   case X86::VPBLENDWrri:
688   case X86::VPBLENDWYrri:
689     Src2Name = getRegName(MI->getOperand(2).getReg());
690     LLVM_FALLTHROUGH;
691   case X86::PBLENDWrmi:
692   case X86::VPBLENDWrmi:
693   case X86::VPBLENDWYrmi:
694     if (MI->getOperand(NumOperands - 1).isImm())
695       DecodeBLENDMask(getRegOperandNumElts(MI, 16, 0),
696                       MI->getOperand(NumOperands - 1).getImm(),
697                       ShuffleMask);
698     Src1Name = getRegName(MI->getOperand(1).getReg());
699     DestName = getRegName(MI->getOperand(0).getReg());
700     break;
701 
702   case X86::VPBLENDDrri:
703   case X86::VPBLENDDYrri:
704     Src2Name = getRegName(MI->getOperand(2).getReg());
705     LLVM_FALLTHROUGH;
706   case X86::VPBLENDDrmi:
707   case X86::VPBLENDDYrmi:
708     if (MI->getOperand(NumOperands - 1).isImm())
709       DecodeBLENDMask(getRegOperandNumElts(MI, 32, 0),
710                       MI->getOperand(NumOperands - 1).getImm(),
711                       ShuffleMask);
712     Src1Name = getRegName(MI->getOperand(1).getReg());
713     DestName = getRegName(MI->getOperand(0).getReg());
714     break;
715 
716   case X86::INSERTPSrr:
717   case X86::VINSERTPSrr:
718   case X86::VINSERTPSZrr:
719     Src2Name = getRegName(MI->getOperand(2).getReg());
720     LLVM_FALLTHROUGH;
721   case X86::INSERTPSrm:
722   case X86::VINSERTPSrm:
723   case X86::VINSERTPSZrm:
724     DestName = getRegName(MI->getOperand(0).getReg());
725     Src1Name = getRegName(MI->getOperand(1).getReg());
726     if (MI->getOperand(NumOperands - 1).isImm())
727       DecodeINSERTPSMask(MI->getOperand(NumOperands - 1).getImm(),
728                          ShuffleMask);
729     break;
730 
731   case X86::MOVLHPSrr:
732   case X86::VMOVLHPSrr:
733   case X86::VMOVLHPSZrr:
734     Src2Name = getRegName(MI->getOperand(2).getReg());
735     Src1Name = getRegName(MI->getOperand(1).getReg());
736     DestName = getRegName(MI->getOperand(0).getReg());
737     DecodeMOVLHPSMask(2, ShuffleMask);
738     break;
739 
740   case X86::MOVHLPSrr:
741   case X86::VMOVHLPSrr:
742   case X86::VMOVHLPSZrr:
743     Src2Name = getRegName(MI->getOperand(2).getReg());
744     Src1Name = getRegName(MI->getOperand(1).getReg());
745     DestName = getRegName(MI->getOperand(0).getReg());
746     DecodeMOVHLPSMask(2, ShuffleMask);
747     break;
748 
749   case X86::MOVHPDrm:
750   case X86::VMOVHPDrm:
751   case X86::VMOVHPDZ128rm:
752     Src1Name = getRegName(MI->getOperand(1).getReg());
753     DestName = getRegName(MI->getOperand(0).getReg());
754     DecodeInsertElementMask(2, 1, 1, ShuffleMask);
755     break;
756 
757   case X86::MOVHPSrm:
758   case X86::VMOVHPSrm:
759   case X86::VMOVHPSZ128rm:
760     Src1Name = getRegName(MI->getOperand(1).getReg());
761     DestName = getRegName(MI->getOperand(0).getReg());
762     DecodeInsertElementMask(4, 2, 2, ShuffleMask);
763     break;
764 
765   case X86::MOVLPDrm:
766   case X86::VMOVLPDrm:
767   case X86::VMOVLPDZ128rm:
768     Src1Name = getRegName(MI->getOperand(1).getReg());
769     DestName = getRegName(MI->getOperand(0).getReg());
770     DecodeInsertElementMask(2, 0, 1, ShuffleMask);
771     break;
772 
773   case X86::MOVLPSrm:
774   case X86::VMOVLPSrm:
775   case X86::VMOVLPSZ128rm:
776     Src1Name = getRegName(MI->getOperand(1).getReg());
777     DestName = getRegName(MI->getOperand(0).getReg());
778     DecodeInsertElementMask(4, 0, 2, ShuffleMask);
779     break;
780 
781   CASE_MOVDUP(MOVSLDUP, r)
782     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
783     LLVM_FALLTHROUGH;
784 
785   CASE_MOVDUP(MOVSLDUP, m)
786     DestName = getRegName(MI->getOperand(0).getReg());
787     DecodeMOVSLDUPMask(getRegOperandNumElts(MI, 32, 0), ShuffleMask);
788     break;
789 
790   CASE_MOVDUP(MOVSHDUP, r)
791     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
792     LLVM_FALLTHROUGH;
793 
794   CASE_MOVDUP(MOVSHDUP, m)
795     DestName = getRegName(MI->getOperand(0).getReg());
796     DecodeMOVSHDUPMask(getRegOperandNumElts(MI, 32, 0), ShuffleMask);
797     break;
798 
799   CASE_MOVDUP(MOVDDUP, r)
800     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
801     LLVM_FALLTHROUGH;
802 
803   CASE_MOVDUP(MOVDDUP, m)
804     DestName = getRegName(MI->getOperand(0).getReg());
805     DecodeMOVDDUPMask(getRegOperandNumElts(MI, 64, 0), ShuffleMask);
806     break;
807 
808   case X86::PSLLDQri:
809   case X86::VPSLLDQri:
810   case X86::VPSLLDQYri:
811   case X86::VPSLLDQZ128ri:
812   case X86::VPSLLDQZ256ri:
813   case X86::VPSLLDQZri:
814     Src1Name = getRegName(MI->getOperand(1).getReg());
815     LLVM_FALLTHROUGH;
816   case X86::VPSLLDQZ128mi:
817   case X86::VPSLLDQZ256mi:
818   case X86::VPSLLDQZmi:
819     DestName = getRegName(MI->getOperand(0).getReg());
820     if (MI->getOperand(NumOperands - 1).isImm())
821       DecodePSLLDQMask(getRegOperandNumElts(MI, 8, 0),
822                        MI->getOperand(NumOperands - 1).getImm(),
823                        ShuffleMask);
824     break;
825 
826   case X86::PSRLDQri:
827   case X86::VPSRLDQri:
828   case X86::VPSRLDQYri:
829   case X86::VPSRLDQZ128ri:
830   case X86::VPSRLDQZ256ri:
831   case X86::VPSRLDQZri:
832     Src1Name = getRegName(MI->getOperand(1).getReg());
833     LLVM_FALLTHROUGH;
834   case X86::VPSRLDQZ128mi:
835   case X86::VPSRLDQZ256mi:
836   case X86::VPSRLDQZmi:
837     DestName = getRegName(MI->getOperand(0).getReg());
838     if (MI->getOperand(NumOperands - 1).isImm())
839       DecodePSRLDQMask(getRegOperandNumElts(MI, 8, 0),
840                        MI->getOperand(NumOperands - 1).getImm(),
841                        ShuffleMask);
842     break;
843 
844   CASE_SHUF(PALIGNR, rri)
845     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
846     RegForm = true;
847     LLVM_FALLTHROUGH;
848 
849   CASE_SHUF(PALIGNR, rmi)
850     Src2Name = getRegName(MI->getOperand(NumOperands-(RegForm?3:7)).getReg());
851     DestName = getRegName(MI->getOperand(0).getReg());
852     if (MI->getOperand(NumOperands - 1).isImm())
853       DecodePALIGNRMask(getRegOperandNumElts(MI, 8, 0),
854                         MI->getOperand(NumOperands - 1).getImm(),
855                         ShuffleMask);
856     break;
857 
858   CASE_AVX512_INS_COMMON(ALIGNQ, Z, rri)
859   CASE_AVX512_INS_COMMON(ALIGNQ, Z256, rri)
860   CASE_AVX512_INS_COMMON(ALIGNQ, Z128, rri)
861     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
862     RegForm = true;
863     LLVM_FALLTHROUGH;
864 
865   CASE_AVX512_INS_COMMON(ALIGNQ, Z, rmi)
866   CASE_AVX512_INS_COMMON(ALIGNQ, Z256, rmi)
867   CASE_AVX512_INS_COMMON(ALIGNQ, Z128, rmi)
868     Src2Name = getRegName(MI->getOperand(NumOperands-(RegForm?3:7)).getReg());
869     DestName = getRegName(MI->getOperand(0).getReg());
870     if (MI->getOperand(NumOperands - 1).isImm())
871       DecodeVALIGNMask(getRegOperandNumElts(MI, 64, 0),
872                        MI->getOperand(NumOperands - 1).getImm(),
873                        ShuffleMask);
874     break;
875 
876   CASE_AVX512_INS_COMMON(ALIGND, Z, rri)
877   CASE_AVX512_INS_COMMON(ALIGND, Z256, rri)
878   CASE_AVX512_INS_COMMON(ALIGND, Z128, rri)
879     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
880     RegForm = true;
881     LLVM_FALLTHROUGH;
882 
883   CASE_AVX512_INS_COMMON(ALIGND, Z, rmi)
884   CASE_AVX512_INS_COMMON(ALIGND, Z256, rmi)
885   CASE_AVX512_INS_COMMON(ALIGND, Z128, rmi)
886     Src2Name = getRegName(MI->getOperand(NumOperands-(RegForm?3:7)).getReg());
887     DestName = getRegName(MI->getOperand(0).getReg());
888     if (MI->getOperand(NumOperands - 1).isImm())
889       DecodeVALIGNMask(getRegOperandNumElts(MI, 32, 0),
890                        MI->getOperand(NumOperands - 1).getImm(),
891                        ShuffleMask);
892     break;
893 
894   CASE_SHUF(PSHUFD, ri)
895     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
896     LLVM_FALLTHROUGH;
897 
898   CASE_SHUF(PSHUFD, mi)
899     DestName = getRegName(MI->getOperand(0).getReg());
900     if (MI->getOperand(NumOperands - 1).isImm())
901       DecodePSHUFMask(getRegOperandNumElts(MI, 32, 0), 32,
902                       MI->getOperand(NumOperands - 1).getImm(),
903                       ShuffleMask);
904     break;
905 
906   CASE_SHUF(PSHUFHW, ri)
907     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
908     LLVM_FALLTHROUGH;
909 
910   CASE_SHUF(PSHUFHW, mi)
911     DestName = getRegName(MI->getOperand(0).getReg());
912     if (MI->getOperand(NumOperands - 1).isImm())
913       DecodePSHUFHWMask(getRegOperandNumElts(MI, 16, 0),
914                         MI->getOperand(NumOperands - 1).getImm(),
915                         ShuffleMask);
916     break;
917 
918   CASE_SHUF(PSHUFLW, ri)
919     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
920     LLVM_FALLTHROUGH;
921 
922   CASE_SHUF(PSHUFLW, mi)
923     DestName = getRegName(MI->getOperand(0).getReg());
924     if (MI->getOperand(NumOperands - 1).isImm())
925       DecodePSHUFLWMask(getRegOperandNumElts(MI, 16, 0),
926                         MI->getOperand(NumOperands - 1).getImm(),
927                         ShuffleMask);
928     break;
929 
930   case X86::MMX_PSHUFWri:
931     Src1Name = getRegName(MI->getOperand(1).getReg());
932     LLVM_FALLTHROUGH;
933 
934   case X86::MMX_PSHUFWmi:
935     DestName = getRegName(MI->getOperand(0).getReg());
936     if (MI->getOperand(NumOperands - 1).isImm())
937       DecodePSHUFMask(4, 16, MI->getOperand(NumOperands - 1).getImm(),
938                       ShuffleMask);
939     break;
940 
941   case X86::PSWAPDrr:
942     Src1Name = getRegName(MI->getOperand(1).getReg());
943     LLVM_FALLTHROUGH;
944 
945   case X86::PSWAPDrm:
946     DestName = getRegName(MI->getOperand(0).getReg());
947     DecodePSWAPMask(2, ShuffleMask);
948     break;
949 
950   CASE_UNPCK(PUNPCKHBW, r)
951   case X86::MMX_PUNPCKHBWirr:
952     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
953     RegForm = true;
954     LLVM_FALLTHROUGH;
955 
956   CASE_UNPCK(PUNPCKHBW, m)
957   case X86::MMX_PUNPCKHBWirm:
958     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
959     DestName = getRegName(MI->getOperand(0).getReg());
960     DecodeUNPCKHMask(getRegOperandNumElts(MI, 8, 0), 8, ShuffleMask);
961     break;
962 
963   CASE_UNPCK(PUNPCKHWD, r)
964   case X86::MMX_PUNPCKHWDirr:
965     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
966     RegForm = true;
967     LLVM_FALLTHROUGH;
968 
969   CASE_UNPCK(PUNPCKHWD, m)
970   case X86::MMX_PUNPCKHWDirm:
971     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
972     DestName = getRegName(MI->getOperand(0).getReg());
973     DecodeUNPCKHMask(getRegOperandNumElts(MI, 16, 0), 16, ShuffleMask);
974     break;
975 
976   CASE_UNPCK(PUNPCKHDQ, r)
977   case X86::MMX_PUNPCKHDQirr:
978     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
979     RegForm = true;
980     LLVM_FALLTHROUGH;
981 
982   CASE_UNPCK(PUNPCKHDQ, m)
983   case X86::MMX_PUNPCKHDQirm:
984     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
985     DestName = getRegName(MI->getOperand(0).getReg());
986     DecodeUNPCKHMask(getRegOperandNumElts(MI, 32, 0), 32, ShuffleMask);
987     break;
988 
989   CASE_UNPCK(PUNPCKHQDQ, r)
990     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
991     RegForm = true;
992     LLVM_FALLTHROUGH;
993 
994   CASE_UNPCK(PUNPCKHQDQ, m)
995     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
996     DestName = getRegName(MI->getOperand(0).getReg());
997     DecodeUNPCKHMask(getRegOperandNumElts(MI, 64, 0), 64, ShuffleMask);
998     break;
999 
1000   CASE_UNPCK(PUNPCKLBW, r)
1001   case X86::MMX_PUNPCKLBWirr:
1002     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1003     RegForm = true;
1004     LLVM_FALLTHROUGH;
1005 
1006   CASE_UNPCK(PUNPCKLBW, m)
1007   case X86::MMX_PUNPCKLBWirm:
1008     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
1009     DestName = getRegName(MI->getOperand(0).getReg());
1010     DecodeUNPCKLMask(getRegOperandNumElts(MI, 8, 0), 8, ShuffleMask);
1011     break;
1012 
1013   CASE_UNPCK(PUNPCKLWD, r)
1014   case X86::MMX_PUNPCKLWDirr:
1015     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1016     RegForm = true;
1017     LLVM_FALLTHROUGH;
1018 
1019   CASE_UNPCK(PUNPCKLWD, m)
1020   case X86::MMX_PUNPCKLWDirm:
1021     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
1022     DestName = getRegName(MI->getOperand(0).getReg());
1023     DecodeUNPCKLMask(getRegOperandNumElts(MI, 16, 0), 16, ShuffleMask);
1024     break;
1025 
1026   CASE_UNPCK(PUNPCKLDQ, r)
1027   case X86::MMX_PUNPCKLDQirr:
1028     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1029     RegForm = true;
1030     LLVM_FALLTHROUGH;
1031 
1032   CASE_UNPCK(PUNPCKLDQ, m)
1033   case X86::MMX_PUNPCKLDQirm:
1034     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
1035     DestName = getRegName(MI->getOperand(0).getReg());
1036     DecodeUNPCKLMask(getRegOperandNumElts(MI, 32, 0), 32, ShuffleMask);
1037     break;
1038 
1039   CASE_UNPCK(PUNPCKLQDQ, r)
1040     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1041     RegForm = true;
1042     LLVM_FALLTHROUGH;
1043 
1044   CASE_UNPCK(PUNPCKLQDQ, m)
1045     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
1046     DestName = getRegName(MI->getOperand(0).getReg());
1047     DecodeUNPCKLMask(getRegOperandNumElts(MI, 64, 0), 64, ShuffleMask);
1048     break;
1049 
1050   CASE_SHUF(SHUFPD, rri)
1051     Src2Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
1052     RegForm = true;
1053     LLVM_FALLTHROUGH;
1054 
1055   CASE_SHUF(SHUFPD, rmi)
1056     if (MI->getOperand(NumOperands - 1).isImm())
1057       DecodeSHUFPMask(getRegOperandNumElts(MI, 64, 0), 64,
1058                       MI->getOperand(NumOperands - 1).getImm(), ShuffleMask);
1059     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?3:7)).getReg());
1060     DestName = getRegName(MI->getOperand(0).getReg());
1061     break;
1062 
1063   CASE_SHUF(SHUFPS, rri)
1064     Src2Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
1065     RegForm = true;
1066     LLVM_FALLTHROUGH;
1067 
1068   CASE_SHUF(SHUFPS, rmi)
1069     if (MI->getOperand(NumOperands - 1).isImm())
1070       DecodeSHUFPMask(getRegOperandNumElts(MI, 32, 0), 32,
1071                       MI->getOperand(NumOperands - 1).getImm(),
1072                       ShuffleMask);
1073     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?3:7)).getReg());
1074     DestName = getRegName(MI->getOperand(0).getReg());
1075     break;
1076 
1077   CASE_VSHUF(64X2, r)
1078     Src2Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
1079     RegForm = true;
1080     LLVM_FALLTHROUGH;
1081 
1082   CASE_VSHUF(64X2, m)
1083     decodeVSHUF64x2FamilyMask(getRegOperandNumElts(MI, 64, 0), 64,
1084                               MI->getOperand(NumOperands - 1).getImm(),
1085                               ShuffleMask);
1086     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?3:7)).getReg());
1087     DestName = getRegName(MI->getOperand(0).getReg());
1088     break;
1089 
1090   CASE_VSHUF(32X4, r)
1091     Src2Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
1092     RegForm = true;
1093     LLVM_FALLTHROUGH;
1094 
1095   CASE_VSHUF(32X4, m)
1096     decodeVSHUF64x2FamilyMask(getRegOperandNumElts(MI, 32, 0), 32,
1097                               MI->getOperand(NumOperands - 1).getImm(),
1098                               ShuffleMask);
1099     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?3:7)).getReg());
1100     DestName = getRegName(MI->getOperand(0).getReg());
1101     break;
1102 
1103   CASE_UNPCK(UNPCKLPD, r)
1104     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1105     RegForm = true;
1106     LLVM_FALLTHROUGH;
1107 
1108   CASE_UNPCK(UNPCKLPD, m)
1109     DecodeUNPCKLMask(getRegOperandNumElts(MI, 64, 0), 64, ShuffleMask);
1110     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
1111     DestName = getRegName(MI->getOperand(0).getReg());
1112     break;
1113 
1114   CASE_UNPCK(UNPCKLPS, r)
1115     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1116     RegForm = true;
1117     LLVM_FALLTHROUGH;
1118 
1119   CASE_UNPCK(UNPCKLPS, m)
1120     DecodeUNPCKLMask(getRegOperandNumElts(MI, 32, 0), 32, ShuffleMask);
1121     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
1122     DestName = getRegName(MI->getOperand(0).getReg());
1123     break;
1124 
1125   CASE_UNPCK(UNPCKHPD, r)
1126     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1127     RegForm = true;
1128     LLVM_FALLTHROUGH;
1129 
1130   CASE_UNPCK(UNPCKHPD, m)
1131     DecodeUNPCKHMask(getRegOperandNumElts(MI, 64, 0), 64, ShuffleMask);
1132     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
1133     DestName = getRegName(MI->getOperand(0).getReg());
1134     break;
1135 
1136   CASE_UNPCK(UNPCKHPS, r)
1137     Src2Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1138     RegForm = true;
1139     LLVM_FALLTHROUGH;
1140 
1141   CASE_UNPCK(UNPCKHPS, m)
1142     DecodeUNPCKHMask(getRegOperandNumElts(MI, 32, 0), 32, ShuffleMask);
1143     Src1Name = getRegName(MI->getOperand(NumOperands-(RegForm?2:6)).getReg());
1144     DestName = getRegName(MI->getOperand(0).getReg());
1145     break;
1146 
1147   CASE_VPERMILPI(PERMILPS, r)
1148     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
1149     LLVM_FALLTHROUGH;
1150 
1151   CASE_VPERMILPI(PERMILPS, m)
1152     if (MI->getOperand(NumOperands - 1).isImm())
1153       DecodePSHUFMask(getRegOperandNumElts(MI, 32, 0), 32,
1154                       MI->getOperand(NumOperands - 1).getImm(),
1155                       ShuffleMask);
1156     DestName = getRegName(MI->getOperand(0).getReg());
1157     break;
1158 
1159   CASE_VPERMILPI(PERMILPD, r)
1160     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
1161     LLVM_FALLTHROUGH;
1162 
1163   CASE_VPERMILPI(PERMILPD, m)
1164     if (MI->getOperand(NumOperands - 1).isImm())
1165       DecodePSHUFMask(getRegOperandNumElts(MI, 64, 0), 64,
1166                       MI->getOperand(NumOperands - 1).getImm(),
1167                       ShuffleMask);
1168     DestName = getRegName(MI->getOperand(0).getReg());
1169     break;
1170 
1171   case X86::VPERM2F128rr:
1172   case X86::VPERM2I128rr:
1173     Src2Name = getRegName(MI->getOperand(2).getReg());
1174     LLVM_FALLTHROUGH;
1175 
1176   case X86::VPERM2F128rm:
1177   case X86::VPERM2I128rm:
1178     // For instruction comments purpose, assume the 256-bit vector is v4i64.
1179     if (MI->getOperand(NumOperands - 1).isImm())
1180       DecodeVPERM2X128Mask(4, MI->getOperand(NumOperands - 1).getImm(),
1181                            ShuffleMask);
1182     Src1Name = getRegName(MI->getOperand(1).getReg());
1183     DestName = getRegName(MI->getOperand(0).getReg());
1184     break;
1185 
1186   CASE_VPERM(PERMPD, r)
1187     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
1188     LLVM_FALLTHROUGH;
1189 
1190   CASE_VPERM(PERMPD, m)
1191     if (MI->getOperand(NumOperands - 1).isImm())
1192       DecodeVPERMMask(getRegOperandNumElts(MI, 64, 0),
1193                       MI->getOperand(NumOperands - 1).getImm(),
1194                       ShuffleMask);
1195     DestName = getRegName(MI->getOperand(0).getReg());
1196     break;
1197 
1198   CASE_VPERM(PERMQ, r)
1199     Src1Name = getRegName(MI->getOperand(NumOperands - 2).getReg());
1200     LLVM_FALLTHROUGH;
1201 
1202   CASE_VPERM(PERMQ, m)
1203     if (MI->getOperand(NumOperands - 1).isImm())
1204       DecodeVPERMMask(getRegOperandNumElts(MI, 64, 0),
1205                       MI->getOperand(NumOperands - 1).getImm(),
1206                       ShuffleMask);
1207     DestName = getRegName(MI->getOperand(0).getReg());
1208     break;
1209 
1210   case X86::MOVSDrr:
1211   case X86::VMOVSDrr:
1212   case X86::VMOVSDZrr:
1213     Src2Name = getRegName(MI->getOperand(2).getReg());
1214     Src1Name = getRegName(MI->getOperand(1).getReg());
1215     LLVM_FALLTHROUGH;
1216 
1217   case X86::MOVSDrm_alt:
1218   case X86::MOVSDrm:
1219   case X86::VMOVSDrm_alt:
1220   case X86::VMOVSDrm:
1221   case X86::VMOVSDZrm:
1222   case X86::VMOVSDZrm_alt:
1223     DecodeScalarMoveMask(2, nullptr == Src2Name, ShuffleMask);
1224     DestName = getRegName(MI->getOperand(0).getReg());
1225     break;
1226 
1227   case X86::MOVSSrr:
1228   case X86::VMOVSSrr:
1229   case X86::VMOVSSZrr:
1230     Src2Name = getRegName(MI->getOperand(2).getReg());
1231     Src1Name = getRegName(MI->getOperand(1).getReg());
1232     LLVM_FALLTHROUGH;
1233 
1234   case X86::MOVSSrm:
1235   case X86::MOVSSrm_alt:
1236   case X86::VMOVSSrm:
1237   case X86::VMOVSSrm_alt:
1238   case X86::VMOVSSZrm:
1239   case X86::VMOVSSZrm_alt:
1240     DecodeScalarMoveMask(4, nullptr == Src2Name, ShuffleMask);
1241     DestName = getRegName(MI->getOperand(0).getReg());
1242     break;
1243 
1244   case X86::MOVPQI2QIrr:
1245   case X86::MOVZPQILo2PQIrr:
1246   case X86::VMOVPQI2QIrr:
1247   case X86::VMOVPQI2QIZrr:
1248   case X86::VMOVZPQILo2PQIrr:
1249   case X86::VMOVZPQILo2PQIZrr:
1250     Src1Name = getRegName(MI->getOperand(1).getReg());
1251     LLVM_FALLTHROUGH;
1252 
1253   case X86::MOVQI2PQIrm:
1254   case X86::VMOVQI2PQIrm:
1255   case X86::VMOVQI2PQIZrm:
1256     DecodeZeroMoveLowMask(2, ShuffleMask);
1257     DestName = getRegName(MI->getOperand(0).getReg());
1258     break;
1259 
1260   case X86::MOVDI2PDIrm:
1261   case X86::VMOVDI2PDIrm:
1262   case X86::VMOVDI2PDIZrm:
1263     DecodeZeroMoveLowMask(4, ShuffleMask);
1264     DestName = getRegName(MI->getOperand(0).getReg());
1265     break;
1266 
1267   case X86::EXTRQI:
1268     if (MI->getOperand(2).isImm() &&
1269         MI->getOperand(3).isImm())
1270       DecodeEXTRQIMask(16, 8, MI->getOperand(2).getImm(),
1271                        MI->getOperand(3).getImm(), ShuffleMask);
1272 
1273     DestName = getRegName(MI->getOperand(0).getReg());
1274     Src1Name = getRegName(MI->getOperand(1).getReg());
1275     break;
1276 
1277   case X86::INSERTQI:
1278     if (MI->getOperand(3).isImm() &&
1279         MI->getOperand(4).isImm())
1280       DecodeINSERTQIMask(16, 8, MI->getOperand(3).getImm(),
1281                          MI->getOperand(4).getImm(), ShuffleMask);
1282 
1283     DestName = getRegName(MI->getOperand(0).getReg());
1284     Src1Name = getRegName(MI->getOperand(1).getReg());
1285     Src2Name = getRegName(MI->getOperand(2).getReg());
1286     break;
1287 
1288   case X86::VBROADCASTF128:
1289   case X86::VBROADCASTI128:
1290   CASE_AVX512_INS_COMMON(BROADCASTF64X2, Z128, rm)
1291   CASE_AVX512_INS_COMMON(BROADCASTI64X2, Z128, rm)
1292     DecodeSubVectorBroadcast(4, 2, ShuffleMask);
1293     DestName = getRegName(MI->getOperand(0).getReg());
1294     break;
1295   CASE_AVX512_INS_COMMON(BROADCASTF64X2, , rm)
1296   CASE_AVX512_INS_COMMON(BROADCASTI64X2, , rm)
1297     DecodeSubVectorBroadcast(8, 2, ShuffleMask);
1298     DestName = getRegName(MI->getOperand(0).getReg());
1299     break;
1300   CASE_AVX512_INS_COMMON(BROADCASTF64X4, , rm)
1301   CASE_AVX512_INS_COMMON(BROADCASTI64X4, , rm)
1302     DecodeSubVectorBroadcast(8, 4, ShuffleMask);
1303     DestName = getRegName(MI->getOperand(0).getReg());
1304     break;
1305   CASE_AVX512_INS_COMMON(BROADCASTF32X4, Z256, rm)
1306   CASE_AVX512_INS_COMMON(BROADCASTI32X4, Z256, rm)
1307     DecodeSubVectorBroadcast(8, 4, ShuffleMask);
1308     DestName = getRegName(MI->getOperand(0).getReg());
1309     break;
1310   CASE_AVX512_INS_COMMON(BROADCASTF32X4, , rm)
1311   CASE_AVX512_INS_COMMON(BROADCASTI32X4, , rm)
1312     DecodeSubVectorBroadcast(16, 4, ShuffleMask);
1313     DestName = getRegName(MI->getOperand(0).getReg());
1314     break;
1315   CASE_AVX512_INS_COMMON(BROADCASTF32X8, , rm)
1316   CASE_AVX512_INS_COMMON(BROADCASTI32X8, , rm)
1317     DecodeSubVectorBroadcast(16, 8, ShuffleMask);
1318     DestName = getRegName(MI->getOperand(0).getReg());
1319     break;
1320   CASE_AVX512_INS_COMMON(BROADCASTI32X2, Z128, rr)
1321     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1322     LLVM_FALLTHROUGH;
1323   CASE_AVX512_INS_COMMON(BROADCASTI32X2, Z128, rm)
1324     DecodeSubVectorBroadcast(4, 2, ShuffleMask);
1325     DestName = getRegName(MI->getOperand(0).getReg());
1326     break;
1327   CASE_AVX512_INS_COMMON(BROADCASTF32X2, Z256, rr)
1328   CASE_AVX512_INS_COMMON(BROADCASTI32X2, Z256, rr)
1329     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1330     LLVM_FALLTHROUGH;
1331   CASE_AVX512_INS_COMMON(BROADCASTF32X2, Z256, rm)
1332   CASE_AVX512_INS_COMMON(BROADCASTI32X2, Z256, rm)
1333     DecodeSubVectorBroadcast(8, 2, ShuffleMask);
1334     DestName = getRegName(MI->getOperand(0).getReg());
1335     break;
1336   CASE_AVX512_INS_COMMON(BROADCASTF32X2, Z, rr)
1337   CASE_AVX512_INS_COMMON(BROADCASTI32X2, Z, rr)
1338     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1339     LLVM_FALLTHROUGH;
1340   CASE_AVX512_INS_COMMON(BROADCASTF32X2, Z, rm)
1341   CASE_AVX512_INS_COMMON(BROADCASTI32X2, Z, rm)
1342     DecodeSubVectorBroadcast(16, 2, ShuffleMask);
1343     DestName = getRegName(MI->getOperand(0).getReg());
1344     break;
1345 
1346   CASE_PMOVZX(PMOVZXBW, r)
1347     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1348     LLVM_FALLTHROUGH;
1349   CASE_PMOVZX(PMOVZXBW, m)
1350     DecodeZeroExtendMask(8, 16, getRegOperandNumElts(MI, 16, 0), false,
1351                          ShuffleMask);
1352     DestName = getRegName(MI->getOperand(0).getReg());
1353     break;
1354 
1355   CASE_PMOVZX(PMOVZXBD, r)
1356     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1357     LLVM_FALLTHROUGH;
1358   CASE_PMOVZX(PMOVZXBD, m)
1359     DecodeZeroExtendMask(8, 32, getRegOperandNumElts(MI, 32, 0), false,
1360                          ShuffleMask);
1361     DestName = getRegName(MI->getOperand(0).getReg());
1362     break;
1363 
1364   CASE_PMOVZX(PMOVZXBQ, r)
1365     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1366     LLVM_FALLTHROUGH;
1367   CASE_PMOVZX(PMOVZXBQ, m)
1368     DecodeZeroExtendMask(8, 64, getRegOperandNumElts(MI, 64, 0), false,
1369                          ShuffleMask);
1370     DestName = getRegName(MI->getOperand(0).getReg());
1371     break;
1372 
1373   CASE_PMOVZX(PMOVZXWD, r)
1374     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1375     LLVM_FALLTHROUGH;
1376   CASE_PMOVZX(PMOVZXWD, m)
1377     DecodeZeroExtendMask(16, 32, getRegOperandNumElts(MI, 32, 0), false,
1378                          ShuffleMask);
1379     DestName = getRegName(MI->getOperand(0).getReg());
1380     break;
1381 
1382   CASE_PMOVZX(PMOVZXWQ, r)
1383     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1384     LLVM_FALLTHROUGH;
1385   CASE_PMOVZX(PMOVZXWQ, m)
1386     DecodeZeroExtendMask(16, 64, getRegOperandNumElts(MI, 64, 0), false,
1387                          ShuffleMask);
1388     DestName = getRegName(MI->getOperand(0).getReg());
1389     break;
1390 
1391   CASE_PMOVZX(PMOVZXDQ, r)
1392     Src1Name = getRegName(MI->getOperand(NumOperands - 1).getReg());
1393     LLVM_FALLTHROUGH;
1394   CASE_PMOVZX(PMOVZXDQ, m)
1395     DecodeZeroExtendMask(32, 64, getRegOperandNumElts(MI, 64, 0), false,
1396                          ShuffleMask);
1397     DestName = getRegName(MI->getOperand(0).getReg());
1398     break;
1399   }
1400 
1401   // The only comments we decode are shuffles, so give up if we were unable to
1402   // decode a shuffle mask.
1403   if (ShuffleMask.empty())
1404     return false;
1405 
1406   if (!DestName) DestName = Src1Name;
1407   if (DestName) {
1408     OS << DestName;
1409     printMasking(OS, MI, MCII);
1410   } else
1411     OS << "mem";
1412 
1413   OS << " = ";
1414 
1415   // If the two sources are the same, canonicalize the input elements to be
1416   // from the first src so that we get larger element spans.
1417   if (Src1Name == Src2Name) {
1418     for (unsigned i = 0, e = ShuffleMask.size(); i != e; ++i) {
1419       if ((int)ShuffleMask[i] >= 0 && // Not sentinel.
1420           ShuffleMask[i] >= (int)e)   // From second mask.
1421         ShuffleMask[i] -= e;
1422     }
1423   }
1424 
1425   // The shuffle mask specifies which elements of the src1/src2 fill in the
1426   // destination, with a few sentinel values.  Loop through and print them
1427   // out.
1428   for (unsigned i = 0, e = ShuffleMask.size(); i != e; ++i) {
1429     if (i != 0)
1430       OS << ',';
1431     if (ShuffleMask[i] == SM_SentinelZero) {
1432       OS << "zero";
1433       continue;
1434     }
1435 
1436     // Otherwise, it must come from src1 or src2.  Print the span of elements
1437     // that comes from this src.
1438     bool isSrc1 = ShuffleMask[i] < (int)ShuffleMask.size();
1439     const char *SrcName = isSrc1 ? Src1Name : Src2Name;
1440     OS << (SrcName ? SrcName : "mem") << '[';
1441     bool IsFirst = true;
1442     while (i != e && (int)ShuffleMask[i] != SM_SentinelZero &&
1443            (ShuffleMask[i] < (int)ShuffleMask.size()) == isSrc1) {
1444       if (!IsFirst)
1445         OS << ',';
1446       else
1447         IsFirst = false;
1448       if (ShuffleMask[i] == SM_SentinelUndef)
1449         OS << "u";
1450       else
1451         OS << ShuffleMask[i] % ShuffleMask.size();
1452       ++i;
1453     }
1454     OS << ']';
1455     --i; // For loop increments element #.
1456   }
1457   OS << '\n';
1458 
1459   // We successfully added a comment to this instruction.
1460   return true;
1461 }
1462