xref: /freebsd/contrib/llvm-project/llvm/lib/Target/ARM/ARMLegalizerInfo.cpp (revision 0fca6ea1d4eea4c934cfff25ac9ee8ad6fe95583)
1 //===- ARMLegalizerInfo.cpp --------------------------------------*- C++ -*-==//
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 /// \file
9 /// This file implements the targeting of the Machinelegalizer class for ARM.
10 /// \todo This should be generated by TableGen.
11 //===----------------------------------------------------------------------===//
12 
13 #include "ARMLegalizerInfo.h"
14 #include "ARMCallLowering.h"
15 #include "ARMSubtarget.h"
16 #include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
17 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
18 #include "llvm/CodeGen/LowLevelTypeUtils.h"
19 #include "llvm/CodeGen/MachineRegisterInfo.h"
20 #include "llvm/CodeGen/TargetOpcodes.h"
21 #include "llvm/CodeGen/ValueTypes.h"
22 #include "llvm/IR/DerivedTypes.h"
23 #include "llvm/IR/Type.h"
24 
25 using namespace llvm;
26 using namespace LegalizeActions;
27 
AEABI(const ARMSubtarget & ST)28 static bool AEABI(const ARMSubtarget &ST) {
29   return ST.isTargetAEABI() || ST.isTargetGNUAEABI() || ST.isTargetMuslAEABI();
30 }
31 
ARMLegalizerInfo(const ARMSubtarget & ST)32 ARMLegalizerInfo::ARMLegalizerInfo(const ARMSubtarget &ST) {
33   using namespace TargetOpcode;
34 
35   const LLT p0 = LLT::pointer(0, 32);
36 
37   const LLT s1 = LLT::scalar(1);
38   const LLT s8 = LLT::scalar(8);
39   const LLT s16 = LLT::scalar(16);
40   const LLT s32 = LLT::scalar(32);
41   const LLT s64 = LLT::scalar(64);
42 
43   auto &LegacyInfo = getLegacyLegalizerInfo();
44   if (ST.isThumb1Only()) {
45     // Thumb1 is not supported yet.
46     LegacyInfo.computeTables();
47     verify(*ST.getInstrInfo());
48     return;
49   }
50 
51   getActionDefinitionsBuilder({G_SEXT, G_ZEXT, G_ANYEXT})
52       .legalForCartesianProduct({s8, s16, s32}, {s1, s8, s16});
53 
54   getActionDefinitionsBuilder(G_SEXT_INREG).lower();
55 
56   getActionDefinitionsBuilder({G_MUL, G_AND, G_OR, G_XOR})
57       .legalFor({s32})
58       .clampScalar(0, s32, s32);
59 
60   if (ST.hasNEON())
61     getActionDefinitionsBuilder({G_ADD, G_SUB})
62         .legalFor({s32, s64})
63         .minScalar(0, s32);
64   else
65     getActionDefinitionsBuilder({G_ADD, G_SUB})
66         .legalFor({s32})
67         .minScalar(0, s32);
68 
69   getActionDefinitionsBuilder({G_ASHR, G_LSHR, G_SHL})
70     .legalFor({{s32, s32}})
71     .minScalar(0, s32)
72     .clampScalar(1, s32, s32);
73 
74   bool HasHWDivide = (!ST.isThumb() && ST.hasDivideInARMMode()) ||
75                      (ST.isThumb() && ST.hasDivideInThumbMode());
76   if (HasHWDivide)
77     getActionDefinitionsBuilder({G_SDIV, G_UDIV})
78         .legalFor({s32})
79         .clampScalar(0, s32, s32);
80   else
81     getActionDefinitionsBuilder({G_SDIV, G_UDIV})
82         .libcallFor({s32})
83         .clampScalar(0, s32, s32);
84 
85   auto &REMBuilder =
86       getActionDefinitionsBuilder({G_SREM, G_UREM}).minScalar(0, s32);
87   if (HasHWDivide)
88     REMBuilder.lowerFor({s32});
89   else if (AEABI(ST))
90     REMBuilder.customFor({s32});
91   else
92     REMBuilder.libcallFor({s32});
93 
94   getActionDefinitionsBuilder(G_INTTOPTR)
95       .legalFor({{p0, s32}})
96       .minScalar(1, s32);
97   getActionDefinitionsBuilder(G_PTRTOINT)
98       .legalFor({{s32, p0}})
99       .minScalar(0, s32);
100 
101   getActionDefinitionsBuilder(G_CONSTANT)
102       .legalFor({s32, p0})
103       .clampScalar(0, s32, s32);
104 
105   getActionDefinitionsBuilder(G_ICMP)
106       .legalForCartesianProduct({s1}, {s32, p0})
107       .minScalar(1, s32);
108 
109   getActionDefinitionsBuilder(G_SELECT)
110       .legalForCartesianProduct({s32, p0}, {s1})
111       .minScalar(0, s32);
112 
113   // We're keeping these builders around because we'll want to add support for
114   // floating point to them.
115   auto &LoadStoreBuilder = getActionDefinitionsBuilder({G_LOAD, G_STORE})
116                                .legalForTypesWithMemDesc({{s8, p0, s8, 8},
117                                                           {s16, p0, s16, 8},
118                                                           {s32, p0, s32, 8},
119                                                           {p0, p0, p0, 8}})
120                                .unsupportedIfMemSizeNotPow2();
121 
122   getActionDefinitionsBuilder(G_FRAME_INDEX).legalFor({p0});
123   getActionDefinitionsBuilder(G_GLOBAL_VALUE).legalFor({p0});
124 
125   auto &PhiBuilder =
126       getActionDefinitionsBuilder(G_PHI)
127           .legalFor({s32, p0})
128           .minScalar(0, s32);
129 
130   getActionDefinitionsBuilder(G_PTR_ADD)
131       .legalFor({{p0, s32}})
132       .minScalar(1, s32);
133 
134   getActionDefinitionsBuilder(G_BRCOND).legalFor({s1});
135 
136   if (!ST.useSoftFloat() && ST.hasVFP2Base()) {
137     getActionDefinitionsBuilder(
138         {G_FADD, G_FSUB, G_FMUL, G_FDIV, G_FCONSTANT, G_FNEG})
139         .legalFor({s32, s64});
140 
141     LoadStoreBuilder
142         .legalForTypesWithMemDesc({{s64, p0, s64, 32}})
143         .maxScalar(0, s32);
144     PhiBuilder.legalFor({s64});
145 
146     getActionDefinitionsBuilder(G_FCMP).legalForCartesianProduct({s1},
147                                                                  {s32, s64});
148 
149     getActionDefinitionsBuilder(G_MERGE_VALUES).legalFor({{s64, s32}});
150     getActionDefinitionsBuilder(G_UNMERGE_VALUES).legalFor({{s32, s64}});
151 
152     getActionDefinitionsBuilder(G_FPEXT).legalFor({{s64, s32}});
153     getActionDefinitionsBuilder(G_FPTRUNC).legalFor({{s32, s64}});
154 
155     getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
156         .legalForCartesianProduct({s32}, {s32, s64});
157     getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
158         .legalForCartesianProduct({s32, s64}, {s32});
159 
160     getActionDefinitionsBuilder({G_GET_FPENV, G_SET_FPENV, G_GET_FPMODE})
161         .legalFor({s32});
162     getActionDefinitionsBuilder(G_RESET_FPENV).alwaysLegal();
163     getActionDefinitionsBuilder(G_SET_FPMODE).customFor({s32});
164   } else {
165     getActionDefinitionsBuilder({G_FADD, G_FSUB, G_FMUL, G_FDIV})
166         .libcallFor({s32, s64});
167 
168     LoadStoreBuilder.maxScalar(0, s32);
169 
170     getActionDefinitionsBuilder(G_FNEG).lowerFor({s32, s64});
171 
172     getActionDefinitionsBuilder(G_FCONSTANT).customFor({s32, s64});
173 
174     getActionDefinitionsBuilder(G_FCMP).customForCartesianProduct({s1},
175                                                                   {s32, s64});
176 
177     if (AEABI(ST))
178       setFCmpLibcallsAEABI();
179     else
180       setFCmpLibcallsGNU();
181 
182     getActionDefinitionsBuilder(G_FPEXT).libcallFor({{s64, s32}});
183     getActionDefinitionsBuilder(G_FPTRUNC).libcallFor({{s32, s64}});
184 
185     getActionDefinitionsBuilder({G_FPTOSI, G_FPTOUI})
186         .libcallForCartesianProduct({s32}, {s32, s64});
187     getActionDefinitionsBuilder({G_SITOFP, G_UITOFP})
188         .libcallForCartesianProduct({s32, s64}, {s32});
189 
190     getActionDefinitionsBuilder({G_GET_FPENV, G_SET_FPENV, G_RESET_FPENV})
191         .libcall();
192     getActionDefinitionsBuilder({G_GET_FPMODE, G_SET_FPMODE, G_RESET_FPMODE})
193         .libcall();
194   }
195 
196   // Just expand whatever loads and stores are left.
197   LoadStoreBuilder.lower();
198 
199   if (!ST.useSoftFloat() && ST.hasVFP4Base())
200     getActionDefinitionsBuilder(G_FMA).legalFor({s32, s64});
201   else
202     getActionDefinitionsBuilder(G_FMA).libcallFor({s32, s64});
203 
204   getActionDefinitionsBuilder({G_FREM, G_FPOW}).libcallFor({s32, s64});
205 
206   if (ST.hasV5TOps()) {
207     getActionDefinitionsBuilder(G_CTLZ)
208         .legalFor({s32, s32})
209         .clampScalar(1, s32, s32)
210         .clampScalar(0, s32, s32);
211     getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
212         .lowerFor({s32, s32})
213         .clampScalar(1, s32, s32)
214         .clampScalar(0, s32, s32);
215   } else {
216     getActionDefinitionsBuilder(G_CTLZ_ZERO_UNDEF)
217         .libcallFor({s32, s32})
218         .clampScalar(1, s32, s32)
219         .clampScalar(0, s32, s32);
220     getActionDefinitionsBuilder(G_CTLZ)
221         .lowerFor({s32, s32})
222         .clampScalar(1, s32, s32)
223         .clampScalar(0, s32, s32);
224   }
225 
226   LegacyInfo.computeTables();
227   verify(*ST.getInstrInfo());
228 }
229 
setFCmpLibcallsAEABI()230 void ARMLegalizerInfo::setFCmpLibcallsAEABI() {
231   // FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
232   // default-initialized.
233   FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
234   FCmp32Libcalls[CmpInst::FCMP_OEQ] = {
235       {RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE}};
236   FCmp32Libcalls[CmpInst::FCMP_OGE] = {
237       {RTLIB::OGE_F32, CmpInst::BAD_ICMP_PREDICATE}};
238   FCmp32Libcalls[CmpInst::FCMP_OGT] = {
239       {RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE}};
240   FCmp32Libcalls[CmpInst::FCMP_OLE] = {
241       {RTLIB::OLE_F32, CmpInst::BAD_ICMP_PREDICATE}};
242   FCmp32Libcalls[CmpInst::FCMP_OLT] = {
243       {RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
244   FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::UO_F32, CmpInst::ICMP_EQ}};
245   FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_EQ}};
246   FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_EQ}};
247   FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_EQ}};
248   FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_EQ}};
249   FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_EQ}};
250   FCmp32Libcalls[CmpInst::FCMP_UNO] = {
251       {RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
252   FCmp32Libcalls[CmpInst::FCMP_ONE] = {
253       {RTLIB::OGT_F32, CmpInst::BAD_ICMP_PREDICATE},
254       {RTLIB::OLT_F32, CmpInst::BAD_ICMP_PREDICATE}};
255   FCmp32Libcalls[CmpInst::FCMP_UEQ] = {
256       {RTLIB::OEQ_F32, CmpInst::BAD_ICMP_PREDICATE},
257       {RTLIB::UO_F32, CmpInst::BAD_ICMP_PREDICATE}};
258 
259   FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
260   FCmp64Libcalls[CmpInst::FCMP_OEQ] = {
261       {RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE}};
262   FCmp64Libcalls[CmpInst::FCMP_OGE] = {
263       {RTLIB::OGE_F64, CmpInst::BAD_ICMP_PREDICATE}};
264   FCmp64Libcalls[CmpInst::FCMP_OGT] = {
265       {RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE}};
266   FCmp64Libcalls[CmpInst::FCMP_OLE] = {
267       {RTLIB::OLE_F64, CmpInst::BAD_ICMP_PREDICATE}};
268   FCmp64Libcalls[CmpInst::FCMP_OLT] = {
269       {RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
270   FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::UO_F64, CmpInst::ICMP_EQ}};
271   FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_EQ}};
272   FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_EQ}};
273   FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_EQ}};
274   FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_EQ}};
275   FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_EQ}};
276   FCmp64Libcalls[CmpInst::FCMP_UNO] = {
277       {RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
278   FCmp64Libcalls[CmpInst::FCMP_ONE] = {
279       {RTLIB::OGT_F64, CmpInst::BAD_ICMP_PREDICATE},
280       {RTLIB::OLT_F64, CmpInst::BAD_ICMP_PREDICATE}};
281   FCmp64Libcalls[CmpInst::FCMP_UEQ] = {
282       {RTLIB::OEQ_F64, CmpInst::BAD_ICMP_PREDICATE},
283       {RTLIB::UO_F64, CmpInst::BAD_ICMP_PREDICATE}};
284 }
285 
setFCmpLibcallsGNU()286 void ARMLegalizerInfo::setFCmpLibcallsGNU() {
287   // FCMP_TRUE and FCMP_FALSE don't need libcalls, they should be
288   // default-initialized.
289   FCmp32Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
290   FCmp32Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ}};
291   FCmp32Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F32, CmpInst::ICMP_SGE}};
292   FCmp32Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT}};
293   FCmp32Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F32, CmpInst::ICMP_SLE}};
294   FCmp32Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
295   FCmp32Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::UO_F32, CmpInst::ICMP_EQ}};
296   FCmp32Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F32, CmpInst::ICMP_SGE}};
297   FCmp32Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F32, CmpInst::ICMP_SGT}};
298   FCmp32Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SLE}};
299   FCmp32Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F32, CmpInst::ICMP_SLT}};
300   FCmp32Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F32, CmpInst::ICMP_NE}};
301   FCmp32Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F32, CmpInst::ICMP_NE}};
302   FCmp32Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F32, CmpInst::ICMP_SGT},
303                                        {RTLIB::OLT_F32, CmpInst::ICMP_SLT}};
304   FCmp32Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F32, CmpInst::ICMP_EQ},
305                                        {RTLIB::UO_F32, CmpInst::ICMP_NE}};
306 
307   FCmp64Libcalls.resize(CmpInst::LAST_FCMP_PREDICATE + 1);
308   FCmp64Libcalls[CmpInst::FCMP_OEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ}};
309   FCmp64Libcalls[CmpInst::FCMP_OGE] = {{RTLIB::OGE_F64, CmpInst::ICMP_SGE}};
310   FCmp64Libcalls[CmpInst::FCMP_OGT] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT}};
311   FCmp64Libcalls[CmpInst::FCMP_OLE] = {{RTLIB::OLE_F64, CmpInst::ICMP_SLE}};
312   FCmp64Libcalls[CmpInst::FCMP_OLT] = {{RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
313   FCmp64Libcalls[CmpInst::FCMP_ORD] = {{RTLIB::UO_F64, CmpInst::ICMP_EQ}};
314   FCmp64Libcalls[CmpInst::FCMP_UGE] = {{RTLIB::OLT_F64, CmpInst::ICMP_SGE}};
315   FCmp64Libcalls[CmpInst::FCMP_UGT] = {{RTLIB::OLE_F64, CmpInst::ICMP_SGT}};
316   FCmp64Libcalls[CmpInst::FCMP_ULE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SLE}};
317   FCmp64Libcalls[CmpInst::FCMP_ULT] = {{RTLIB::OGE_F64, CmpInst::ICMP_SLT}};
318   FCmp64Libcalls[CmpInst::FCMP_UNE] = {{RTLIB::UNE_F64, CmpInst::ICMP_NE}};
319   FCmp64Libcalls[CmpInst::FCMP_UNO] = {{RTLIB::UO_F64, CmpInst::ICMP_NE}};
320   FCmp64Libcalls[CmpInst::FCMP_ONE] = {{RTLIB::OGT_F64, CmpInst::ICMP_SGT},
321                                        {RTLIB::OLT_F64, CmpInst::ICMP_SLT}};
322   FCmp64Libcalls[CmpInst::FCMP_UEQ] = {{RTLIB::OEQ_F64, CmpInst::ICMP_EQ},
323                                        {RTLIB::UO_F64, CmpInst::ICMP_NE}};
324 }
325 
326 ARMLegalizerInfo::FCmpLibcallsList
getFCmpLibcalls(CmpInst::Predicate Predicate,unsigned Size) const327 ARMLegalizerInfo::getFCmpLibcalls(CmpInst::Predicate Predicate,
328                                   unsigned Size) const {
329   assert(CmpInst::isFPPredicate(Predicate) && "Unsupported FCmp predicate");
330   if (Size == 32)
331     return FCmp32Libcalls[Predicate];
332   if (Size == 64)
333     return FCmp64Libcalls[Predicate];
334   llvm_unreachable("Unsupported size for FCmp predicate");
335 }
336 
legalizeCustom(LegalizerHelper & Helper,MachineInstr & MI,LostDebugLocObserver & LocObserver) const337 bool ARMLegalizerInfo::legalizeCustom(LegalizerHelper &Helper, MachineInstr &MI,
338                                       LostDebugLocObserver &LocObserver) const {
339   using namespace TargetOpcode;
340 
341   MachineIRBuilder &MIRBuilder = Helper.MIRBuilder;
342   MachineRegisterInfo &MRI = *MIRBuilder.getMRI();
343   LLVMContext &Ctx = MIRBuilder.getMF().getFunction().getContext();
344 
345   switch (MI.getOpcode()) {
346   default:
347     return false;
348   case G_SREM:
349   case G_UREM: {
350     Register OriginalResult = MI.getOperand(0).getReg();
351     auto Size = MRI.getType(OriginalResult).getSizeInBits();
352     if (Size != 32)
353       return false;
354 
355     auto Libcall =
356         MI.getOpcode() == G_SREM ? RTLIB::SDIVREM_I32 : RTLIB::UDIVREM_I32;
357 
358     // Our divmod libcalls return a struct containing the quotient and the
359     // remainder. Create a new, unused register for the quotient and use the
360     // destination of the original instruction for the remainder.
361     Type *ArgTy = Type::getInt32Ty(Ctx);
362     StructType *RetTy = StructType::get(Ctx, {ArgTy, ArgTy}, /* Packed */ true);
363     Register RetRegs[] = {MRI.createGenericVirtualRegister(LLT::scalar(32)),
364                           OriginalResult};
365     auto Status = createLibcall(MIRBuilder, Libcall, {RetRegs, RetTy, 0},
366                                 {{MI.getOperand(1).getReg(), ArgTy, 0},
367                                  {MI.getOperand(2).getReg(), ArgTy, 0}},
368                                 LocObserver, &MI);
369     if (Status != LegalizerHelper::Legalized)
370       return false;
371     break;
372   }
373   case G_FCMP: {
374     assert(MRI.getType(MI.getOperand(2).getReg()) ==
375                MRI.getType(MI.getOperand(3).getReg()) &&
376            "Mismatched operands for G_FCMP");
377     auto OpSize = MRI.getType(MI.getOperand(2).getReg()).getSizeInBits();
378 
379     auto OriginalResult = MI.getOperand(0).getReg();
380     auto Predicate =
381         static_cast<CmpInst::Predicate>(MI.getOperand(1).getPredicate());
382     auto Libcalls = getFCmpLibcalls(Predicate, OpSize);
383 
384     if (Libcalls.empty()) {
385       assert((Predicate == CmpInst::FCMP_TRUE ||
386               Predicate == CmpInst::FCMP_FALSE) &&
387              "Predicate needs libcalls, but none specified");
388       MIRBuilder.buildConstant(OriginalResult,
389                                Predicate == CmpInst::FCMP_TRUE ? 1 : 0);
390       MI.eraseFromParent();
391       return true;
392     }
393 
394     assert((OpSize == 32 || OpSize == 64) && "Unsupported operand size");
395     auto *ArgTy = OpSize == 32 ? Type::getFloatTy(Ctx) : Type::getDoubleTy(Ctx);
396     auto *RetTy = Type::getInt32Ty(Ctx);
397 
398     SmallVector<Register, 2> Results;
399     for (auto Libcall : Libcalls) {
400       auto LibcallResult = MRI.createGenericVirtualRegister(LLT::scalar(32));
401       auto Status = createLibcall(MIRBuilder, Libcall.LibcallID,
402                                   {LibcallResult, RetTy, 0},
403                                   {{MI.getOperand(2).getReg(), ArgTy, 0},
404                                    {MI.getOperand(3).getReg(), ArgTy, 0}},
405                                   LocObserver, &MI);
406 
407       if (Status != LegalizerHelper::Legalized)
408         return false;
409 
410       auto ProcessedResult =
411           Libcalls.size() == 1
412               ? OriginalResult
413               : MRI.createGenericVirtualRegister(MRI.getType(OriginalResult));
414 
415       // We have a result, but we need to transform it into a proper 1-bit 0 or
416       // 1, taking into account the different peculiarities of the values
417       // returned by the comparison functions.
418       CmpInst::Predicate ResultPred = Libcall.Predicate;
419       if (ResultPred == CmpInst::BAD_ICMP_PREDICATE) {
420         // We have a nice 0 or 1, and we just need to truncate it back to 1 bit
421         // to keep the types consistent.
422         MIRBuilder.buildTrunc(ProcessedResult, LibcallResult);
423       } else {
424         // We need to compare against 0.
425         assert(CmpInst::isIntPredicate(ResultPred) && "Unsupported predicate");
426         auto Zero = MIRBuilder.buildConstant(LLT::scalar(32), 0);
427         MIRBuilder.buildICmp(ResultPred, ProcessedResult, LibcallResult, Zero);
428       }
429       Results.push_back(ProcessedResult);
430     }
431 
432     if (Results.size() != 1) {
433       assert(Results.size() == 2 && "Unexpected number of results");
434       MIRBuilder.buildOr(OriginalResult, Results[0], Results[1]);
435     }
436     break;
437   }
438   case G_FCONSTANT: {
439     // Convert to integer constants, while preserving the binary representation.
440     auto AsInteger =
441         MI.getOperand(1).getFPImm()->getValueAPF().bitcastToAPInt();
442     MIRBuilder.buildConstant(MI.getOperand(0),
443                              *ConstantInt::get(Ctx, AsInteger));
444     break;
445   }
446   case G_SET_FPMODE: {
447     // New FPSCR = (FPSCR & FPStatusBits) | (Modes & ~FPStatusBits)
448     LLT FPEnvTy = LLT::scalar(32);
449     auto FPEnv = MRI.createGenericVirtualRegister(FPEnvTy);
450     Register Modes = MI.getOperand(0).getReg();
451     MIRBuilder.buildGetFPEnv(FPEnv);
452     auto StatusBitMask = MIRBuilder.buildConstant(FPEnvTy, ARM::FPStatusBits);
453     auto StatusBits = MIRBuilder.buildAnd(FPEnvTy, FPEnv, StatusBitMask);
454     auto NotStatusBitMask =
455         MIRBuilder.buildConstant(FPEnvTy, ~ARM::FPStatusBits);
456     auto FPModeBits = MIRBuilder.buildAnd(FPEnvTy, Modes, NotStatusBitMask);
457     auto NewFPSCR = MIRBuilder.buildOr(FPEnvTy, StatusBits, FPModeBits);
458     MIRBuilder.buildSetFPEnv(NewFPSCR);
459     break;
460   }
461   }
462 
463   MI.eraseFromParent();
464   return true;
465 }
466