1 //===- CombinerHelperArtifacts.cpp-----------------------------------------===//
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 file implements CombinerHelper for legalization artifacts.
10 //
11 //===----------------------------------------------------------------------===//
12 //
13 // G_MERGE_VALUES
14 //
15 //===----------------------------------------------------------------------===//
16 #include "llvm/CodeGen/GlobalISel/CombinerHelper.h"
17 #include "llvm/CodeGen/GlobalISel/LegalizerHelper.h"
18 #include "llvm/CodeGen/GlobalISel/LegalizerInfo.h"
19 #include "llvm/CodeGen/GlobalISel/MachineIRBuilder.h"
20 #include "llvm/CodeGen/GlobalISel/Utils.h"
21 #include "llvm/CodeGen/MachineOperand.h"
22 #include "llvm/CodeGen/MachineRegisterInfo.h"
23 #include "llvm/CodeGen/TargetOpcodes.h"
24 #include "llvm/Support/Casting.h"
25
26 #define DEBUG_TYPE "gi-combiner"
27
28 using namespace llvm;
29
matchMergeXAndUndef(const MachineInstr & MI,BuildFnTy & MatchInfo) const30 bool CombinerHelper::matchMergeXAndUndef(const MachineInstr &MI,
31 BuildFnTy &MatchInfo) const {
32 const GMerge *Merge = cast<GMerge>(&MI);
33
34 Register Dst = Merge->getReg(0);
35 LLT DstTy = MRI.getType(Dst);
36 LLT SrcTy = MRI.getType(Merge->getSourceReg(0));
37
38 // Otherwise, we would miscompile.
39 assert(Merge->getNumSources() == 2 && "Unexpected number of operands");
40
41 //
42 // %bits_8_15:_(s8) = G_IMPLICIT_DEF
43 // %0:_(s16) = G_MERGE_VALUES %bits_0_7:(s8), %bits_8_15:(s8)
44 //
45 // ->
46 //
47 // %0:_(s16) = G_ANYEXT %bits_0_7:(s8)
48 //
49
50 if (!isLegalOrBeforeLegalizer({TargetOpcode::G_ANYEXT, {DstTy, SrcTy}}))
51 return false;
52
53 MatchInfo = [=](MachineIRBuilder &B) {
54 B.buildAnyExt(Dst, Merge->getSourceReg(0));
55 };
56 return true;
57 }
58
matchMergeXAndZero(const MachineInstr & MI,BuildFnTy & MatchInfo) const59 bool CombinerHelper::matchMergeXAndZero(const MachineInstr &MI,
60 BuildFnTy &MatchInfo) const {
61 const GMerge *Merge = cast<GMerge>(&MI);
62
63 Register Dst = Merge->getReg(0);
64 LLT DstTy = MRI.getType(Dst);
65 LLT SrcTy = MRI.getType(Merge->getSourceReg(0));
66
67 // No multi-use check. It is a constant.
68
69 //
70 // %bits_8_15:_(s8) = G_CONSTANT i8 0
71 // %0:_(s16) = G_MERGE_VALUES %bits_0_7:(s8), %bits_8_15:(s8)
72 //
73 // ->
74 //
75 // %0:_(s16) = G_ZEXT %bits_0_7:(s8)
76 //
77
78 if (!isLegalOrBeforeLegalizer({TargetOpcode::G_ZEXT, {DstTy, SrcTy}}))
79 return false;
80
81 MatchInfo = [=](MachineIRBuilder &B) {
82 B.buildZExt(Dst, Merge->getSourceReg(0));
83 };
84 return true;
85 }
86