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[GlobalISel] Add Knownbits for G_LOAD/ZEXTLOAD/SEXTLOAD with range metadata #86431

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Merged
merged 1 commit into from
Mar 26, 2024
Merged

[GlobalISel] Add Knownbits for G_LOAD/ZEXTLOAD/SEXTLOAD with range metadata #86431

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19 changes: 12 additions & 7 deletions llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -405,18 +405,23 @@ void GISelKnownBits::computeKnownBitsImpl(Register R, KnownBits &Known,
}
case TargetOpcode::G_LOAD: {
const MachineMemOperand *MMO = *MI.memoperands_begin();
if (const MDNode *Ranges = MMO->getRanges()) {
computeKnownBitsFromRangeMetadata(*Ranges, Known);
}

KnownBits KnownRange(MMO->getMemoryType().getScalarSizeInBits());
if (const MDNode *Ranges = MMO->getRanges())
computeKnownBitsFromRangeMetadata(*Ranges, KnownRange);
Known = KnownRange.anyext(Known.getBitWidth());
break;
}
case TargetOpcode::G_SEXTLOAD:
case TargetOpcode::G_ZEXTLOAD: {
if (DstTy.isVector())
break;
// Everything above the retrieved bits is zero
Known.Zero.setBitsFrom(
(*MI.memoperands_begin())->getSizeInBits().getValue());
const MachineMemOperand *MMO = *MI.memoperands_begin();
KnownBits KnownRange(MMO->getMemoryType().getScalarSizeInBits());
if (const MDNode *Ranges = MMO->getRanges())
computeKnownBitsFromRangeMetadata(*Ranges, KnownRange);
Known = Opcode == TargetOpcode::G_SEXTLOAD
? KnownRange.sext(Known.getBitWidth())
: KnownRange.zext(Known.getBitWidth());
break;
}
case TargetOpcode::G_ASHR: {
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94 changes: 80 additions & 14 deletions llvm/unittests/CodeGen/GlobalISel/KnownBitsTest.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1100,6 +1100,25 @@ TEST_F(AMDGPUGISelMITest, TestIsKnownToBeAPowerOfTwo) {
EXPECT_TRUE(isKnownToBeAPowerOfTwo(CopyOrPow2, *MRI, &KB));
}

static void AddRangeMetadata(LLVMContext &Context, MachineInstr *Load) {
IntegerType *Int8Ty = Type::getInt8Ty(Context);

// Value must be in [0, 2)
Metadata *LowAndHigh[] = {
ConstantAsMetadata::get(ConstantInt::get(Int8Ty, 0)),
ConstantAsMetadata::get(ConstantInt::get(Int8Ty, 2))};
auto NewMDNode = MDNode::get(Context, LowAndHigh);
const MachineMemOperand *OldMMO = *Load->memoperands_begin();
MachineMemOperand *NewMMO =
Load->getParent()->getParent()->getMachineMemOperand(
OldMMO->getPointerInfo(), OldMMO->getFlags(), OldMMO->getMemoryType(),
OldMMO->getAlign(), OldMMO->getAAInfo(), NewMDNode);
MachineIRBuilder MIB(*Load);
MIB.buildLoadInstr(Load->getOpcode(), Load->getOperand(0),
Load->getOperand(1), *NewMMO);
Load->eraseFromParent();
}

TEST_F(AArch64GISelMITest, TestMetadata) {
StringRef MIRString = " %imp:_(p0) = G_IMPLICIT_DEF\n"
" %load:_(s8) = G_LOAD %imp(p0) :: (load (s8))\n"
Expand All @@ -1120,20 +1139,7 @@ TEST_F(AArch64GISelMITest, TestMetadata) {
MachineInstr *And = MRI->getVRegDef(SrcReg);
MachineInstr *Ext = MRI->getVRegDef(And->getOperand(1).getReg());
MachineInstr *Load = MRI->getVRegDef(Ext->getOperand(1).getReg());
IntegerType *Int8Ty = Type::getInt8Ty(Context);

// Value must be in [0, 2)
Metadata *LowAndHigh[] = {
ConstantAsMetadata::get(ConstantInt::get(Int8Ty, 0)),
ConstantAsMetadata::get(ConstantInt::get(Int8Ty, 2))};
auto NewMDNode = MDNode::get(Context, LowAndHigh);
const MachineMemOperand *OldMMO = *Load->memoperands_begin();
MachineMemOperand NewMMO(OldMMO->getPointerInfo(), OldMMO->getFlags(),
OldMMO->getSizeInBits(), OldMMO->getAlign(),
OldMMO->getAAInfo(), NewMDNode);
MachineIRBuilder MIB(*Load);
MIB.buildLoad(Load->getOperand(0), Load->getOperand(1), NewMMO);
Load->eraseFromParent();
AddRangeMetadata(Context, Load);

GISelKnownBits Info(*MF);
KnownBits Res = Info.getKnownBits(And->getOperand(1).getReg());
Expand All @@ -1148,6 +1154,66 @@ TEST_F(AArch64GISelMITest, TestMetadata) {
EXPECT_EQ(Mask.getZExtValue(), Res.Zero.getZExtValue());
}

TEST_F(AArch64GISelMITest, TestMetadataExt) {
StringRef MIRString = " %imp:_(p0) = G_IMPLICIT_DEF\n"
" %load:_(s32) = G_LOAD %imp(p0) :: (load (s8))\n"
" %copy:_(s32) = COPY %load(s32)\n";
setUp(MIRString);
if (!TM)
GTEST_SKIP();

Register CopyReg = Copies[Copies.size() - 1];
MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
Register SrcReg = FinalCopy->getOperand(1).getReg();
MachineInstr *Load = MRI->getVRegDef(SrcReg);
AddRangeMetadata(Context, Load);

GISelKnownBits Info(*MF);
KnownBits Res = Info.getKnownBits(SrcReg);
EXPECT_TRUE(Res.One.isZero());
EXPECT_EQ(Res.Zero.getZExtValue(), 0xfeu);
}

TEST_F(AArch64GISelMITest, TestMetadataZExt) {
StringRef MIRString = " %imp:_(p0) = G_IMPLICIT_DEF\n"
" %load:_(s32) = G_ZEXTLOAD %imp(p0) :: (load (s8))\n"
" %copy:_(s32) = COPY %load(s32)\n";
setUp(MIRString);
if (!TM)
GTEST_SKIP();

Register CopyReg = Copies[Copies.size() - 1];
MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
Register SrcReg = FinalCopy->getOperand(1).getReg();
MachineInstr *Load = MRI->getVRegDef(SrcReg);
AddRangeMetadata(Context, Load);

GISelKnownBits Info(*MF);
KnownBits Res = Info.getKnownBits(SrcReg);
EXPECT_TRUE(Res.One.isZero());
EXPECT_EQ(Res.Zero.getZExtValue(), 0xfffffffe);
}

TEST_F(AArch64GISelMITest, TestMetadataSExt) {
StringRef MIRString = " %imp:_(p0) = G_IMPLICIT_DEF\n"
" %load:_(s32) = G_SEXTLOAD %imp(p0) :: (load (s8))\n"
" %copy:_(s32) = COPY %load(s32)\n";
setUp(MIRString);
if (!TM)
GTEST_SKIP();

Register CopyReg = Copies[Copies.size() - 1];
MachineInstr *FinalCopy = MRI->getVRegDef(CopyReg);
Register SrcReg = FinalCopy->getOperand(1).getReg();
MachineInstr *Load = MRI->getVRegDef(SrcReg);
AddRangeMetadata(Context, Load);

GISelKnownBits Info(*MF);
KnownBits Res = Info.getKnownBits(SrcReg);
EXPECT_TRUE(Res.One.isZero());
EXPECT_EQ(Res.Zero.getZExtValue(), 0xfffffffe);
}

TEST_F(AArch64GISelMITest, TestKnownBitsExt) {
StringRef MIRString = " %c1:_(s16) = G_CONSTANT i16 1\n"
" %x:_(s16) = G_IMPLICIT_DEF\n"
Expand Down
2 changes: 1 addition & 1 deletion llvm/unittests/CodeGen/GlobalISel/KnownBitsVectorTest.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1008,7 +1008,7 @@ TEST_F(AArch64GISelMITest, TestVectorMetadata) {
auto *NewMDNode = MDNode::get(Context, LowAndHigh);
const MachineMemOperand *OldMMO = *Load->memoperands_begin();
MachineMemOperand NewMMO(OldMMO->getPointerInfo(), OldMMO->getFlags(),
OldMMO->getSizeInBits(), OldMMO->getAlign(),
OldMMO->getMemoryType(), OldMMO->getAlign(),
OldMMO->getAAInfo(), NewMDNode);
MachineIRBuilder MIB(*Load);
MIB.buildLoad(Load->getOperand(0), Load->getOperand(1), NewMMO);
Expand Down