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[LLVM][IR] Teach constant integer binop folds about vector ConstantInts. #115739

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Merged
merged 1 commit into from
Nov 13, 2024
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[LLVM][IR] Teach constant integer binop folds about vector ConstantInts. #115739

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50 changes: 23 additions & 27 deletions llvm/lib/IR/ConstantFold.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -231,26 +231,20 @@ Constant *llvm::ConstantFoldCastInstruction(unsigned opc, Constant *V,
return nullptr;
case Instruction::ZExt:
if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
return ConstantInt::get(V->getContext(),
CI->getValue().zext(BitWidth));
uint32_t BitWidth = DestTy->getScalarSizeInBits();
return ConstantInt::get(DestTy, CI->getValue().zext(BitWidth));
}
return nullptr;
case Instruction::SExt:
if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
uint32_t BitWidth = cast<IntegerType>(DestTy)->getBitWidth();
return ConstantInt::get(V->getContext(),
CI->getValue().sext(BitWidth));
uint32_t BitWidth = DestTy->getScalarSizeInBits();
return ConstantInt::get(DestTy, CI->getValue().sext(BitWidth));
}
return nullptr;
case Instruction::Trunc: {
if (V->getType()->isVectorTy())
return nullptr;

uint32_t DestBitWidth = cast<IntegerType>(DestTy)->getBitWidth();
if (ConstantInt *CI = dyn_cast<ConstantInt>(V)) {
return ConstantInt::get(V->getContext(),
CI->getValue().trunc(DestBitWidth));
uint32_t BitWidth = DestTy->getScalarSizeInBits();
return ConstantInt::get(DestTy, CI->getValue().trunc(BitWidth));
}

return nullptr;
Expand Down Expand Up @@ -807,44 +801,44 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
default:
break;
case Instruction::Add:
return ConstantInt::get(CI1->getContext(), C1V + C2V);
return ConstantInt::get(C1->getType(), C1V + C2V);
case Instruction::Sub:
return ConstantInt::get(CI1->getContext(), C1V - C2V);
return ConstantInt::get(C1->getType(), C1V - C2V);
case Instruction::Mul:
return ConstantInt::get(CI1->getContext(), C1V * C2V);
return ConstantInt::get(C1->getType(), C1V * C2V);
case Instruction::UDiv:
assert(!CI2->isZero() && "Div by zero handled above");
return ConstantInt::get(CI1->getContext(), C1V.udiv(C2V));
return ConstantInt::get(CI1->getType(), C1V.udiv(C2V));
case Instruction::SDiv:
assert(!CI2->isZero() && "Div by zero handled above");
if (C2V.isAllOnes() && C1V.isMinSignedValue())
return PoisonValue::get(CI1->getType()); // MIN_INT / -1 -> poison
return ConstantInt::get(CI1->getContext(), C1V.sdiv(C2V));
return ConstantInt::get(CI1->getType(), C1V.sdiv(C2V));
case Instruction::URem:
assert(!CI2->isZero() && "Div by zero handled above");
return ConstantInt::get(CI1->getContext(), C1V.urem(C2V));
return ConstantInt::get(C1->getType(), C1V.urem(C2V));
case Instruction::SRem:
assert(!CI2->isZero() && "Div by zero handled above");
if (C2V.isAllOnes() && C1V.isMinSignedValue())
return PoisonValue::get(CI1->getType()); // MIN_INT % -1 -> poison
return ConstantInt::get(CI1->getContext(), C1V.srem(C2V));
return PoisonValue::get(C1->getType()); // MIN_INT % -1 -> poison
return ConstantInt::get(C1->getType(), C1V.srem(C2V));
case Instruction::And:
return ConstantInt::get(CI1->getContext(), C1V & C2V);
return ConstantInt::get(C1->getType(), C1V & C2V);
case Instruction::Or:
return ConstantInt::get(CI1->getContext(), C1V | C2V);
return ConstantInt::get(C1->getType(), C1V | C2V);
case Instruction::Xor:
return ConstantInt::get(CI1->getContext(), C1V ^ C2V);
return ConstantInt::get(C1->getType(), C1V ^ C2V);
case Instruction::Shl:
if (C2V.ult(C1V.getBitWidth()))
return ConstantInt::get(CI1->getContext(), C1V.shl(C2V));
return ConstantInt::get(C1->getType(), C1V.shl(C2V));
return PoisonValue::get(C1->getType()); // too big shift is poison
case Instruction::LShr:
if (C2V.ult(C1V.getBitWidth()))
return ConstantInt::get(CI1->getContext(), C1V.lshr(C2V));
return ConstantInt::get(C1->getType(), C1V.lshr(C2V));
return PoisonValue::get(C1->getType()); // too big shift is poison
case Instruction::AShr:
if (C2V.ult(C1V.getBitWidth()))
return ConstantInt::get(CI1->getContext(), C1V.ashr(C2V));
return ConstantInt::get(C1->getType(), C1V.ashr(C2V));
return PoisonValue::get(C1->getType()); // too big shift is poison
}
}
Expand Down Expand Up @@ -877,7 +871,9 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode, Constant *C1,
return ConstantFP::get(C1->getContext(), C3V);
}
}
} else if (auto *VTy = dyn_cast<VectorType>(C1->getType())) {
}

if (auto *VTy = dyn_cast<VectorType>(C1->getType())) {
// Fast path for splatted constants.
if (Constant *C2Splat = C2->getSplatValue()) {
if (Instruction::isIntDivRem(Opcode) && C2Splat->isNullValue())
Expand Down
7 changes: 7 additions & 0 deletions llvm/lib/IR/Constants.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -441,6 +441,13 @@ Constant *Constant::getAggregateElement(unsigned Elt) const {
? CAZ->getElementValue(Elt)
: nullptr;

if (const auto *CI = dyn_cast<ConstantInt>(this))
return Elt < cast<VectorType>(getType())
->getElementCount()
.getKnownMinValue()
? ConstantInt::get(getContext(), CI->getValue())
: nullptr;

// FIXME: getNumElements() will fail for non-fixed vector types.
if (isa<ScalableVectorType>(getType()))
return nullptr;
Expand Down
1 change: 1 addition & 0 deletions llvm/test/Transforms/InstCombine/add.ll
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
; RUN: opt < %s -passes=instcombine -use-constant-int-for-fixed-length-splat -S | FileCheck %s

declare void @use(i8)
declare void @use_i1(i1)
Expand Down
1 change: 1 addition & 0 deletions llvm/test/Transforms/InstCombine/div.ll
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@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
; RUN: opt < %s -passes=instcombine -use-constant-int-for-fixed-length-splat -S | FileCheck %s

declare void @use(i32)

Expand Down
1 change: 1 addition & 0 deletions llvm/test/Transforms/InstCombine/mul.ll
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
; RUN: opt < %s -passes=instcombine -use-constant-int-for-fixed-length-splat -S | FileCheck %s

declare i32 @llvm.abs.i32(i32, i1)

Expand Down
16 changes: 11 additions & 5 deletions llvm/test/Transforms/InstCombine/or.ll
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
; RUN: opt < %s -passes=instcombine -S | FileCheck %s --check-prefixes=CHECK,CONSTVEC
; RUN: opt < %s -passes=instcombine -S -use-constant-int-for-fixed-length-splat | FileCheck %s --check-prefixes=CHECK,CONSTSPLAT

target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128-n32:64"
declare void @use(i32)
Expand Down Expand Up @@ -399,10 +400,15 @@ define i32 @test30(i32 %A) {
}

define <2 x i32> @test30vec(<2 x i32> %A) {
; CHECK-LABEL: @test30vec(
; CHECK-NEXT: [[TMP1:%.*]] = and <2 x i32> [[A:%.*]], splat (i32 -58312)
; CHECK-NEXT: [[E:%.*]] = or disjoint <2 x i32> [[TMP1]], splat (i32 32962)
; CHECK-NEXT: ret <2 x i32> [[E]]
; CONSTVEC-LABEL: @test30vec(
; CONSTVEC-NEXT: [[TMP1:%.*]] = and <2 x i32> [[A:%.*]], splat (i32 -58312)
; CONSTVEC-NEXT: [[E:%.*]] = or disjoint <2 x i32> [[TMP1]], splat (i32 32962)
; CONSTVEC-NEXT: ret <2 x i32> [[E]]
;
; CONSTSPLAT-LABEL: @test30vec(
; CONSTSPLAT-NEXT: [[D:%.*]] = and <2 x i32> [[A:%.*]], splat (i32 -58312)
; CONSTSPLAT-NEXT: [[E:%.*]] = or disjoint <2 x i32> [[D]], splat (i32 32962)
; CONSTSPLAT-NEXT: ret <2 x i32> [[E]]
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@nikic nikic Nov 11, 2024

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Is the difference here only in variable naming?

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@paulwalker-arm paulwalker-arm Nov 12, 2024

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Yes. My guess is that we're now going down a path where the original name is preserved. I was going to ignore it but then remembered how it bugs me when I run the update scripts and end up with a bunch of changes unrelated to my PR.

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@nikic nikic Nov 12, 2024

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Nowadays the update scripts are supposed to keep the check names stable even if the generated names change :)

;
%B = or <2 x i32> %A, <i32 32962, i32 32962>
%C = and <2 x i32> %A, <i32 -65536, i32 -65536>
Expand Down
1 change: 1 addition & 0 deletions llvm/test/Transforms/InstCombine/rotate.ll
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
; RUN: opt < %s -passes=instcombine -use-constant-int-for-fixed-length-splat -S | FileCheck %s

target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"

Expand Down
1 change: 1 addition & 0 deletions llvm/test/Transforms/InstCombine/shift.ll
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Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
; RUN: opt < %s -passes=instcombine -use-constant-int-for-fixed-length-splat -S | FileCheck %s

declare void @use(i64)
declare void @use_i32(i32)
Expand Down
2 changes: 2 additions & 0 deletions llvm/test/Transforms/InstCombine/xor-ashr.ll
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Original file line number Diff line number Diff line change
@@ -1,5 +1,7 @@
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt < %s -passes=instcombine -S | FileCheck %s
; RUN: opt < %s -passes=instcombine -use-constant-int-for-fixed-length-splat -S | FileCheck %s

target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"

declare void @use16(i16)
Expand Down
3 changes: 1 addition & 2 deletions llvm/test/Transforms/InstSimplify/bitcast-vector-fold.ll
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Expand Up @@ -81,8 +81,7 @@ define <1 x i1> @test10() {
; CONSTVEC-NEXT: ret <1 x i1> [[RET]]
;
; CONSTSPLAT-LABEL: @test10(
; CONSTSPLAT-NEXT: [[RET:%.*]] = icmp eq <1 x i64> splat (i64 -1), zeroinitializer
; CONSTSPLAT-NEXT: ret <1 x i1> [[RET]]
; CONSTSPLAT-NEXT: ret <1 x i1> zeroinitializer
;
%ret = icmp eq <1 x i64> <i64 bitcast (<1 x double> <double 0xFFFFFFFFFFFFFFFF> to i64)>, zeroinitializer
ret <1 x i1> %ret
Expand Down
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