diff options
| author | Nikita Popov <npopov@redhat.com> | 2023-11-08 14:10:39 +0100 |
|---|---|---|
| committer | Nikita Popov <npopov@redhat.com> | 2023-11-08 14:49:24 +0100 |
| commit | d687057de8babc215d1cc883514085704ede5ab4 (patch) | |
| tree | e564b53d13e28b900e49fa0dff9b8969d10a0c70 | |
| parent | dc2cfd0407ae9b3f2c625b20bb90b62153edfebe (diff) | |
[CVP] Try to fold sdiv to constant
If we know that the sdiv result is a single constant, directly
use that instead of performing narrowing.
Fixes https://github.com/llvm/llvm-project/issues/71659.
| -rw-r--r-- | llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp | 7 | ||||
| -rw-r--r-- | llvm/test/Transforms/CorrelatedValuePropagation/sdiv.ll | 17 |
2 files changed, 10 insertions, 14 deletions
diff --git a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp index 99b4628cc68d..d58ea126f294 100644 --- a/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp +++ b/llvm/lib/Transforms/Scalar/CorrelatedValuePropagation.cpp @@ -910,6 +910,13 @@ static bool processSDiv(BinaryOperator *SDI, const ConstantRange &LCR, assert(SDI->getOpcode() == Instruction::SDiv); assert(!SDI->getType()->isVectorTy()); + // Check whether the division folds to a constant. + if (const APInt *Elem = LCR.sdiv(RCR).getSingleElement()) { + SDI->replaceAllUsesWith(ConstantInt::get(SDI->getType(), *Elem)); + SDI->eraseFromParent(); + return true; + } + struct Operand { Value *V; Domain D; diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/sdiv.ll b/llvm/test/Transforms/CorrelatedValuePropagation/sdiv.ll index 470e99d31ef8..d88fe358a0aa 100644 --- a/llvm/test/Transforms/CorrelatedValuePropagation/sdiv.ll +++ b/llvm/test/Transforms/CorrelatedValuePropagation/sdiv.ll @@ -638,10 +638,7 @@ define void @sdiv_zero(ptr %p, i32 %arg) { ; CHECK-NEXT: [[ADD:%.*]] = add i32 [[ARG:%.*]], 5 ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[ADD]], 11 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) -; CHECK-NEXT: [[DIV_LHS_TRUNC:%.*]] = trunc i32 [[ARG]] to i8 -; CHECK-NEXT: [[DIV1:%.*]] = sdiv i8 [[DIV_LHS_TRUNC]], 6 -; CHECK-NEXT: [[DIV_SEXT:%.*]] = sext i8 [[DIV1]] to i32 -; CHECK-NEXT: store i32 [[DIV_SEXT]], ptr [[P:%.*]], align 4 +; CHECK-NEXT: store i32 0, ptr [[P:%.*]], align 4 ; CHECK-NEXT: ret void ; %add = add i32 %arg, 5 @@ -676,10 +673,7 @@ define void @sdiv_pos(ptr %p, i32 %arg) { ; CHECK-NEXT: [[ADD:%.*]] = add i32 [[ARG:%.*]], -12 ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[ADD]], 6 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) -; CHECK-NEXT: [[DIV1_LHS_TRUNC:%.*]] = trunc i32 [[ARG]] to i8 -; CHECK-NEXT: [[DIV12:%.*]] = udiv i8 [[DIV1_LHS_TRUNC]], 6 -; CHECK-NEXT: [[DIV1_ZEXT:%.*]] = zext i8 [[DIV12]] to i32 -; CHECK-NEXT: store i32 [[DIV1_ZEXT]], ptr [[P:%.*]], align 4 +; CHECK-NEXT: store i32 2, ptr [[P:%.*]], align 4 ; CHECK-NEXT: ret void ; %add = add i32 %arg, -12 @@ -695,12 +689,7 @@ define void @sdiv_neg(ptr %p, i32 %arg) { ; CHECK-NEXT: [[ADD:%.*]] = add i32 [[ARG:%.*]], 17 ; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[ADD]], 6 ; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]]) -; CHECK-NEXT: [[ARG_NONNEG:%.*]] = sub i32 0, [[ARG]] -; CHECK-NEXT: [[DIV1_LHS_TRUNC:%.*]] = trunc i32 [[ARG_NONNEG]] to i8 -; CHECK-NEXT: [[DIV12:%.*]] = udiv i8 [[DIV1_LHS_TRUNC]], 6 -; CHECK-NEXT: [[DIV1_ZEXT:%.*]] = zext i8 [[DIV12]] to i32 -; CHECK-NEXT: [[DIV1_NEG:%.*]] = sub i32 0, [[DIV1_ZEXT]] -; CHECK-NEXT: store i32 [[DIV1_NEG]], ptr [[P:%.*]], align 4 +; CHECK-NEXT: store i32 -2, ptr [[P:%.*]], align 4 ; CHECK-NEXT: ret void ; %add = add i32 %arg, 17 |