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| author | Sanjay Patel <spatel@rotateright.com> | 2021-09-27 13:49:13 -0400 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2021-09-27 14:10:26 -0400 |
| commit | 623f93ed1c99904a2b092c617bb392010e7a0184 (patch) | |
| tree | 558446648b29bf4737ff6cb3f124c6e178267640 | |
| parent | d992950078efd81971b8d84a862671b17af88bff (diff) | |
| download | llvm-623f93ed1c99904a2b092c617bb392010e7a0184.tar.gz | |
[InstCombine] add use check to shl transform
This bug was introduced with the refactoring in:
9075edc89bc9
...but there were no tests to detect it.
| -rw-r--r-- | llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp | 2 | ||||
| -rw-r--r-- | llvm/test/Transforms/InstCombine/shift-shift.ll | 6 |
2 files changed, 3 insertions, 5 deletions
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp index 950d2ab6bc9f..c59c21428c69 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineShifts.cpp @@ -860,7 +860,7 @@ Instruction *InstCombinerImpl::visitShl(BinaryOperator &I) { // we have confidence that the shifts will get folded together. Instruction *TrOp; const APInt *TrShiftAmt; - if (match(Op0, m_Trunc(m_Instruction(TrOp))) && + if (match(Op0, m_OneUse(m_Trunc(m_Instruction(TrOp)))) && match(TrOp, m_OneUse(m_Shift(m_Value(), m_APInt(TrShiftAmt)))) && TrShiftAmt->ult(TrOp->getType()->getScalarSizeInBits())) { Type *SrcTy = TrOp->getType(); diff --git a/llvm/test/Transforms/InstCombine/shift-shift.ll b/llvm/test/Transforms/InstCombine/shift-shift.ll index 7c57cdf2f07f..163a39657343 100644 --- a/llvm/test/Transforms/InstCombine/shift-shift.ll +++ b/llvm/test/Transforms/InstCombine/shift-shift.ll @@ -198,8 +198,7 @@ define i8 @shl_trunc_bigger_lshr_use2(i32 %x) { ; CHECK-NEXT: [[RT:%.*]] = lshr i32 [[X:%.*]], 5 ; CHECK-NEXT: [[TR:%.*]] = trunc i32 [[RT]] to i8 ; CHECK-NEXT: call void @use8(i8 [[TR]]) -; CHECK-NEXT: [[LT1:%.*]] = shl nuw nsw i32 [[RT]], 3 -; CHECK-NEXT: [[LT:%.*]] = trunc i32 [[LT1]] to i8 +; CHECK-NEXT: [[LT:%.*]] = shl i8 [[TR]], 3 ; CHECK-NEXT: ret i8 [[LT]] ; %rt = lshr i32 %x, 5 @@ -214,8 +213,7 @@ define i8 @shl_trunc_smaller_lshr_use2(i32 %x) { ; CHECK-NEXT: [[RT:%.*]] = lshr i32 [[X:%.*]], 3 ; CHECK-NEXT: [[TR:%.*]] = trunc i32 [[RT]] to i8 ; CHECK-NEXT: call void @use8(i8 [[TR]]) -; CHECK-NEXT: [[LT1:%.*]] = shl i32 [[RT]], 5 -; CHECK-NEXT: [[LT:%.*]] = trunc i32 [[LT1]] to i8 +; CHECK-NEXT: [[LT:%.*]] = shl i8 [[TR]], 5 ; CHECK-NEXT: ret i8 [[LT]] ; %rt = lshr i32 %x, 3 |