From 41aefe5a093de5699fa6483bdd31a737e938fb0b Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Fri, 18 Oct 2024 20:10:49 +0800 Subject: [PATCH 1/2] [InstCombine] Add pre-commit tests. NFC. --- .../InstCombine/sub-of-negatible.ll | 42 +++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/llvm/test/Transforms/InstCombine/sub-of-negatible.ll b/llvm/test/Transforms/InstCombine/sub-of-negatible.ll index b19eae4d8f9a4..83c70d62b3aed 100644 --- a/llvm/test/Transforms/InstCombine/sub-of-negatible.ll +++ b/llvm/test/Transforms/InstCombine/sub-of-negatible.ll @@ -1374,6 +1374,48 @@ define i8 @negate_select_of_op_vs_negated_op(i8 %x, i8 %y, i1 %c) { %t2 = sub i8 %y, %t1 ret i8 %t2 } + +define i8 @negate_select_of_op_vs_negated_op_nsw(i8 %x, i8 %y, i1 %c) { +; CHECK-LABEL: @negate_select_of_op_vs_negated_op_nsw( +; CHECK-NEXT: [[T0:%.*]] = sub nsw i8 0, [[X:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 [[X]], i8 [[T0]] +; CHECK-NEXT: [[T2:%.*]] = add i8 [[TMP1]], [[Y:%.*]] +; CHECK-NEXT: ret i8 [[T2]] +; + %t0 = sub nsw i8 0, %x + %t1 = select i1 %c, i8 %t0, i8 %x + %t2 = sub i8 %y, %t1 + ret i8 %t2 +} + +define i8 @negate_select_of_op_vs_negated_op_nsw_commuted(i8 %x, i8 %y, i1 %c) { +; CHECK-LABEL: @negate_select_of_op_vs_negated_op_nsw_commuted( +; CHECK-NEXT: [[T0:%.*]] = sub nsw i8 0, [[X:%.*]] +; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 [[T0]], i8 [[X]] +; CHECK-NEXT: [[T2:%.*]] = add i8 [[TMP1]], [[Y:%.*]] +; CHECK-NEXT: ret i8 [[T2]] +; + %t0 = sub nsw i8 0, %x + %t1 = select i1 %c, i8 %x, i8 %t0 + %t2 = sub i8 %y, %t1 + ret i8 %t2 +} + +define i8 @negate_select_of_op_vs_negated_op_nsw_xyyx(i8 %x, i8 %y, i8 %z, i1 %c) { +; CHECK-LABEL: @negate_select_of_op_vs_negated_op_nsw_xyyx( +; CHECK-NEXT: [[SUB1:%.*]] = sub nsw i8 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[SUB2:%.*]] = sub nsw i8 [[Y]], [[X]] +; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 [[SUB2]], i8 [[SUB1]] +; CHECK-NEXT: [[T2:%.*]] = add i8 [[TMP1]], [[Z:%.*]] +; CHECK-NEXT: ret i8 [[T2]] +; + %sub1 = sub nsw i8 %x, %y + %sub2 = sub nsw i8 %y, %x + %t1 = select i1 %c, i8 %sub1, i8 %sub2 + %t2 = sub i8 %z, %t1 + ret i8 %t2 +} + define i8 @dont_negate_ordinary_select(i8 %x, i8 %y, i8 %z, i1 %c) { ; CHECK-LABEL: @dont_negate_ordinary_select( ; CHECK-NEXT: [[T0:%.*]] = select i1 [[C:%.*]], i8 [[X:%.*]], i8 [[Y:%.*]] From 8d86a537ad756e31832eab67371179e881452fb5 Mon Sep 17 00:00:00 2001 From: Yingwei Zheng Date: Fri, 18 Oct 2024 20:19:53 +0800 Subject: [PATCH 2/2] [InstCombine] Drop nsw in negation of select --- .../lib/Transforms/InstCombine/InstCombineNegator.cpp | 11 +++++++++++ llvm/test/Transforms/InstCombine/sub-of-negatible.ll | 8 ++++---- 2 files changed, 15 insertions(+), 4 deletions(-) diff --git a/llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp b/llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp index 92293ef401465..1d7ab84f19bd5 100644 --- a/llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp +++ b/llvm/lib/Transforms/InstCombine/InstCombineNegator.cpp @@ -334,6 +334,17 @@ std::array Negator::getSortedOperandsOfBinOp(Instruction *I) { NewSelect->swapValues(); // Don't swap prof metadata, we didn't change the branch behavior. NewSelect->setName(I->getName() + ".neg"); + // Poison-generating flags should be dropped + Value *TV = NewSelect->getTrueValue(); + Value *FV = NewSelect->getFalseValue(); + if (match(TV, m_Neg(m_Specific(FV)))) + cast(TV)->dropPoisonGeneratingFlags(); + else if (match(FV, m_Neg(m_Specific(TV)))) + cast(FV)->dropPoisonGeneratingFlags(); + else { + cast(TV)->dropPoisonGeneratingFlags(); + cast(FV)->dropPoisonGeneratingFlags(); + } Builder.Insert(NewSelect); return NewSelect; } diff --git a/llvm/test/Transforms/InstCombine/sub-of-negatible.ll b/llvm/test/Transforms/InstCombine/sub-of-negatible.ll index 83c70d62b3aed..533db3144630e 100644 --- a/llvm/test/Transforms/InstCombine/sub-of-negatible.ll +++ b/llvm/test/Transforms/InstCombine/sub-of-negatible.ll @@ -1377,7 +1377,7 @@ define i8 @negate_select_of_op_vs_negated_op(i8 %x, i8 %y, i1 %c) { define i8 @negate_select_of_op_vs_negated_op_nsw(i8 %x, i8 %y, i1 %c) { ; CHECK-LABEL: @negate_select_of_op_vs_negated_op_nsw( -; CHECK-NEXT: [[T0:%.*]] = sub nsw i8 0, [[X:%.*]] +; CHECK-NEXT: [[T0:%.*]] = sub i8 0, [[X:%.*]] ; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 [[X]], i8 [[T0]] ; CHECK-NEXT: [[T2:%.*]] = add i8 [[TMP1]], [[Y:%.*]] ; CHECK-NEXT: ret i8 [[T2]] @@ -1390,7 +1390,7 @@ define i8 @negate_select_of_op_vs_negated_op_nsw(i8 %x, i8 %y, i1 %c) { define i8 @negate_select_of_op_vs_negated_op_nsw_commuted(i8 %x, i8 %y, i1 %c) { ; CHECK-LABEL: @negate_select_of_op_vs_negated_op_nsw_commuted( -; CHECK-NEXT: [[T0:%.*]] = sub nsw i8 0, [[X:%.*]] +; CHECK-NEXT: [[T0:%.*]] = sub i8 0, [[X:%.*]] ; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 [[T0]], i8 [[X]] ; CHECK-NEXT: [[T2:%.*]] = add i8 [[TMP1]], [[Y:%.*]] ; CHECK-NEXT: ret i8 [[T2]] @@ -1403,8 +1403,8 @@ define i8 @negate_select_of_op_vs_negated_op_nsw_commuted(i8 %x, i8 %y, i1 %c) { define i8 @negate_select_of_op_vs_negated_op_nsw_xyyx(i8 %x, i8 %y, i8 %z, i1 %c) { ; CHECK-LABEL: @negate_select_of_op_vs_negated_op_nsw_xyyx( -; CHECK-NEXT: [[SUB1:%.*]] = sub nsw i8 [[X:%.*]], [[Y:%.*]] -; CHECK-NEXT: [[SUB2:%.*]] = sub nsw i8 [[Y]], [[X]] +; CHECK-NEXT: [[SUB1:%.*]] = sub i8 [[X:%.*]], [[Y:%.*]] +; CHECK-NEXT: [[SUB2:%.*]] = sub i8 [[Y]], [[X]] ; CHECK-NEXT: [[TMP1:%.*]] = select i1 [[C:%.*]], i8 [[SUB2]], i8 [[SUB1]] ; CHECK-NEXT: [[T2:%.*]] = add i8 [[TMP1]], [[Z:%.*]] ; CHECK-NEXT: ret i8 [[T2]]