fhahn created this revision. fhahn added reviewers: efriedma, aprantl, arsenm. Herald added subscribers: cfe-commits, hiraditya. Herald added projects: clang, LLVM. fhahn requested review of this revision. Herald added a subscriber: wdng.
Currently ConstantExpr::getWithOperands does not handle FNeg and subsequently treats FNeg as binary operator, leading to an assertion failure or segmentation fault if built without assertions. Originally I reproduced this with llvm-dis on a bitcode file, which I unfortunately cannot share and also cannot really reduce. But PR45426 describes the same issue and has a reproducer with Clang, so I'll go with that. Repository: rG LLVM Github Monorepo https://reviews.llvm.org/D86274 Files: clang/test/CodeGen/constantexpr-fneg.c llvm/lib/IR/Constants.cpp Index: llvm/lib/IR/Constants.cpp =================================================================== --- llvm/lib/IR/Constants.cpp +++ llvm/lib/IR/Constants.cpp @@ -1441,6 +1441,8 @@ OnlyIfReducedTy); case Instruction::ExtractValue: return ConstantExpr::getExtractValue(Ops[0], getIndices(), OnlyIfReducedTy); + case Instruction::FNeg: + return ConstantExpr::getFNeg(Ops[0]); case Instruction::ShuffleVector: return ConstantExpr::getShuffleVector(Ops[0], Ops[1], getShuffleMask(), OnlyIfReducedTy); Index: clang/test/CodeGen/constantexpr-fneg.c =================================================================== --- /dev/null +++ clang/test/CodeGen/constantexpr-fneg.c @@ -0,0 +1,20 @@ +// RUN: %clang_cc1 -emit-llvm-bc -disable-llvm-passes -o %t.bc %s +// RUN: llvm-dis %t.bc -o - | FileCheck %s + +// Test case for PR45426. Make sure we do not crash while writing bitcode +// containing a simplify-able fneg constant expression. Check that the created +// bitcode file can be disassembled and has the constant expressions simplified. +// +// CHECK-LABEL define i32 @main() +// CHECK: entry: +// CHECK-NEXT: %retval = alloca i32 +// CHECK-NEXT: store i32 0, i32* %retval +// CHECK-NEXT: [[LV:%.*]] = load float*, float** @c +// CHECK-NEXT: store float 1.000000e+00, float* [[LV]], align 4 +// CHECK-NEXT: ret i32 -1 + +int a[], b; +float *c; +int main() { + return -(*c = &b != a); +}
Index: llvm/lib/IR/Constants.cpp =================================================================== --- llvm/lib/IR/Constants.cpp +++ llvm/lib/IR/Constants.cpp @@ -1441,6 +1441,8 @@ OnlyIfReducedTy); case Instruction::ExtractValue: return ConstantExpr::getExtractValue(Ops[0], getIndices(), OnlyIfReducedTy); + case Instruction::FNeg: + return ConstantExpr::getFNeg(Ops[0]); case Instruction::ShuffleVector: return ConstantExpr::getShuffleVector(Ops[0], Ops[1], getShuffleMask(), OnlyIfReducedTy); Index: clang/test/CodeGen/constantexpr-fneg.c =================================================================== --- /dev/null +++ clang/test/CodeGen/constantexpr-fneg.c @@ -0,0 +1,20 @@ +// RUN: %clang_cc1 -emit-llvm-bc -disable-llvm-passes -o %t.bc %s +// RUN: llvm-dis %t.bc -o - | FileCheck %s + +// Test case for PR45426. Make sure we do not crash while writing bitcode +// containing a simplify-able fneg constant expression. Check that the created +// bitcode file can be disassembled and has the constant expressions simplified. +// +// CHECK-LABEL define i32 @main() +// CHECK: entry: +// CHECK-NEXT: %retval = alloca i32 +// CHECK-NEXT: store i32 0, i32* %retval +// CHECK-NEXT: [[LV:%.*]] = load float*, float** @c +// CHECK-NEXT: store float 1.000000e+00, float* [[LV]], align 4 +// CHECK-NEXT: ret i32 -1 + +int a[], b; +float *c; +int main() { + return -(*c = &b != a); +}
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