Author: epilk Date: Wed Feb 27 16:47:55 2019 New Revision: 355054 URL: http://llvm.org/viewvc/llvm-project?rev=355054&view=rev Log: [CodeGen] Fix some broken IR generated by -fsanitize=unsigned-integer-overflow
I think the author of the function assumed that `GetInsertBlock()` wouldn't change from where `atomicPHI` was created, but this isn't true when `-fsanitize=unsigned-integer-overflow` is enabled (we generate an overflow/continuation label). Fix by keeping track of the block we want to return to to complete the cmpxchg loop. rdar://48406558 Differential revision: https://reviews.llvm.org/D58744 Added: cfe/trunk/test/CodeGen/sanitize-atomic-int-overflow.c Modified: cfe/trunk/lib/CodeGen/CGExprScalar.cpp Modified: cfe/trunk/lib/CodeGen/CGExprScalar.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprScalar.cpp?rev=355054&r1=355053&r2=355054&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CGExprScalar.cpp (original) +++ cfe/trunk/lib/CodeGen/CGExprScalar.cpp Wed Feb 27 16:47:55 2019 @@ -2555,14 +2555,14 @@ ScalarExprEmitter::EmitScalarPrePostIncD } if (atomicPHI) { - llvm::BasicBlock *opBB = Builder.GetInsertBlock(); + llvm::BasicBlock *curBlock = Builder.GetInsertBlock(); llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn); auto Pair = CGF.EmitAtomicCompareExchange( LV, RValue::get(atomicPHI), RValue::get(value), E->getExprLoc()); llvm::Value *old = CGF.EmitToMemory(Pair.first.getScalarVal(), type); llvm::Value *success = Pair.second; - atomicPHI->addIncoming(old, opBB); - Builder.CreateCondBr(success, contBB, opBB); + atomicPHI->addIncoming(old, curBlock); + Builder.CreateCondBr(success, contBB, atomicPHI->getParent()); Builder.SetInsertPoint(contBB); return isPre ? value : input; } @@ -2909,14 +2909,14 @@ LValue ScalarExprEmitter::EmitCompoundAs Loc, ScalarConversionOpts(CGF.SanOpts)); if (atomicPHI) { - llvm::BasicBlock *opBB = Builder.GetInsertBlock(); + llvm::BasicBlock *curBlock = Builder.GetInsertBlock(); llvm::BasicBlock *contBB = CGF.createBasicBlock("atomic_cont", CGF.CurFn); auto Pair = CGF.EmitAtomicCompareExchange( LHSLV, RValue::get(atomicPHI), RValue::get(Result), E->getExprLoc()); llvm::Value *old = CGF.EmitToMemory(Pair.first.getScalarVal(), LHSTy); llvm::Value *success = Pair.second; - atomicPHI->addIncoming(old, opBB); - Builder.CreateCondBr(success, contBB, opBB); + atomicPHI->addIncoming(old, curBlock); + Builder.CreateCondBr(success, contBB, atomicPHI->getParent()); Builder.SetInsertPoint(contBB); return LHSLV; } Added: cfe/trunk/test/CodeGen/sanitize-atomic-int-overflow.c URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/sanitize-atomic-int-overflow.c?rev=355054&view=auto ============================================================================== --- cfe/trunk/test/CodeGen/sanitize-atomic-int-overflow.c (added) +++ cfe/trunk/test/CodeGen/sanitize-atomic-int-overflow.c Wed Feb 27 16:47:55 2019 @@ -0,0 +1,33 @@ +// RUN: %clang_cc1 -triple x86_64-apple-macosx10.14.0 -fsanitize=unsigned-integer-overflow %s -emit-llvm -o - | FileCheck %s + +_Atomic(unsigned) atomic; + +// CHECK-LABEL: define void @cmpd_assign +void cmpd_assign() { + // CHECK: br label %[[LOOP_START:.*]] + + // CHECK: [[LOOP_START]]: + // CHECK-NEXT: phi i32 {{.*}}, [ {{.*}}, %[[INCOMING_BLOCK:.*]] ] + + // CHECK: [[INCOMING_BLOCK]]: + // CHECK-NEXT: cmpxchg + // CHECK-NEXT: extractvalue + // CHECK-NEXT: extractvalue + // CHECK-NEXT: br i1 %8, label %{{.*}}, label %[[LOOP_START]] + atomic += 1; +} + +// CHECK-LABEL: define void @inc +void inc() { + // CHECK: br label %[[LOOP_START:.*]] + + // CHECK: [[LOOP_START]]: + // CHECK-NEXT: phi i32 {{.*}}, [ {{.*}}, %[[INCOMING_BLOCK:.*]] ] + + // CHECK: [[INCOMING_BLOCK]]: + // CHECK-NEXT: cmpxchg + // CHECK-NEXT: extractvalue + // CHECK-NEXT: extractvalue + // CHECK-NEXT: br i1 %8, label %{{.*}}, label %[[LOOP_START]] + atomic++; +} _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
