[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
llvm-svn: 355054
diff --git a/clang/lib/CodeGen/CGExprScalar.cpp b/clang/lib/CodeGen/CGExprScalar.cpp
index bdc07f1..e831c82 100644
--- a/clang/lib/CodeGen/CGExprScalar.cpp
+++ b/clang/lib/CodeGen/CGExprScalar.cpp
@@ -2555,14 +2555,14 @@
}
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 @@
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;
}