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One step to fixing up codegen for a=b, where a is a volatile struct. 

llvm-svn: 72315
This commit is contained in:
Mike Stump 2009-05-23 04:13:59 +00:00
parent 57406b2783
commit 8673657275
1 changed files with 13 additions and 1 deletions
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14
clang/lib/CodeGen/CGExprAgg.cpp
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@ -247,7 +247,7 @@ void AggExprEmitter::VisitBinAssign(const BinaryOperator *E) {
RValue::getAggregate(AggLoc));
} else {
// Codegen the RHS so that it stores directly into the LHS.
CGF.EmitAggExpr(E->getRHS(), LHS.getAddress(), false /*FIXME: VOLATILE LHS*/);
CGF.EmitAggExpr(E->getRHS(), LHS.getAddress(), LHS.isVolatileQualified());
if (DestPtr == 0)
return;
@ -519,6 +519,18 @@ void CodeGenFunction::EmitAggregateCopy(llvm::Value *DestPtr,
// FIXME: Handle variable sized types.
const llvm::Type *IntPtr = llvm::IntegerType::get(LLVMPointerWidth);
// FIXME: If we have a volatile struct, the optimizer can remove what might
// appear to be `extra' memory ops:
//
// volatile struct { int i; } a, b;
//
// int main() {
// a = b;
// a = b;
// }
//
// either, we need to use a differnt call here, or the backend needs to be
// taught to not do this.
Builder.CreateCall4(CGM.getMemCpyFn(),
DestPtr, SrcPtr,
// TypeInfo.first describes size in bits.