One step to fixing up codegen for a=b, where a is a volatile struct.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@72315 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExprAgg.cpp b/lib/CodeGen/CGExprAgg.cpp
index 81e1a12..13559ac 100644
--- a/lib/CodeGen/CGExprAgg.cpp
+++ b/lib/CodeGen/CGExprAgg.cpp
@@ -247,7 +247,7 @@
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 @@
// 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.