Hi,
this is a fix for PR11905.
The current behaviour when generation a function prolog for arguments
of coerced types is to allocate a stack temp of the real argument type
and store the argument(s) there. This is wrong, because storage size
of the coerce-to type can be larger than that of the real type.
The new behaviour is to allocate a temp of the coerced type, copy it,
and then reference through a bitcasted pointer of the real type.
Please review.
Index: test/CodeGenObjCXX/copy.mm
===================================================================
--- test/CodeGenObjCXX/copy.mm (revision 149603)
+++ test/CodeGenObjCXX/copy.mm (working copy)
@@ -9,7 +9,7 @@
// CHECK: define [[A:%.*]]* @_ZN5test04testENS_1AE(
// CHECK: alloca
- // CHECK-NEXT: getelementptr
+ // CHECK-NEXT: bitcast
// CHECK-NEXT: store
// CHECK-NEXT: call noalias i8* @_Znwm(
// CHECK-NEXT: bitcast
Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp (revision 149603)
+++ lib/CodeGen/CGCall.cpp (working copy)
@@ -1013,7 +1013,8 @@
break;
}
- llvm::AllocaInst *Alloca = CreateMemTemp(Ty, "coerce");
+ llvm::AllocaInst *Alloca =
+ CreateTempAlloca(ArgI.getCoerceToType(), Arg->getName());
// The alignment we need to use is the max of the requested alignment for
// the argument plus the alignment required by our access code below.
@@ -1023,9 +1024,11 @@
(unsigned)getContext().getDeclAlign(Arg).getQuantity());
Alloca->setAlignment(AlignmentToUse);
- llvm::Value *V = Alloca;
- llvm::Value *Ptr = V; // Pointer to store into.
+ llvm::Value *Ptr = Alloca; // Pointer to store into.
+ llvm::Value* V = Builder.CreateBitCast(Ptr,
+ llvm::PointerType::getUnqual(ConvertTypeForMem(Ty)));
+
// If the value is offset in memory, apply the offset now.
if (unsigned Offs = ArgI.getDirectOffset()) {
Ptr = Builder.CreateBitCast(Ptr, Builder.getInt8PtrTy());
@@ -1039,7 +1042,6 @@
// and the optimizer generally likes scalar values better than FCAs.
if (llvm::StructType *STy =
dyn_cast<llvm::StructType>(ArgI.getCoerceToType())) {
- Ptr = Builder.CreateBitCast(Ptr, llvm::PointerType::getUnqual(STy));
for (unsigned i = 0, e = STy->getNumElements(); i != e; ++i) {
assert(AI != Fn->arg_end() && "Argument mismatch!");
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