PR12848: When emitting a local variable declared 'constexpr', always initialize it with a store or a memcpy, not by emitting the initializer expression. This is not required for correctness, but more closely aligns with people's expectations, and is cheap (since we've already evaluated the initializer).
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@183082 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index 9741f58..4b19b54 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -840,19 +840,19 @@
bool NRVO = getLangOpts().ElideConstructors &&
D.isNRVOVariable();
- // If this value is a POD array or struct with a statically
- // determinable constant initializer, there are optimizations we can do.
+ // If this value is an array or struct with a statically determinable
+ // constant initializer, there are optimizations we can do.
//
// TODO: We should constant-evaluate the initializer of any variable,
// as long as it is initialized by a constant expression. Currently,
// isConstantInitializer produces wrong answers for structs with
// reference or bitfield members, and a few other cases, and checking
// for POD-ness protects us from some of these.
- if (D.getInit() &&
- (Ty->isArrayType() || Ty->isRecordType()) &&
- (Ty.isPODType(getContext()) ||
- getContext().getBaseElementType(Ty)->isObjCObjectPointerType()) &&
- D.getInit()->isConstantInitializer(getContext(), false)) {
+ if (D.getInit() && (Ty->isArrayType() || Ty->isRecordType()) &&
+ (D.isConstexpr() ||
+ ((Ty.isPODType(getContext()) ||
+ getContext().getBaseElementType(Ty)->isObjCObjectPointerType()) &&
+ D.getInit()->isConstantInitializer(getContext(), false)))) {
// If the variable's a const type, and it's neither an NRVO
// candidate nor a __block variable and has no mutable members,
@@ -1080,7 +1080,7 @@
capturedByInit ? emission.Address : emission.getObjectAddress(*this);
llvm::Constant *constant = 0;
- if (emission.IsConstantAggregate) {
+ if (emission.IsConstantAggregate || D.isConstexpr()) {
assert(!capturedByInit && "constant init contains a capturing block?");
constant = CGM.EmitConstantInit(D, this);
}
@@ -1091,6 +1091,13 @@
return EmitExprAsInit(Init, &D, lv, capturedByInit);
}
+ if (!emission.IsConstantAggregate) {
+ // For simple scalar/complex initialization, store the value directly.
+ LValue lv = MakeAddrLValue(Loc, type, alignment);
+ lv.setNonGC(true);
+ return EmitStoreThroughLValue(RValue::get(constant), lv, true);
+ }
+
// If this is a simple aggregate initialization, we can optimize it
// in various ways.
bool isVolatile = type.isVolatileQualified();