Unrevert r147271, reverted in r147361.

Also temporarily remove the assumption from IR gen that we can emit IR for every
constant we can fold, since it isn't currently true in C++11, to fix PR11676.

Original comment from r147271:

constexpr: perform zero-initialization prior to / instead of performing a
constructor call when appropriate. Thanks to Eli for spotting this.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@147384 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 7 insertions, 6 deletions

diff --git a/lib/CodeGen/CGDecl.cpp b/lib/CodeGen/CGDecl.cpp
index e8f00e7dde..43077cefa0 100644
--- a/lib/CodeGen/CGDecl.cpp
+++ b/lib/CodeGen/CGDecl.cpp
@@ -970,7 +970,13 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
   llvm::Value *Loc =
     capturedByInit ? emission.Address : emission.getObjectAddress(*this);
 
-  if (!emission.IsConstantAggregate) {
+  llvm::Constant *constant = 0;
+  if (emission.IsConstantAggregate) {
+    assert(!capturedByInit && "constant init contains a capturing block?");
+    constant = CGM.EmitConstantExpr(D.getInit(), type, this);
+  }
+
+  if (!constant) {
     LValue lv = MakeAddrLValue(Loc, type, alignment);
     lv.setNonGC(true);
     return EmitExprAsInit(Init, &D, lv, capturedByInit);
@@ -978,13 +984,8 @@ void CodeGenFunction::EmitAutoVarInit(const AutoVarEmission &emission) {
 
   // If this is a simple aggregate initialization, we can optimize it
   // in various ways.
-  assert(!capturedByInit && "constant init contains a capturing block?");
-
   bool isVolatile = type.isVolatileQualified();
 
-  llvm::Constant *constant = CGM.EmitConstantExpr(D.getInit(), type, this);
-  assert(constant != 0 && "Wasn't a simple constant init?");
-
   llvm::Value *SizeVal =
     llvm::ConstantInt::get(IntPtrTy,
                            getContext().getTypeSizeInChars(type).getQuantity());