IRgen: Reapply r128691 with a fix to ensure we don't increase alignment past
that of the array element type.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@128698 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExpr.cpp b/lib/CodeGen/CGExpr.cpp
index ab88a38..92e6a19 100644
--- a/lib/CodeGen/CGExpr.cpp
+++ b/lib/CodeGen/CGExpr.cpp
@@ -1424,6 +1424,7 @@
// We know that the pointer points to a type of the correct size, unless the
// size is a VLA or Objective-C interface.
llvm::Value *Address = 0;
+ unsigned ArrayAlignment = 0;
if (const VariableArrayType *VAT =
getContext().getAsVariableArrayType(E->getType())) {
llvm::Value *VLASize = GetVLASize(VAT);
@@ -1459,10 +1460,14 @@
// "gep x, i" here. Emit one "gep A, 0, i".
assert(Array->getType()->isArrayType() &&
"Array to pointer decay must have array source type!");
- llvm::Value *ArrayPtr = EmitLValue(Array).getAddress();
+ LValue ArrayLV = EmitLValue(Array);
+ llvm::Value *ArrayPtr = ArrayLV.getAddress();
llvm::Value *Zero = llvm::ConstantInt::get(Int32Ty, 0);
llvm::Value *Args[] = { Zero, Idx };
+ // Propagate the alignment from the array itself to the result.
+ ArrayAlignment = ArrayLV.getAlignment();
+
if (getContext().getLangOptions().isSignedOverflowDefined())
Address = Builder.CreateGEP(ArrayPtr, Args, Args+2, "arrayidx");
else
@@ -1480,7 +1485,13 @@
assert(!T.isNull() &&
"CodeGenFunction::EmitArraySubscriptExpr(): Illegal base type");
- LValue LV = MakeAddrLValue(Address, T);
+ // Limit the alignment to that of the result type.
+ if (ArrayAlignment) {
+ unsigned Align = getContext().getTypeAlignInChars(T).getQuantity();
+ ArrayAlignment = std::min(Align, ArrayAlignment);
+ }
+
+ LValue LV = MakeAddrLValue(Address, T, ArrayAlignment);
LV.getQuals().setAddressSpace(E->getBase()->getType().getAddressSpace());
if (getContext().getLangOptions().ObjC1 &&