When we choose to use zeroinitializer for a trailing portion of an array
constant, don't convert the rest into a packed struct.
If an array constant has a large non-zero portion and a large zero
portion, we want to emit the first part as an array and the rest as a
zeroinitializer if possible. This fixes a memory usage regression from
r333141 when compiling PHP.
llvm-svn: 337498
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index b26ff3d..afe2bfe 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -659,7 +659,19 @@
if (TrailingZeroes >= 8) {
assert(Elements.size() >= NonzeroLength &&
"missing initializer for non-zero element");
- Elements.resize(NonzeroLength + 1);
+
+ // If all the elements had the same type up to the trailing zeroes, emit a
+ // struct of two arrays (the nonzero data and the zeroinitializer).
+ if (CommonElementType && NonzeroLength >= 8) {
+ llvm::Constant *Initial = llvm::ConstantArray::get(
+ llvm::ArrayType::get(CommonElementType, ArrayBound),
+ makeArrayRef(Elements).take_front(NonzeroLength));
+ Elements.resize(2);
+ Elements[0] = Initial;
+ } else {
+ Elements.resize(NonzeroLength + 1);
+ }
+
auto *FillerType =
CommonElementType
? CommonElementType