From 25312b2b6c945e1cd236dc679b174114d96d840e Mon Sep 17 00:00:00 2001 From: David Green Date: Wed, 6 Jun 2018 14:48:32 +0000 Subject: [GlobalMerge] Set the alignment on merged global structs If no alignment is set, the abi/preferred alignment of structs will be used which may be higher than required. This can lead to extra padding and in the end an increase in data size. Differential Revision: https://reviews.llvm.org/D47633 llvm-svn: 334099 --- llvm/lib/CodeGen/GlobalMerge.cpp | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'llvm/lib/CodeGen/GlobalMerge.cpp') diff --git a/llvm/lib/CodeGen/GlobalMerge.cpp b/llvm/lib/CodeGen/GlobalMerge.cpp index fbf94d2bb7f..bebf1d6d4cd 100644 --- a/llvm/lib/CodeGen/GlobalMerge.cpp +++ b/llvm/lib/CodeGen/GlobalMerge.cpp @@ -500,6 +500,11 @@ bool GlobalMerge::doMerge(const SmallVectorImpl &Globals, GlobalVariable::NotThreadLocal, AddrSpace); const StructLayout *MergedLayout = DL.getStructLayout(MergedTy); + // Set the alignment of the merged struct as the maximum alignment of the + // globals to prevent over-alignment. We don't handle globals that are not + // default aligned, so the alignment of the MergedLayout struct is + // equivalent. + MergedGV->setAlignment(MergedLayout->getAlignment()); for (ssize_t k = i, idx = 0; k != j; k = GlobalSet.find_next(k), ++idx) { GlobalValue::LinkageTypes Linkage = Globals[k]->getLinkage(); -- cgit v1.2.3