From 69ba0613f2b9ae20fc00fc547fd125d52629d5a6 Mon Sep 17 00:00:00 2001 From: Haicheng Wu Date: Sat, 19 May 2018 18:00:02 +0000 Subject: [GlobalMerge] Exit early if only one global is to be merged To save some compilation time and prevent some unnecessary changes. Differential Revision: https://reviews.llvm.org/D46640 llvm-svn: 332813 --- llvm/lib/CodeGen/GlobalMerge.cpp | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) (limited to 'llvm/lib/CodeGen/GlobalMerge.cpp') diff --git a/llvm/lib/CodeGen/GlobalMerge.cpp b/llvm/lib/CodeGen/GlobalMerge.cpp index cda5861f676..fbf94d2bb7f 100644 --- a/llvm/lib/CodeGen/GlobalMerge.cpp +++ b/llvm/lib/CodeGen/GlobalMerge.cpp @@ -445,6 +445,7 @@ bool GlobalMerge::doMerge(const SmallVectorImpl &Globals, LLVM_DEBUG(dbgs() << " Trying to merge set, starts with #" << GlobalSet.find_first() << "\n"); + bool Changed = false; ssize_t i = GlobalSet.find_first(); while (i != -1) { ssize_t j = 0; @@ -469,6 +470,12 @@ bool GlobalMerge::doMerge(const SmallVectorImpl &Globals, } } + // Exit early if there is only one global to merge. + if (Tys.size() < 2) { + i = j; + continue; + } + // If merged variables doesn't have external linkage, we needn't to expose // the symbol after merging. GlobalValue::LinkageTypes Linkage = HasExternal @@ -526,10 +533,11 @@ bool GlobalMerge::doMerge(const SmallVectorImpl &Globals, NumMerged++; } + Changed = true; i = j; } - return true; + return Changed; } void GlobalMerge::collectUsedGlobalVariables(Module &M) { -- cgit v1.2.3