From 102846714a88538554c7ff69773140152e6135e9 Mon Sep 17 00:00:00 2001 From: Evgeniy Stepanov Date: Thu, 31 Jan 2013 09:53:29 +0000 Subject: [PATCH] [msan] Run more optimizations after MemorySanitizer pass. MSan instrumentation is driven by the original code. We take every incoming instruction and emit another instruction (or ten) next to it, operating on the shadow values (but sometimes on the real values, too). Two programs in one, essentially. There can be any kinds of redundancies in the second one, so we just run whatever is normally run at -O2, and then exclude some passes that do not help much with benchmarks. llvm-svn: 174049 --- clang/lib/CodeGen/BackendUtil.cpp | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/clang/lib/CodeGen/BackendUtil.cpp b/clang/lib/CodeGen/BackendUtil.cpp index 6d42df59b41b..1d5ff44a50be 100644 --- a/clang/lib/CodeGen/BackendUtil.cpp +++ b/clang/lib/CodeGen/BackendUtil.cpp @@ -184,6 +184,18 @@ static void addMemorySanitizerPass(const PassManagerBuilder &Builder, const CodeGenOptions &CGOpts = BuilderWrapper.getCGOpts(); PM.add(createMemorySanitizerPass(CGOpts.SanitizeMemoryTrackOrigins, CGOpts.SanitizerBlacklistFile)); + + // MemorySanitizer inserts complex instrumentation that mostly follows + // the logic of the original code, but operates on "shadow" values. + // It can benefit from re-running some general purpose optimization passes. + if (Builder.OptLevel > 0) { + PM.add(createEarlyCSEPass()); + PM.add(createReassociatePass()); + PM.add(createLICMPass()); + PM.add(createGVNPass()); + PM.add(createInstructionCombiningPass()); + PM.add(createDeadStoreEliminationPass()); + } } static void addThreadSanitizerPass(const PassManagerBuilder &Builder, -- GitLab