[LibcallsShrinkWrap] This pass doesn't preserve the CFG.

For example, it invalidates the domtree, causing assertions
in later passes which need dominator infos. Make it preserve
GlobalsAA, as suggested by Eli.

Differential Revision:  https://reviews.llvm.org/D26381

llvm-svn: 286271

1 files changed, 5 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp b/llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp
index c9924984bb5..b59ddcffeff 100644
--- a/llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp
+++ b/llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp
@@ -29,6 +29,7 @@
 #include "llvm/Transforms/Utils/LibCallsShrinkWrap.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/IR/CFG.h"
 #include "llvm/IR/Constants.h"
@@ -529,7 +530,7 @@ bool LibCallsShrinkWrap::perform(CallInst *CI) {
 }
 
 void LibCallsShrinkWrapLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.setPreservesCFG();
+  AU.addPreserved<GlobalsAAWrapperPass>();
   AU.addRequired<TargetLibraryInfoWrapperPass>();
 }
 
@@ -561,6 +562,8 @@ PreservedAnalyses LibCallsShrinkWrapPass::run(Function &F,
   bool Changed = runImpl(F, TLI);
   if (!Changed)
     return PreservedAnalyses::all();
-  return PreservedAnalyses::none();
+  auto PA = PreservedAnalyses();
+  PA.preserve<GlobalsAA>();
+  return PA;
 }
 }