From: Davide Italiano <davide@freebsd.org>
Date: Tue, 8 Nov 2016 19:18:20 +0000 (+0000)
Subject: [LibcallsShrinkWrap] This pass doesn't preserve the CFG.
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=9579593784788024d58c09c9a251c78bc8c11b03;p=llvm

[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@286271 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Utils/LibCallsShrinkWrap.cpp b/lib/Transforms/Utils/LibCallsShrinkWrap.cpp
index c9924984bb5..b59ddcffeff 100644
--- a/lib/Transforms/Utils/LibCallsShrinkWrap.cpp
+++ b/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;
 }
 }
diff --git a/test/Transforms/InstCombine/pr30929.ll b/test/Transforms/InstCombine/pr30929.ll
new file mode 100644
index 00000000000..2d19775f312
--- /dev/null
+++ b/test/Transforms/InstCombine/pr30929.ll
@@ -0,0 +1,11 @@
+; We need this pipeline because to trigger dominator info verification
+; we have to compute the dominator before libcalls-shrinkwrap and
+; have a pass which requires the dominator tree after.
+; RUN: opt -domtree -libcalls-shrinkwrap -instcombine -verify-dom-info %s
+
+define void @main() {
+  %_tmp31 = call float @acosf(float 2.000000e+00)
+  ret void
+}
+
+declare float @acosf(float)