[llvm] r286271 - [LibcallsShrinkWrap] This pass doesn't preserve the CFG.

[Davide Italiano via llvm-commits]

Author: davide
Date: Tue Nov  8 13:18:20 2016
New Revision: 286271

URL: http://llvm.org/viewvc/llvm-project?rev=286271&view=rev
Log:
[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

Added:
    llvm/trunk/test/Transforms/InstCombine/pr30929.ll
Modified:
    llvm/trunk/lib/Transforms/Utils/LibCallsShrinkWrap.cpp

Modified: llvm/trunk/lib/Transforms/Utils/LibCallsShrinkWrap.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LibCallsShrinkWrap.cpp?rev=286271&r1=286270&r2=286271&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LibCallsShrinkWrap.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LibCallsShrinkWrap.cpp Tue Nov  8 13:18:20 2016
@@ -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(CallIns
 }
 
 void LibCallsShrinkWrapLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
-  AU.setPreservesCFG();
+  AU.addPreserved<GlobalsAAWrapperPass>();
   AU.addRequired<TargetLibraryInfoWrapperPass>();
 }
 
@@ -561,6 +562,8 @@ PreservedAnalyses LibCallsShrinkWrapPass
   bool Changed = runImpl(F, TLI);
   if (!Changed)
     return PreservedAnalyses::all();
-  return PreservedAnalyses::none();
+  auto PA = PreservedAnalyses();
+  PA.preserve<GlobalsAA>();
+  return PA;
 }
 }

Added: llvm/trunk/test/Transforms/InstCombine/pr30929.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/pr30929.ll?rev=286271&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/pr30929.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/pr30929.ll Tue Nov  8 13:18:20 2016
@@ -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)