[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

diff --git a/llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp b/llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp
index c9924984bb572a8ba64716bd999a7dc00b0cf40c..b59ddcffeff50e357fc7b10992bf6b48f1827d17 100644 (file)
--- 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;
 }
 }

diff --git a/llvm/test/Transforms/InstCombine/pr30929.ll b/llvm/test/Transforms/InstCombine/pr30929.ll
new file mode 100644 (file)
index 0000000..2d19775
--- /dev/null
+++ b/llvm/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)