[GMR] Add a late run of GlobalsModRef to the main pass pipeline behind

the general GMR-in-non-LTO flag.

Without this, we have the global information during the CGSCC pipeline
for GVN and such, but don't have it available during the late loop
optimizations such as the vectorizer. Moreover, after the CGSCC pipeline
has finished we have substantially more accurate and refined call graph
information, function annotations, etc, which will make GMR even more
powerful than it is early in the pipelien.

Note that we have to play silly games with preserving AliasAnalysis
(which is now trivially preserved) in order to let a module analysis
magically be preserved into the entire function pass pipeline.
Simultaneously we have to not make GMR an immutable pass in order to be
able to re-run it and collect fresh data on the final call graph.

llvm-svn: 242999

1 files changed, 2 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/Scalar/LoopRotation.cpp b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
index a675e1289ba..bf034bc8d19 100644
--- a/llvm/lib/Transforms/Scalar/LoopRotation.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopRotation.cpp
@@ -13,6 +13,7 @@
 
 #include "llvm/Transforms/Scalar.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/Analysis/AssumptionCache.h"
 #include "llvm/Analysis/CodeMetrics.h"
 #include "llvm/Analysis/InstructionSimplify.h"
@@ -56,6 +57,7 @@ namespace {
 
     // LCSSA form makes instruction renaming easier.
     void getAnalysisUsage(AnalysisUsage &AU) const override {
+      AU.addPreserved<AliasAnalysis>();
       AU.addRequired<AssumptionCacheTracker>();
       AU.addPreserved<DominatorTreeWrapperPass>();
       AU.addRequired<LoopInfoWrapperPass>();