Add an option to turn off the expensive GVN load PRE part of GVN.

llvm-svn: 153902

1 files changed, 5 insertions, 4 deletions

diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index 243ba1a85bf..a1b0a4580bf 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -207,7 +207,8 @@ void PassManagerBuilder::populateModulePassManager(PassManagerBase &MPM) {
 
 void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
                                                 bool Internalize,
-                                                bool RunInliner) {
+                                                bool RunInliner,
+                                                bool DisableGVNLoadPRE) {
   // Provide AliasAnalysis services for optimizations.
   addInitialAliasAnalysisPasses(PM);
 
@@ -263,9 +264,9 @@ void PassManagerBuilder::populateLTOPassManager(PassManagerBase &PM,
   PM.add(createFunctionAttrsPass()); // Add nocapture.
   PM.add(createGlobalsModRefPass()); // IP alias analysis.
 
-  PM.add(createLICMPass());      // Hoist loop invariants.
-  PM.add(createGVNPass());       // Remove redundancies.
-  PM.add(createMemCpyOptPass()); // Remove dead memcpys.
+  PM.add(createLICMPass());                 // Hoist loop invariants.
+  PM.add(createGVNPass(DisableGVNLoadPRE)); // Remove redundancies.
+  PM.add(createMemCpyOptPass());            // Remove dead memcpys.
   // Nuke dead stores.
   PM.add(createDeadStoreEliminationPass());