Avoid calls to dumpPassInfo and RegionBase<Tr>::getNameStr() in RGPassManager if

-debug-pass is not specified, as the string is only used when dumping pass
information.  There is a big cost of determining the name in
ReginBase<Tr>:getNameStr() if the region's entry or exit block doesn't have a
name.  This is the case for the Release build, as names are not preserved by the
front-end.

RegionPass is mainly used by Polly, resulting in long compile time for one file
of a customer application with the Release build (1m24s) vs Release+Asserts
build (10s) when Polly is used.  With this change, the compile time with the
Release build went down to 8s.

Patch by Sanjin Sijaric <ssijaric@codeaurora.org>!
Phabricator: http://reviews.llvm.org/D8076

llvm-svn: 231485

llvm/lib/Analysis/RegionPass.cpp

@@ -83,9 +83,11 @@ bool RGPassManager::runOnFunction(Function &F) {
     for (unsigned Index = 0; Index < getNumContainedPasses(); ++Index) {
       RegionPass *P = (RegionPass*)getContainedPass(Index);
 
+      if (isPassDebuggingExecutionsOrMore()) {
         dumpPassInfo(P, EXECUTION_MSG, ON_REGION_MSG,
                      CurrentRegion->getNameStr());
         dumpRequiredSet(P);
+      }
 
       initializeAnalysisImpl(P);
 
@@ -96,11 +98,13 @@ bool RGPassManager::runOnFunction(Function &F) {
         Changed |= P->runOnRegion(CurrentRegion, *this);
       }
 
+      if (isPassDebuggingExecutionsOrMore()) {
         if (Changed)
           dumpPassInfo(P, MODIFICATION_MSG, ON_REGION_MSG,
                        skipThisRegion ? "<deleted>" :
                                       CurrentRegion->getNameStr());
         dumpPreservedSet(P);
+      }
 
       if (!skipThisRegion) {
         // Manually check that this region is still healthy. This is done
@@ -120,8 +124,8 @@ bool RGPassManager::runOnFunction(Function &F) {
       removeNotPreservedAnalysis(P);
       recordAvailableAnalysis(P);
       removeDeadPasses(P,
-                       skipThisRegion ? "<deleted>" :
-                                      CurrentRegion->getNameStr(),
+                       (!isPassDebuggingExecutionsOrMore() || skipThisRegion) ?
+                       "<deleted>" :  CurrentRegion->getNameStr(),
                        ON_REGION_MSG);
 
       if (skipThisRegion)