ScopDetection: Support keep-going

Support a 'keep-going' mode for the ScopDetection. In this mode, we just keep
on detecting, even if we encounter an error.

This is useful for diagnosing SCoP candidates. Sometimes you want all the
errors. Invalid SCoPs will still be refused in the end, we just refuse to
abort on the first error.

llvm-svn: 209574

2 files changed, 20 insertions, 5 deletions

diff --git a/polly/include/polly/ScopDetectionDiagnostic.h b/polly/include/polly/ScopDetectionDiagnostic.h
index 44b39b87e10..452e25da230 100644
--- a/polly/include/polly/ScopDetectionDiagnostic.h
+++ b/polly/include/polly/ScopDetectionDiagnostic.h
@@ -73,6 +73,7 @@ public:
 
   iterator begin() { return ErrorReports.begin(); }
   iterator end() { return ErrorReports.end(); }
+  size_t size() { return ErrorReports.size(); }
 
   const Region *region() const { return R; }
   void report(RejectReasonPtr Reject) { ErrorReports.push_back(Reject); }
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index 47803530b07..c45524c3754 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -117,6 +117,11 @@ TrackFailures("polly-detect-track-failures",
               cl::location(PollyTrackFailures), cl::Hidden, cl::ZeroOrMore,
               cl::init(false), cl::cat(PollyCategory));
 
+static cl::opt<bool> KeepGoing("polly-detect-keep-going",
+                               cl::desc("Do not fail on the first error."),
+                               cl::Hidden, cl::ZeroOrMore, cl::init(false),
+                               cl::cat(PollyCategory));
+
 static cl::opt<bool, true>
 PollyDelinearizeX("polly-delinearize",
                   cl::desc("Delinearize array access functions"),
@@ -589,7 +594,10 @@ void ScopDetection::findScops(Region &R) {
   if (!DetectRegionsWithoutLoops && regionWithoutLoops(R, LI))
     return;
 
-  if (isValidRegion(R)) {
+  bool IsValidRegion = isValidRegion(R);
+  bool HasErrors = RejectLogs.count(&R) > 0;
+
+  if (IsValidRegion && !HasErrors) {
     ++ValidRegion;
     ValidRegions.insert(&R);
     return;
@@ -598,6 +606,10 @@ void ScopDetection::findScops(Region &R) {
   for (auto &SubRegion : R)
     findScops(*SubRegion);
 
+  // Do not expand when we had errors. Bad things may happen.
+  if (IsValidRegion && HasErrors)
+    return;
+
   // Try to expand regions.
   //
   // As the region tree normally only contains canonical regions, non canonical
@@ -635,17 +647,17 @@ bool ScopDetection::allBlocksValid(DetectionContext &Context) const {
 
   for (const BasicBlock *BB : R.blocks()) {
     Loop *L = LI->getLoopFor(BB);
-    if (L && L->getHeader() == BB && !isValidLoop(L, Context))
+    if (L && L->getHeader() == BB && (!isValidLoop(L, Context) && !KeepGoing))
       return false;
   }
 
   for (BasicBlock *BB : R.blocks())
-    if (!isValidCFG(*BB, Context))
+    if (!isValidCFG(*BB, Context) && !KeepGoing)
       return false;
 
   for (BasicBlock *BB : R.blocks())
     for (BasicBlock::iterator I = BB->begin(), E = --BB->end(); I != E; ++I)
-      if (!isValidInstruction(*I, Context))
+      if (!isValidInstruction(*I, Context) && !KeepGoing)
         return false;
 
   if (!hasAffineMemoryAccesses(Context))
@@ -671,7 +683,9 @@ bool ScopDetection::isValidRegion(Region &R) const {
   DetectionContext Context(R, *AA, false /*verifying*/);
 
   bool RegionIsValid = isValidRegion(Context);
-  if (PollyTrackFailures && !RegionIsValid) {
+  bool HasErrors = !RegionIsValid || Context.Log.size() > 0;
+
+  if (PollyTrackFailures && HasErrors) {
     // std::map::insert does not replace.
     std::pair<reject_iterator, bool> InsertedValue =
         RejectLogs.insert(std::make_pair(&R, Context.Log));