Check for an empty error log.
Fixes #19976.
The error log does not contain an error, in case we reject a candidate
without generating a diagnostic message by using invalid<>(...). This is
the case for the top-level region of a function.
The patch comes without a test-case because adding a useful one requires
additional code just for triggering it. Before the patch it would only trigger,
if we try to print the CFG with Scop error annotations.
llvm-svn: 210753
diff --git a/polly/lib/Analysis/ScopDetection.cpp b/polly/lib/Analysis/ScopDetection.cpp
index 8a9226e..f1fafaa 100644
--- a/polly/lib/Analysis/ScopDetection.cpp
+++ b/polly/lib/Analysis/ScopDetection.cpp
@@ -219,7 +219,14 @@
// Get the first error we found. Even in keep-going mode, this is the first
// reason that caused the candidate to be rejected.
RejectLog Errors = RejectLogs.at(R);
- return (*Errors.begin())->getMessage();
+
+ // This can happen when we marked a region invalid, but didn't track
+ // an error for it.
+ if (Errors.size() == 0)
+ return "";
+
+ RejectReasonPtr RR = *Errors.begin();
+ return RR->getMessage();
}
bool ScopDetection::isValidCFG(BasicBlock &BB,