Fix coverage check for full post-dominator basic blocks.
Coverage instrumentation which does not instrument full post-dominators
and full-dominators may skip valid paths, as the reasoning for skipping
blocks may become circular.
This patch fixes that, by only skipping
full post-dominators with multiple predecessors, as such predecessors by
definition can not be full-dominators.
llvm-svn: 303827
diff --git a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
index 4bc0a71..300085e 100644
--- a/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
+++ b/llvm/lib/Transforms/Instrumentation/SanitizerCoverage.cpp
@@ -401,7 +401,10 @@
if (Options.NoPrune || &F.getEntryBlock() == BB)
return true;
- return !(isFullDominator(BB, DT) || isFullPostDominator(BB, PDT));
+ // Do not instrument full dominators, or full post-dominators with multiple
+ // predecessors.
+ return !isFullDominator(BB, DT)
+ && !(isFullPostDominator(BB, PDT) && !BB->getSinglePredecessor());
}
bool SanitizerCoverageModule::runOnFunction(Function &F) {