[SampleFDO] Extend profile-sample-accurate option to cover isFunctionColdInCallGraph

For SampleFDO, when a callsite doesn't appear in the profile, it will not be marked as cold callsite unless the option -profile-sample-accurate is specified.

But profile-sample-accurate doesn't cover function isFunctionColdInCallGraph which is used to decide whether a function should be put into text.unlikely section, so even if the user knows the profile is accurate and specifies profile-sample-accurate, those functions not appearing in the sample profile are still not be put into text.unlikely section right now.

The patch fixes that.

Differential Revision: https://reviews.llvm.org/D55567

llvm-svn: 348940

1 files changed, 8 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/ProfileSummaryInfo.cpp b/llvm/lib/Analysis/ProfileSummaryInfo.cpp
index bd8459ddb82..4326e53b43b 100644
--- a/llvm/lib/Analysis/ProfileSummaryInfo.cpp
+++ b/llvm/lib/Analysis/ProfileSummaryInfo.cpp
@@ -261,7 +261,14 @@ bool ProfileSummaryInfo::isHotBlock(const BasicBlock *BB, BlockFrequencyInfo *BF
 bool ProfileSummaryInfo::isColdBlock(const BasicBlock *BB,
                                   BlockFrequencyInfo *BFI) {
   auto Count = BFI->getBlockProfileCount(BB);
-  return Count && isColdCount(*Count);
+  if (Count)
+    return isColdCount(*Count);
+  if (!hasSampleProfile())
+    return false;
+
+  const Function *F = BB->getParent();
+  return ProfileSampleAccurate ||
+         (F && F->hasFnAttribute("profile-sample-accurate"));
 }
 
 bool ProfileSummaryInfo::isHotCallSite(const CallSite &CS,