[llvm] 3c775d9 - [InlineCost] Reject a zero entry count

[Kazu Hirata via llvm-commits]

Author: Kazu Hirata
Date: 2021-03-25T21:51:36-07:00
New Revision: 3c775d93a1dda3cec3bb6c7617c4b4ab770f4af0

URL: https://github.com/llvm/llvm-project/commit/3c775d93a1dda3cec3bb6c7617c4b4ab770f4af0
DIFF: https://github.com/llvm/llvm-project/commit/3c775d93a1dda3cec3bb6c7617c4b4ab770f4af0.diff

LOG: [InlineCost] Reject a zero entry count

This patch teaches the cost-benefit-analysis-based inliner to reject a
zero entry count so that we don't trigger a divide-by-zero.

Added: 
    

Modified: 
    llvm/lib/Analysis/InlineCost.cpp

Removed: 
    


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diff  --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
index c02b56797be3..538dfacdaa5b 100644
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -696,7 +696,9 @@ class InlineCostCallAnalyzer final : public CallAnalyzer {
     if (!PSI->isHotCallSite(CandidateCall, CallerBFI))
       return false;
 
-    if (!F.getEntryCount())
+    // Make sure we have a nonzero entry count.
+    auto EntryCount = F.getEntryCount();
+    if (!EntryCount || !EntryCount.getCount())
       return false;
 
     BlockFrequencyInfo *CalleeBFI = &(GetBFI(F));
@@ -765,7 +767,7 @@ class InlineCostCallAnalyzer final : public CallAnalyzer {
 
     // Compute the cycle savings per call.
     auto EntryProfileCount = F.getEntryCount();
-    assert(EntryProfileCount.hasValue());
+    assert(EntryProfileCount.hasValue() && EntryProfileCount.getCount());
     auto EntryCount = EntryProfileCount.getCount();
     CycleSavings += EntryCount / 2;
     CycleSavings = CycleSavings.udiv(EntryCount);