From bbc629ebd6429d43cfd72d9a0e2b5ca8a4083b54 Mon Sep 17 00:00:00 2001
From: Kirill Bobyrev <kbobyrev@google.com>
Date: Wed, 17 Jun 2020 10:44:28 +0200
Subject: [PATCH] [CallPrinter] Fix maxFreq = 0 case

llvm::getHeatColor becomes a problem when maxFreq = 0 -> freq = 0 =>
log2(double(freq)) / log2(maxFreq) -> log2(0.) / log2(0.) which
results in illegal instruction on some architectures.

Problematic revision: https://reviews.llvm.org/D77172
---
 llvm/lib/Analysis/HeatUtils.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/Analysis/HeatUtils.cpp b/llvm/lib/Analysis/HeatUtils.cpp
index 99d39d8bbe9e..15d672ffbf9a 100644
--- a/llvm/lib/Analysis/HeatUtils.cpp
+++ b/llvm/lib/Analysis/HeatUtils.cpp
@@ -62,7 +62,7 @@ uint64_t getMaxFreq(const Function &F, const BlockFrequencyInfo *BFI) {
 std::string getHeatColor(uint64_t freq, uint64_t maxFreq) {
   if (freq > maxFreq)
     freq = maxFreq;
-  double percent = log2(double(freq)) / log2(maxFreq);
+  double percent = (maxFreq > 0) ? log2(double(freq)) / log2(maxFreq) : 0;
   return getHeatColor(percent);
 }