From 9b8a6a3b2b28dbe84f9e25d1b5c4832da372a96f Mon Sep 17 00:00:00 2001
From: Jakub Staszak <jstaszak@apple.com>
Date: Wed, 27 Jul 2011 16:00:40 +0000
Subject: Optimize 96-bit division a little bit.

llvm-svn: 136222
---
 llvm/lib/Support/BlockFrequency.cpp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

(limited to 'llvm/lib/Support/BlockFrequency.cpp')

diff --git a/llvm/lib/Support/BlockFrequency.cpp b/llvm/lib/Support/BlockFrequency.cpp
index 0bc78408104..a63bf83f203 100644
--- a/llvm/lib/Support/BlockFrequency.cpp
+++ b/llvm/lib/Support/BlockFrequency.cpp
@@ -46,8 +46,9 @@ void mult96bit(uint64_t freq, uint32_t N, uint64_t W[2]) {
 uint64_t div96bit(uint64_t W[2], uint32_t D) {
   uint64_t y = W[0];
   uint64_t x = W[1];
+  int i;
 
-  for (int i = 1; i <= 64; ++i) {
+  for (i = 1; i <= 64 && x; ++i) {
     uint32_t t = (int)x >> 31;
     x = (x << 1) | (y >> 63);
     y = y << 1;
@@ -57,7 +58,7 @@ uint64_t div96bit(uint64_t W[2], uint32_t D) {
     }
   }
 
-  return y;
+  return y << (64 - i + 1);
 }
 
 }
-- 
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