X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FSupport%2FBlockFrequency.cpp;h=5e45e46cf9743d73bb5f44f221dba936aa7f8571;hb=e2ff00e117ba9b758b298e671f65c0b002f8a52d;hp=08fa620eb8839ce93e258a40642f5dc18c0b5d44;hpb=d7648ff20f8bbc8217a26576ca96addc55e003de;p=oota-llvm.git

diff --git a/lib/Support/BlockFrequency.cpp b/lib/Support/BlockFrequency.cpp
index 08fa620eb88..5e45e46cf97 100644
--- a/lib/Support/BlockFrequency.cpp
+++ b/lib/Support/BlockFrequency.cpp
@@ -18,10 +18,8 @@
 
 using namespace llvm;
 
-namespace {
-
-/// mult96bit - Multiply FREQ by N and store result in W array.
-void mult96bit(uint64_t freq, uint32_t N, uint64_t W[2]) {
+/// Multiply FREQ by N and store result in W array.
+static void mult96bit(uint64_t freq, uint32_t N, uint64_t W[2]) {
   uint64_t u0 = freq & UINT32_MAX;
   uint64_t u1 = freq >> 32;
 
@@ -42,16 +40,18 @@ void mult96bit(uint64_t freq, uint32_t N, uint64_t W[2]) {
 }
 
 
-/// div96bit - Divide 96-bit value stored in W array by D.
+/// Divide 96-bit value stored in W array by D.
 /// Return 64-bit quotient, saturated to UINT64_MAX on overflow.
-uint64_t div96bit(uint64_t W[2], uint32_t D) {
+static uint64_t div96bit(uint64_t W[2], uint32_t D) {
   uint64_t y = W[0];
   uint64_t x = W[1];
-  int i;
+  unsigned i;
+
+  assert(x != 0 && "This is really a 64-bit division");
 
   // This long division algorithm automatically saturates on overflow.
-  for (i = 1; i <= 64 && x; ++i) {
-    uint32_t t = (int)x >> 31;
+  for (i = 0; i < 64 && x; ++i) {
+    uint32_t t = -((x >> 31) & 1); // Splat bit 31 to bits 0-31.
     x = (x << 1) | (y >> 63);
     y = y << 1;
     if ((x | t) >= D) {
@@ -60,10 +60,9 @@ uint64_t div96bit(uint64_t W[2], uint32_t D) {
     }
   }
 
-  return y << (64 - i + 1);
+  return y << (64 - i);
 }
 
-}
 
 void BlockFrequency::scale(uint32_t N, uint32_t D) {
   assert(D != 0 && "Division by zero");
@@ -74,7 +73,7 @@ void BlockFrequency::scale(uint32_t N, uint32_t D) {
   uint64_t MulRes = (MulHi << 32) + MulLo;
 
   // If the product fits in 64 bits, just use built-in division.
-  if (MulHi <= UINT32_MAX && MulRes <= MulLo) {
+  if (MulHi <= UINT32_MAX && MulRes >= MulLo) {
     Frequency = MulRes / D;
     return;
   }