From: Reid Kleckner <reid@kleckner.net>
Date: Tue, 6 Aug 2013 19:45:27 +0000 (+0000)
Subject: Use gnu style builtins in MathExtras.h with clang on Windows
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=ae8e3cfbca31cddac5a891b1d5606399dd4fefe0;p=oota-llvm.git

Use gnu style builtins in MathExtras.h with clang on Windows

Clang does not provide BitScan* intrinsic implementations yet.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187813 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/llvm/Support/MathExtras.h b/include/llvm/Support/MathExtras.h
index 7742e32737a..00c6ad70d43 100644
--- a/include/llvm/Support/MathExtras.h
+++ b/include/llvm/Support/MathExtras.h
@@ -80,7 +80,7 @@ inline std::size_t countTrailingZeros<uint32_t>(uint32_t Val, ZeroBehavior ZB) {
   if (ZB != ZB_Undefined && Val == 0)
     return 32;
 
-#if __GNUC__ >= 4
+#if __has_builtin(__builtin_ctz) || __GNUC_PREREQ(4, 0)
   return __builtin_ctz(Val);
 #elif _MSC_VER
   unsigned long Index;
@@ -95,7 +95,7 @@ inline std::size_t countTrailingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) {
   if (ZB != ZB_Undefined && Val == 0)
     return 64;
 
-#if __GNUC__ >= 4
+#if __has_builtin(__builtin_ctzll) || __GNUC_PREREQ(4, 0)
   return __builtin_ctzll(Val);
 #elif _MSC_VER
   unsigned long Index;
@@ -146,7 +146,7 @@ inline std::size_t countLeadingZeros<uint32_t>(uint32_t Val, ZeroBehavior ZB) {
   if (ZB != ZB_Undefined && Val == 0)
     return 32;
 
-#if __GNUC__ >= 4
+#if __has_builtin(__builtin_clz) || __GNUC_PREREQ(4, 0)
   return __builtin_clz(Val);
 #elif _MSC_VER
   unsigned long Index;
@@ -161,7 +161,7 @@ inline std::size_t countLeadingZeros<uint64_t>(uint64_t Val, ZeroBehavior ZB) {
   if (ZB != ZB_Undefined && Val == 0)
     return 64;
 
-#if __GNUC__ >= 4
+#if __has_builtin(__builtin_clzll) || __GNUC_PREREQ(4, 0)
   return __builtin_clzll(Val);
 #elif _MSC_VER
   unsigned long Index;