From: lucasart <lucas.braesch@gmail.com>
Date: Thu, 3 Jul 2014 10:22:53 +0000 (+0800)
Subject: Use compiler intrinsic instead of assembly for popcnt
X-Git-Url: https://git.sesse.net/?p=stockfish;a=commitdiff_plain;h=85b08ce3adafbb1a70cd371cadb1e136e8879ebf;ds=inline

Use compiler intrinsic instead of assembly for popcnt
This time, do not break compatibility with some AMD machines that have SSE3 and popcnt, but do
not have SSE4.2.

No functional change.
---

diff --git a/src/Makefile b/src/Makefile
index 187e7b31..1e5a1658 100644
--- a/src/Makefile
+++ b/src/Makefile
@@ -285,7 +285,7 @@ endif
 
 ### 3.9 popcnt
 ifeq ($(popcnt),yes)
-	CXXFLAGS += -msse3 -DUSE_POPCNT
+	CXXFLAGS += -msse3 -mpopcnt -DUSE_POPCNT
 endif
 
 ### 3.10 pext
diff --git a/src/bitcount.h b/src/bitcount.h
index f84c51cb..9feed19f 100644
--- a/src/bitcount.h
+++ b/src/bitcount.h
@@ -96,8 +96,7 @@ inline int popcount<CNT_HW_POPCNT>(Bitboard b) {
 
 #else
 
-  __asm__("popcnt %1, %0" : "=r" (b) : "r" (b));
-  return b;
+  return __builtin_popcountll(b);
 
 #endif
 }