From f4140ecc0c78d3d89f4e2459105e3ce3a1ab3ce1 Mon Sep 17 00:00:00 2001 From: Marco Costalba Date: Mon, 10 Aug 2009 12:59:07 +0200 Subject: [PATCH] Avoid Intel compiler optimizes away prefetching Without this hack Intel compiler happily optimizes away the gcc builtin call. Signed-off-by: Marco Costalba --- src/tt.cpp | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/src/tt.cpp b/src/tt.cpp index 770e38b7..0396b287 100644 --- a/src/tt.cpp +++ b/src/tt.cpp @@ -181,7 +181,10 @@ void TranspositionTable::prefetch(const Key posKey) const { #if defined(_MSC_VER) _mm_prefetch((char*)first_entry(posKey), _MM_HINT_T0); #else - __builtin_prefetch((const void*)first_entry(posKey), 0, 3); + // We need to force an asm volatile here because gcc builtin + // is optimized away by Intel compiler. + char* addr = (char*)first_entry(posKey); + asm volatile("prefetcht0 %0" :: "m" (addr)); #endif } -- 2.39.2