commit d59eabb1219bd7c0585e4e86fe9147473c703f33
author Chris Kennelly <ckennelly@google.com> Thu Oct 26 08:43:56 2023 -0700
committer Copybara-Service <copybara-worker@google.com> Thu Oct 26 08:44:46 2023 -0700
tree ba28490ed60d3066d61b64e0ba8fdfefc78ac8ba
parent 4a6ea63d35d28785b87c51536aed00362a94c5f9

Prefer builtin to inline assembly when built with -mprfchw.

PiperOrigin-RevId: 576884571
Change-Id: I7bfe68e5aedd8563f8e6dbdb5d7cc66e9af22567

absl/base/prefetch.h

diff --git a/absl/base/prefetch.h b/absl/base/prefetch.h
index 609e26e..98b3bf9 100644
--- a/absl/base/prefetch.h
+++ b/absl/base/prefetch.h
@@ -157,7 +157,7 @@
   // unless -march=broadwell or newer; this is not generally the default, so we
   // manually emit prefetchw. PREFETCHW is recognized as a no-op on older Intel
   // processors and has been present on AMD processors since the K6-2.
-#if defined(__x86_64__)
+#if defined(__x86_64__) && !defined(__PRFCHW__)
   asm("prefetchw %0" : : "m"(*reinterpret_cast<const char*>(addr)));
 #else
   __builtin_prefetch(addr, 1, 3);