[llvm] Revert "[reland][libc][bazel] Enable software prefetching for memcpy" (PR #127189)

[Guillaume Chatelet via llvm-commits]

https://github.com/gchatelet created https://github.com/llvm/llvm-project/pull/127189

Reverts llvm/llvm-project#113886

We suspect this has caused internal performance regressions, reverting while root causing it more thoroughly.

>From c985e5c9f3f819c7b6c65fbd34131afff1788474 Mon Sep 17 00:00:00 2001
From: Guillaume Chatelet <chatelet.guillaume at gmail.com>
Date: Fri, 14 Feb 2025 11:12:03 +0100
Subject: [PATCH] Revert "[reland][libc][bazel] Enable software prefetching for
 memcpy (#113886)"

This reverts commit b1ede8fcb45d91092f5afe6c88d7a548f14ed848.
---
 .../bazel/llvm-project-overlay/libc/libc_configure_options.bzl  | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/utils/bazel/llvm-project-overlay/libc/libc_configure_options.bzl b/utils/bazel/llvm-project-overlay/libc/libc_configure_options.bzl
index 96d7fa86e9ddf..f65da9e98226b 100644
--- a/utils/bazel/llvm-project-overlay/libc/libc_configure_options.bzl
+++ b/utils/bazel/llvm-project-overlay/libc/libc_configure_options.bzl
@@ -24,7 +24,7 @@ LIBC_CONFIGURE_OPTIONS = [
     # Documentation in libc/src/string/memory_utils/...
     # "LIBC_COPT_MEMCPY_USE_EMBEDDED_TINY",
     # "LIBC_COPT_MEMCPY_X86_USE_REPMOVSB_FROM_SIZE",
-    "LIBC_COPT_MEMCPY_X86_USE_SOFTWARE_PREFETCHING",
+    # "LIBC_COPT_MEMCPY_X86_USE_SOFTWARE_PREFETCHING",
     "LIBC_COPT_MEMSET_X86_USE_SOFTWARE_PREFETCHING",
 
     # Documentation in libc/docs/dev/printf_behavior.rst