[llvm] [libc][bazel] Re-enable memcpy prefetching on x86. (PR #138945)

[via llvm-commits]

llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-libc

Author: Alexey Samsonov (vonosmas)

<details>
<summary>Changes</summary>

It was re-enabled downstream after further performance analysis, so we can revert c65ed964657c93d51f3e05de9e0609419768a143, effectively re-landing the change.

---
Full diff: https://github.com/llvm/llvm-project/pull/138945.diff


1 Files Affected:

- (modified) utils/bazel/llvm-project-overlay/libc/libc_configure_options.bzl (+1-1) 


``````````diff
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 f65da9e98226b..96d7fa86e9ddf 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

``````````

</details>


https://github.com/llvm/llvm-project/pull/138945