From 4f78f9fbb05145d437540181fda9bcc83d5a53e4 Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu@gmail.com>
Date: Fri, 26 Jul 2024 19:36:21 +0100
Subject: Force LLVM to use CMOV for binary search

Since https://reviews.llvm.org/D118118, LLVM will no longer turn CMOVs
into branches if it comes from a `select` marked with an `unpredictable`
metadata attribute.

This PR introduces `core::intrinsics::select_unpredictable` which emits
such a `select` and uses it in the implementation of `binary_search_by`.
---
 compiler/rustc_codegen_llvm/src/llvm/ffi.rs | 1 +
 1 file changed, 1 insertion(+)

(limited to 'compiler/rustc_codegen_llvm/src/llvm')

diff --git a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
index 3beda28ac1f..1e2b0292d36 100644
--- a/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
+++ b/compiler/rustc_codegen_llvm/src/llvm/ffi.rs
@@ -428,6 +428,7 @@ pub enum MetadataType {
     MD_nontemporal = 9,
     MD_mem_parallel_loop_access = 10,
     MD_nonnull = 11,
+    MD_unpredictable = 15,
     MD_align = 17,
     MD_type = 19,
     MD_vcall_visibility = 28,
-- 
cgit 1.4.1-3-g733a5