From 67a2dee8c59a7aa4d97e5c0cac307215e461dd26 Mon Sep 17 00:00:00 2001
From: Yi Kong <yikong@google.com>
Date: Fri, 1 Sep 2023 21:52:36 +0900
Subject: [PATCH] Enable MLGO for register allocation

This enables Machine Learning Guided Optimizations (MLGO) for register
allocation. App launch performance on oriole-userdebug is improved by
0.53%, and binary size is very slightly reduced (e.g. 64 bytes for
libart.so).

https://dashboards.corp.google.com/_0e1b06dd_a79e_4433_b625_b62e5cac004b?p=BootImageProfileId:36265

Test: presubmit
Bug: 229056536
Change-Id: I0e5d40bb90a1555a1343f114ebffffca281f20b2
---
 cc/config/global.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/cc/config/global.go b/cc/config/global.go
index 472ce4095..3ee3fa2bb 100644
--- a/cc/config/global.go
+++ b/cc/config/global.go
@@ -140,6 +140,9 @@ var (
 		"-Werror=format-security",
 		"-nostdlibinc",
 
+		// Enable MLGO for register allocation.
+		"-mllvm -regalloc-enable-advisor=release",
+
 		// Emit additional debug info for AutoFDO
 		"-fdebug-info-for-profiling",
 	}
@@ -167,6 +170,8 @@ var (
 		"-Wl,--exclude-libs,libgcc_stripped.a",
 		"-Wl,--exclude-libs,libunwind_llvm.a",
 		"-Wl,--exclude-libs,libunwind.a",
+		// Enable MLGO for register allocation.
+		"-Wl,-mllvm,-regalloc-enable-advisor=release",
 	}
 
 	deviceGlobalLldflags = append(deviceGlobalLdflags, commonGlobalLldflags...)