From 8039d773354360ed8ff2f25c63843fc637eacc67 Mon Sep 17 00:00:00 2001
From: Hongyu Wang <hongyu.wang@intel.com>
Date: Sun, 25 Jun 2023 09:50:21 +0800
Subject: [PATCH 04/28] i386: Sync tune_string with arch_string for target
 attribute

arch=*

For function with target attribute arch=*, current logic will set its
tune to -mtune from command line so all target_clones will get same
tuning flags which would affect the performance for each clone. Override
tune with arch if tune was not explicitly specified to get proper tuning
flags for target_clones.

gcc/ChangeLog:

	* config/i386/i386-options.cc (ix86_valid_target_attribute_tree):
	Override tune_string with arch_string if tune_string is not
	explicitly specified.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/mvc17.c: New test.

(cherry picked from commit 2916278d14e9ac28c361c396a67256acbebda6e8)
---
 gcc/config/i386/i386-options.cc       |  6 +++++-
 gcc/testsuite/gcc.target/i386/mvc17.c | 11 +++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/mvc17.c

diff --git a/gcc/config/i386/i386-options.cc b/gcc/config/i386/i386-options.cc
index 74e969b68..fb2ed942f 100644
--- a/gcc/config/i386/i386-options.cc
+++ b/gcc/config/i386/i386-options.cc
@@ -1378,7 +1378,11 @@ ix86_valid_target_attribute_tree (tree fndecl, tree args,
       if (option_strings[IX86_FUNCTION_SPECIFIC_TUNE])
 	opts->x_ix86_tune_string
 	  = ggc_strdup (option_strings[IX86_FUNCTION_SPECIFIC_TUNE]);
-      else if (orig_tune_defaulted)
+      /* If we have explicit arch string and no tune string specified, set
+	 tune_string to NULL and later it will be overriden by arch_string
+	 so target clones can get proper optimization.  */
+      else if (option_strings[IX86_FUNCTION_SPECIFIC_ARCH]
+	       || orig_tune_defaulted)
 	opts->x_ix86_tune_string = NULL;
 
       /* If fpmath= is not set, and we now have sse2 on 32-bit, use it.  */
diff --git a/gcc/testsuite/gcc.target/i386/mvc17.c b/gcc/testsuite/gcc.target/i386/mvc17.c
new file mode 100644
index 000000000..8b83c1aec
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/mvc17.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-require-ifunc "" } */
+/* { dg-options "-O2 -march=x86-64" } */
+/* { dg-final { scan-assembler-times "rep mov" 1 } } */
+
+__attribute__((target_clones("default","arch=icelake-server")))
+void
+foo (char *a, char *b, int size)
+{
+  __builtin_memcpy (a, b, size & 0x7F);
+}
-- 
2.31.1