From: liuhongt <hongtao.liu@intel.com>
Date: Mon, 26 Jun 2023 01:50:25 +0000 (+0800)
Subject: Make option mvzeroupper independent of optimization level.
X-Git-Tag: releases/gcc-11.5.0~706
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3942da3db0983a51b90b93decb64c6ed166f7b15;p=thirdparty%2Fgcc.git

Make option mvzeroupper independent of optimization level.

pass_insert_vzeroupper is under condition

TARGET_AVX && TARGET_VZEROUPPER
&& flag_expensive_optimizations && !optimize_size

But the document of mvzeroupper doesn't mention the insertion
required -O2 and above, it may confuse users when they explicitly
use -Os -mvzeroupper.

------------
mvzeroupper
Target Mask(VZEROUPPER) Save
Generate vzeroupper instruction before a transfer of control flow out of
the function.
------------

The patch moves flag_expensive_optimizations && !optimize_size to
ix86_option_override_internal. It makes -mvzeroupper independent of
optimization level, but still keeps the behavior of architecture
tuning(emit_vzeroupper) unchanged.

gcc/ChangeLog:

	* config/i386/i386-features.c (pass_insert_vzeroupper:gate):
	Move flag_expensive_optimizations && !optimize_size to ..
	* config/i386/i386-options.c (ix86_option_override_internal):
	.. this, it makes -mvzeroupper independent of optimization
	level, but still keeps the behavior of architecture
	tuning(emit_vzeroupper) unchanged.
	(rest_of_handle_insert_vzeroupper): Remove
	flag_expensive_optimizations && !optimize_size.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/avx-vzeroupper-29.c: New testcase.
---

diff --git a/gcc/config/i386/i386-features.c b/gcc/config/i386/i386-features.c
index 77783a154b68..19033dc3df58 100644
--- a/gcc/config/i386/i386-features.c
+++ b/gcc/config/i386/i386-features.c
@@ -1837,9 +1837,7 @@ ix86_add_reg_usage_to_vzerouppers (void)
 static unsigned int
 rest_of_handle_insert_vzeroupper (void)
 {
-  if (TARGET_VZEROUPPER
-      && flag_expensive_optimizations
-      && !optimize_size)
+  if (TARGET_VZEROUPPER)
     {
       /* vzeroupper instructions are inserted immediately after reload to
 	 account for possible spills from 256bit or 512bit registers.  The pass
@@ -1883,9 +1881,7 @@ public:
   virtual bool gate (function *)
     {
       return TARGET_AVX
-	     && ((TARGET_VZEROUPPER
-		  && flag_expensive_optimizations
-		  && !optimize_size)
+	     && (TARGET_VZEROUPPER
 		 || cfun->machine->has_explicit_vzeroupper);
     }
 
diff --git a/gcc/config/i386/i386-options.c b/gcc/config/i386/i386-options.c
index b74df4d549e4..d47a5433126f 100644
--- a/gcc/config/i386/i386-options.c
+++ b/gcc/config/i386/i386-options.c
@@ -2849,7 +2849,9 @@ ix86_option_override_internal (bool main_args_p,
     sorry ("%<-mcall-ms2sysv-xlogues%> isn%'t currently supported with SEH");
 
   if (!(opts_set->x_target_flags & MASK_VZEROUPPER)
-      && TARGET_EMIT_VZEROUPPER)
+      && TARGET_EMIT_VZEROUPPER
+      && flag_expensive_optimizations
+      && !optimize_size)
     opts->x_target_flags |= MASK_VZEROUPPER;
   if (!(opts_set->x_target_flags & MASK_STV))
     opts->x_target_flags |= MASK_STV;
diff --git a/gcc/testsuite/gcc.target/i386/avx-vzeroupper-29.c b/gcc/testsuite/gcc.target/i386/avx-vzeroupper-29.c
new file mode 100644
index 000000000000..4af637757f76
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/avx-vzeroupper-29.c
@@ -0,0 +1,14 @@
+/* { dg-do compile } */
+/* { dg-options "-O0 -mavx -mtune=generic -mvzeroupper -dp" } */
+
+#include <immintrin.h>
+
+extern __m256 x, y;
+
+void
+foo ()
+{
+  x = y;
+}
+
+/* { dg-final { scan-assembler-times "avx_vzeroupper" 1 } } */