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 329f4c36a9adcbe69dcbe668c090de5c5feb70d8..a5e0c21ec1a6398c50a636c19bb1dd7f8f54ed85 100644 (file)
--- a/gcc/config/i386/i386-features.c
+++ b/gcc/config/i386/i386-features.c
@@ -1825,9 +1825,7 @@ 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
@@ -1871,9 +1869,7 @@ 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 7bb644b67b4a67a48299b1ee72b8f878313808db..3510ad5f5d71077cd21055fd02238836a6e8d95b 100644 (file)
--- a/gcc/config/i386/i386-options.c
+++ b/gcc/config/i386/i386-options.c
@@ -2715,7 +2715,9 @@ 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 (file)
index 0000000..4af6377
--- /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 } } */