From df73e5842f25aea3bab81c328ed77f16ed261b33 Mon Sep 17 00:00:00 2001
From: Uros Bizjak <ubizjak@gmail.com>
Date: Sun, 19 Apr 2020 14:23:47 +0200
Subject: [PATCH] i386: Remove unneeded assignments when triggering SSE
exceptions
According to "Intel 64 and IA32 Arch SDM, Vol. 3:
"Because SIMD floating-point exceptions are precise and occur immediately,
the situation does not arise where an x87 FPU instruction, a WAIT/FWAIT
instruction, or another SSE/SSE2/SSE3 instruction will catch a pending
unmasked SIMD floating-point exception."
Remove unneeded assignments to volatile memory.
libgcc/ChangeLog:
* config/i386/sfp-exceptions.c (__sfp_handle_exceptions) [__SSE_MATH__]:
Remove unneeded assignments to volatile memory.
libatomic/ChangeLog:
* config/x86/fenv.c (__atomic_feraiseexcept) [__SSE_MATH__]:
Remove unneeded assignments to volatile memory.
libgfortran/ChangeLog:
* config/fpu-387.h (local_feraiseexcept) [__SSE_MATH__]:
Remove unneeded assignments to volatile memory.
---
libatomic/ChangeLog | 5 +++++
libatomic/config/x86/fenv.c | 6 ------
libgcc/ChangeLog | 5 +++++
libgcc/config/i386/sfp-exceptions.c | 6 ------
libgfortran/ChangeLog | 5 +++++
libgfortran/config/fpu-387.h | 6 ------
6 files changed, 15 insertions(+), 18 deletions(-)
diff --git a/libatomic/ChangeLog b/libatomic/ChangeLog
index 624162db9117..33527a7b4564 100644
--- a/libatomic/ChangeLog
+++ b/libatomic/ChangeLog
@@ -1,3 +1,8 @@
+2020-04-19 Uroš Bizjak <ubizjak@gmail.com>
+
+ * config/x86/fenv.c (__atomic_feraiseexcept) [__SSE_MATH__]:
+ Remove unneeded assignments to volatile memory.
+
2020-04-06 Maciej W. Rozycki <macro@wdc.com>
* configure.ac: Add testsuite/libatomic-site-extra.exp to output
diff --git a/libatomic/config/x86/fenv.c b/libatomic/config/x86/fenv.c
index 7828162c68b7..d7b1bbe5ea12 100644
--- a/libatomic/config/x86/fenv.c
+++ b/libatomic/config/x86/fenv.c
@@ -57,9 +57,7 @@ __atomic_feraiseexcept (int excepts)
{
float f = 0.0f;
#ifdef __SSE_MATH__
- volatile float r __attribute__ ((unused));
asm volatile ("%vdivss\t{%0, %d0|%d0, %0}" : "+x" (f));
- r = f; /* Needed to trigger exception. */
#else
asm volatile ("fdiv\t{%y0, %0|%0, %y0}" : "+t" (f));
/* No need for fwait, exception is triggered by emitted fstp. */
@@ -77,9 +75,7 @@ __atomic_feraiseexcept (int excepts)
{
float f = 1.0f, g = 0.0f;
#ifdef __SSE_MATH__
- volatile float r __attribute__ ((unused));
asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
- r = f; /* Needed to trigger exception. */
#else
asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
/* No need for fwait, exception is triggered by emitted fstp. */
@@ -105,9 +101,7 @@ __atomic_feraiseexcept (int excepts)
{
float f = 1.0f, g = 3.0f;
#ifdef __SSE_MATH__
- volatile float r __attribute__ ((unused));
asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
- r = f; /* Needed to trigger exception. */
#else
asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
/* No need for fwait, exception is triggered by emitted fstp. */
diff --git a/libgcc/ChangeLog b/libgcc/ChangeLog
index 3426ff8470b0..d66f76fdd018 100644
--- a/libgcc/ChangeLog
+++ b/libgcc/ChangeLog
@@ -1,3 +1,8 @@
+2020-04-19 Uroš Bizjak <ubizjak@gmail.com>
+
+ * config/i386/sfp-exceptions.c (__sfp_handle_exceptions) [__SSE_MATH__]:
+ Remove unneeded assignments to volatile memory.
+
2020-04-15 Jakub Jelinek <jakub@redhat.com>
PR target/93053
diff --git a/libgcc/config/i386/sfp-exceptions.c b/libgcc/config/i386/sfp-exceptions.c
index c994491c650d..31a24ced704a 100644
--- a/libgcc/config/i386/sfp-exceptions.c
+++ b/libgcc/config/i386/sfp-exceptions.c
@@ -48,9 +48,7 @@ __sfp_handle_exceptions (int _fex)
{
float f = 0.0f;
#ifdef __SSE_MATH__
- volatile float r __attribute__ ((unused));
asm volatile ("%vdivss\t{%0, %d0|%d0, %0}" : "+x" (f));
- r = f; /* Needed to trigger exception. */
#else
asm volatile ("fdiv\t{%y0, %0|%0, %y0}" : "+t" (f));
/* No need for fwait, exception is triggered by emitted fstp. */
@@ -68,9 +66,7 @@ __sfp_handle_exceptions (int _fex)
{
float f = 1.0f, g = 0.0f;
#ifdef __SSE_MATH__
- volatile float r __attribute__ ((unused));
asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
- r = f; /* Needed to trigger exception. */
#else
asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
/* No need for fwait, exception is triggered by emitted fstp. */
@@ -96,9 +92,7 @@ __sfp_handle_exceptions (int _fex)
{
float f = 1.0f, g = 3.0f;
#ifdef __SSE_MATH__
- volatile float r __attribute__ ((unused));
asm volatile ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
- r = f; /* Needed to trigger exception. */
#else
asm volatile ("fdivs\t%1" : "+t" (f) : "m" (g));
/* No need for fwait, exception is triggered by emitted fstp. */
diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index e33d3495028b..2ca75f190bc9 100644
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,8 @@
+2020-04-19 Uroš Bizjak <ubizjak@gmail.com>
+
+ * config/fpu-387.h (local_feraiseexcept) [__SSE_MATH__]:
+ Remove unneeded assignments to volatile memory.
+
2020-04-01 Fritz Reese <foreese@gcc.gnu.org>
Steven G. Kargl <kargl@gcc.gnu.org>
diff --git a/libgfortran/config/fpu-387.h b/libgfortran/config/fpu-387.h
index 623e878b482e..13be2045b72f 100644
--- a/libgfortran/config/fpu-387.h
+++ b/libgfortran/config/fpu-387.h
@@ -103,9 +103,7 @@ local_feraiseexcept (int excepts)
{
float f = 0.0f;
#ifdef __SSE_MATH__
- volatile float r __attribute__ ((unused));
__asm__ __volatile__ ("%vdivss\t{%0, %d0|%d0, %0}" : "+x" (f));
- r = f; /* Needed to trigger exception. */
#else
__asm__ __volatile__ ("fdiv\t{%y0, %0|%0, %y0}" : "+t" (f));
/* No need for fwait, exception is triggered by emitted fstp. */
@@ -123,9 +121,7 @@ local_feraiseexcept (int excepts)
{
float f = 1.0f, g = 0.0f;
#ifdef __SSE_MATH__
- volatile float r __attribute__ ((unused));
__asm__ __volatile__ ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
- r = f; /* Needed to trigger exception. */
#else
__asm__ __volatile__ ("fdivs\t%1" : "+t" (f) : "m" (g));
/* No need for fwait, exception is triggered by emitted fstp. */
@@ -151,9 +147,7 @@ local_feraiseexcept (int excepts)
{
float f = 1.0f, g = 3.0f;
#ifdef __SSE_MATH__
- volatile float r __attribute__ ((unused));
__asm__ __volatile__ ("%vdivss\t{%1, %d0|%d0, %1}" : "+x" (f) : "xm" (g));
- r = f; /* Needed to trigger exception. */
#else
__asm__ __volatile__ ("fdivs\t%1" : "+t" (f) : "m" (g));
/* No need for fwait, exception is triggered by emitted fstp. */
--
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