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.

diff --git a/libatomic/ChangeLog b/libatomic/ChangeLog
index 624162db9117b3bd75d61434f1d3dc513ff43e6e..33527a7b4564d6239103e6458fbf9821930eef00 100644 (file)
--- 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 7828162c68b736fe51e99848e288203b8e955e3f..d7b1bbe5ea125a5d300a2c84dda14124aba1e9cd 100644 (file)
--- 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 3426ff8470b0b3fe2d652fc9b43cf344f6aba62c..d66f76fdd0180bce4be2c8dab66bc96f84acd31e 100644 (file)
--- 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 c994491c650dc66ee139a7b696432b73cc67ecbd..31a24ced704a7b0a17f9e3a876cd6cb070416c85 100644 (file)
--- 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 e33d3495028b49539103647793d66eb3c801ba1d..2ca75f190bc9016e5428e4f55c08de547a3cc4e1 100644 (file)
--- 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 623e878b482e0fde7c0da31681fa0ea535a7a436..13be2045b72f8bc8310b29dccaf2cdfac28b5f52 100644 (file)
--- 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.  */