[glibc/release/2.34/master] x86_64: Fix asm constraints in feraiseexcept (bug 30305)

[glibc/release/2.34/master] x86_64: Fix asm constraints in feraiseexcept (bug 30305)

[Florian Weimer]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=71eb9cc1ffd79e96549dfb16f8e86aaf88a3bac8

commit 71eb9cc1ffd79e96549dfb16f8e86aaf88a3bac8
Author: Florian Weimer <fweimer@redhat.com>
Date:   Mon Apr 3 17:23:11 2023 +0200

    x86_64: Fix asm constraints in feraiseexcept (bug 30305)
    
    The divss instruction clobbers its first argument, and the constraints
    need to reflect that.  Fortunately, with GCC 12, generated code does
    not actually change, so there is no externally visible bug.
    
    Suggested-by: Jakub Jelinek <jakub@redhat.com>
    Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
    (cherry picked from commit 5d1ccdda7b0c625751661d50977f3dfbc73f8eae)

Diff:
---
 NEWS                             | 1 +
 sysdeps/x86_64/fpu/fraiseexcpt.c | 4 ++--
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/NEWS b/NEWS
index 41e0685ca7..545ede4f55 100644
--- a/NEWS
+++ b/NEWS
@@ -140,6 +140,7 @@ The following bugs are resolved with this release:
   [29953] x86: Check minimum/maximum of non_temporal_threshold
   [30053] time: strftime %s returns -1 after 2038 on 32 bits systems
   [30151] gshadow: Matching sgetsgent, sgetsgent_r ERANGE handling
+  [30305] x86_64: Fix asm constraints in feraiseexcept
 
 \f
 Version 2.34
diff --git a/sysdeps/x86_64/fpu/fraiseexcpt.c b/sysdeps/x86_64/fpu/fraiseexcpt.c
index 44a1d93b34..a301b657c4 100644
--- a/sysdeps/x86_64/fpu/fraiseexcpt.c
+++ b/sysdeps/x86_64/fpu/fraiseexcpt.c
@@ -33,7 +33,7 @@ __feraiseexcept (int excepts)
       /* One example of an invalid operation is 0.0 / 0.0.  */
       float f = 0.0;
 
-      __asm__ __volatile__ ("divss %0, %0 " : : "x" (f));
+      __asm__ __volatile__ ("divss %0, %0 " : "+x" (f));
       (void) &f;
     }
 
@@ -43,7 +43,7 @@ __feraiseexcept (int excepts)
       float f = 1.0;
       float g = 0.0;
 
-      __asm__ __volatile__ ("divss %1, %0" : : "x" (f), "x" (g));
+      __asm__ __volatile__ ("divss %1, %0" : "+x" (f) : "x" (g));
       (void) &f;
     }