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From: Florian Weimer <fweimer@redhat.com>
To: libc-alpha@sourceware.org
Subject: [PATCH] x86_64: Fix asm constraints in feraiseexcept (bug 30305)
Date: Mon, 03 Apr 2023 17:43:16 +0200	[thread overview]
Message-ID: <87bkk50y5n.fsf@oldenburg.str.redhat.com> (raw)

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.

Tested on x86_64-linux-gnu.

Suggested-by: Jakub Jelinek <jakub@redhat.com>

---
 sysdeps/x86_64/fpu/fraiseexcpt.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sysdeps/x86_64/fpu/fraiseexcpt.c b/sysdeps/x86_64/fpu/fraiseexcpt.c
index 924eed96a9..e7430a4158 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;
     }
 

base-commit: ac2a14343e81098c196cef5d67b52e440c05c230


             reply	other threads:[~2023-04-03 15:43 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-03 15:43 Florian Weimer [this message]
2023-04-03 15:55 ` Noah Goldstein

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