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From: Adhemerval Zanella <azanella@sourceware.org>
To: glibc-cvs@sourceware.org
Subject: [glibc/azanella/clang] i386: sfp-machine.h: Do no use asm input cast for clang
Date: Wed,  7 Feb 2024 14:07:45 +0000 (GMT)	[thread overview]
Message-ID: <20240207140745.6DE783858408@sourceware.org> (raw)

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=4b26cd2ef61f90ed0ee1b73a2614e7a7d5bda04c

commit 4b26cd2ef61f90ed0ee1b73a2614e7a7d5bda04c
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Tue Jul 26 08:45:41 2022 -0300

    i386: sfp-machine.h: Do no use asm input cast for clang
    
    clang by default rejects the input casts with:
    
      error: invalid use of a cast in a inline asm context requiring an
      lvalue: remove the cast or build with -fheinous-gnu-extensions
    
    And even with -fheinous-gnu-extensions clang still throws an warning
    and also states that this option might be removed in the future.
    For gcc the cast are still useful [1] as type-checking.
    
    [1] https://gcc.gnu.org/pipermail/gcc-patches/2021-October/581722.html

Diff:
---
 sysdeps/x86/fpu/sfp-machine.h | 44 +++++++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 18 deletions(-)

diff --git a/sysdeps/x86/fpu/sfp-machine.h b/sysdeps/x86/fpu/sfp-machine.h
index 89a73642b1..dd23c797bd 100644
--- a/sysdeps/x86/fpu/sfp-machine.h
+++ b/sysdeps/x86/fpu/sfp-machine.h
@@ -64,15 +64,23 @@ typedef unsigned int UTItype __attribute__ ((mode (TI)));
 # define _FP_WS_TYPE		signed int
 # define _FP_I_TYPE		int
 
+/* clang does not support output constraint as lvalue, while gcc uses it as a
+   simple type check.  */
+# ifdef __clang__
+#  define __asm_output_check_type(__type, __arg) (__arg)
+# else
+#  define __asm_output_check_type(__type, __arg) ((__type)(__arg))
+# endif
+
 # define __FP_FRAC_ADD_4(r3,r2,r1,r0,x3,x2,x1,x0,y3,y2,y1,y0)	\
   __asm__ ("add{l} {%11,%3|%3,%11}\n\t"				\
 	   "adc{l} {%9,%2|%2,%9}\n\t"				\
 	   "adc{l} {%7,%1|%1,%7}\n\t"				\
 	   "adc{l} {%5,%0|%0,%5}"				\
-	   : "=r" ((USItype) (r3)),				\
-	     "=&r" ((USItype) (r2)),				\
-	     "=&r" ((USItype) (r1)),				\
-	     "=&r" ((USItype) (r0))				\
+	   : "=r" __asm_output_check_type (USItype, r3),	\
+	     "=&r" __asm_output_check_type (USItype, r2),	\
+	     "=&r" __asm_output_check_type (USItype, r1),	\
+	     "=&r" __asm_output_check_type (USItype, r0)	\
 	   : "%0" ((USItype) (x3)),				\
 	     "g" ((USItype) (y3)),				\
 	     "%1" ((USItype) (x2)),				\
@@ -85,9 +93,9 @@ typedef unsigned int UTItype __attribute__ ((mode (TI)));
   __asm__ ("add{l} {%8,%2|%2,%8}\n\t"				\
 	   "adc{l} {%6,%1|%1,%6}\n\t"				\
 	   "adc{l} {%4,%0|%0,%4}"				\
-	   : "=r" ((USItype) (r2)),				\
-	     "=&r" ((USItype) (r1)),				\
-	     "=&r" ((USItype) (r0))				\
+	   : "=r" __asm_output_check_type (USItype, r2),	\
+	     "=&r" __asm_output_check_type (USItype, r1),	\
+	     "=&r" __asm_output_check_type (USItype, r0)	\
 	   : "%0" ((USItype) (x2)),				\
 	     "g" ((USItype) (y2)),				\
 	     "%1" ((USItype) (x1)),				\
@@ -99,10 +107,10 @@ typedef unsigned int UTItype __attribute__ ((mode (TI)));
 	   "sbb{l} {%9,%2|%2,%9}\n\t"				\
 	   "sbb{l} {%7,%1|%1,%7}\n\t"				\
 	   "sbb{l} {%5,%0|%0,%5}"				\
-	   : "=r" ((USItype) (r3)),				\
-	     "=&r" ((USItype) (r2)),				\
-	     "=&r" ((USItype) (r1)),				\
-	     "=&r" ((USItype) (r0))				\
+	   : "=r" __asm_output_check_type (USItype, r3),	\
+	     "=&r" __asm_output_check_type (USItype, r2),	\
+	     "=&r" __asm_output_check_type (USItype, r1),	\
+	     "=&r" __asm_output_check_type (USItype, r0)	\
 	   : "0" ((USItype) (x3)),				\
 	     "g" ((USItype) (y3)),				\
 	     "1" ((USItype) (x2)),				\
@@ -115,9 +123,9 @@ typedef unsigned int UTItype __attribute__ ((mode (TI)));
   __asm__ ("sub{l} {%8,%2|%2,%8}\n\t"				\
 	   "sbb{l} {%6,%1|%1,%6}\n\t"				\
 	   "sbb{l} {%4,%0|%0,%4}"				\
-	   : "=r" ((USItype) (r2)),				\
-	     "=&r" ((USItype) (r1)),				\
-	     "=&r" ((USItype) (r0))				\
+	   : "=r" __asm_output_check_type (USItype, r2),	\
+	     "=&r" __asm_output_check_type (USItype, r1),	\
+	     "=&r" __asm_output_check_type (USItype, r0)	\
 	   : "0" ((USItype) (x2)),				\
 	     "g" ((USItype) (y2)),				\
 	     "1" ((USItype) (x1)),				\
@@ -129,10 +137,10 @@ typedef unsigned int UTItype __attribute__ ((mode (TI)));
 	   "adc{l} {$0,%2|%2,0}\n\t"				\
 	   "adc{l} {$0,%1|%1,0}\n\t"				\
 	   "adc{l} {$0,%0|%0,0}"				\
-	   : "+r" ((USItype) (x3)),				\
-	     "+&r" ((USItype) (x2)),				\
-	     "+&r" ((USItype) (x1)),				\
-	     "+&r" ((USItype) (x0))				\
+	   : "+r" __asm_output_check_type (USItype, x3),	\
+	     "+&r" __asm_output_check_type (USItype, x2),	\
+	     "+&r" __asm_output_check_type (USItype, x1),	\
+	     "+&r" __asm_output_check_type (USItype, x0)	\
 	   : "g" ((USItype) (i)))

             reply	other threads:[~2024-02-07 14:07 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-02-07 14:07 Adhemerval Zanella [this message]
  -- strict thread matches above, loose matches on Subject: below --
2024-04-17 20:07 Adhemerval Zanella
2024-04-02 15:54 Adhemerval Zanella
2024-02-09 17:32 Adhemerval Zanella
2024-01-29 17:57 Adhemerval Zanella
2023-12-21 18:54 Adhemerval Zanella
2023-09-28 17:52 Adhemerval Zanella

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