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From: Adhemerval Zanella <azanella@sourceware.org>
To: glibc-cvs@sourceware.org
Subject: [glibc/azanella/clang] stdlib: longlong.h: Do no use asm input cast for clang
Date: Wed, 17 Apr 2024 20:04:26 +0000 (GMT)	[thread overview]
Message-ID: <20240417200426.A96543858C52@sourceware.org> (raw)

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9a30e8cf4fa8d540b16cb08df3b6bd7fb3271131

commit 9a30e8cf4fa8d540b16cb08df3b6bd7fb3271131
Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Date:   Wed Sep 13 18:02:57 2023 -0300

    stdlib: longlong.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:
---
 stdlib/longlong.h | 48 ++++++++++++++++++++++++++++--------------------
 1 file changed, 28 insertions(+), 20 deletions(-)

diff --git a/stdlib/longlong.h b/stdlib/longlong.h
index 241b2f0f99..bcaa0cfcc6 100644
--- a/stdlib/longlong.h
+++ b/stdlib/longlong.h
@@ -57,6 +57,14 @@
 #define attribute_hidden
 #endif
 
+/* 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
+
 extern const UQItype __clz_tab[256] attribute_hidden;
 
 /* Define auxiliary asm macros.
@@ -230,16 +238,16 @@ extern UDItype __udiv_qrnnd (UDItype *, UDItype, UDItype, UDItype);
  && W_TYPE_SIZE == 32
 #define add_ssaaaa(sh, sl, ah, al, bh, bl) \
   __asm__ ("adds	%1, %4, %5\n\tadc	%0, %2, %3"		\
-	   : "=r" ((USItype) (sh)),					\
-	     "=&r" ((USItype) (sl))					\
+	   : "=r" __asm_output_check_type (USItype, sh),		\
+	     "=&r" __asm_output_check_type (USItype, sl)		\
 	   : "%r" ((USItype) (ah)),					\
 	     "rI" ((USItype) (bh)),					\
 	     "%r" ((USItype) (al)),					\
 	     "rI" ((USItype) (bl)) __CLOBBER_CC)
 #define sub_ddmmss(sh, sl, ah, al, bh, bl) \
   __asm__ ("subs	%1, %4, %5\n\tsbc	%0, %2, %3"		\
-	   : "=r" ((USItype) (sh)),					\
-	     "=&r" ((USItype) (sl))					\
+	   : "=r" __asm_output_check_type (USItype, sh),		\
+	     "=&r" __asm_output_check_type (USItype, sl)		\
 	   : "r" ((USItype) (ah)),					\
 	     "rI" ((USItype) (bh)),					\
 	     "r" ((USItype) (al)),					\
@@ -456,30 +464,30 @@ extern UDItype __umulsidi3 (USItype, USItype);
 #if (defined (__i386__) || defined (__i486__)) && W_TYPE_SIZE == 32
 #define add_ssaaaa(sh, sl, ah, al, bh, bl) \
   __asm__ ("add{l} {%5,%1|%1,%5}\n\tadc{l} {%3,%0|%0,%3}"		\
-	   : "=r" ((USItype) (sh)),					\
-	     "=&r" ((USItype) (sl))					\
+	   : "=r" __asm_output_check_type (USItype, sh),		\
+	     "=&r" __asm_output_check_type(USItype, sl)			\
 	   : "%0" ((USItype) (ah)),					\
 	     "g" ((USItype) (bh)),					\
 	     "%1" ((USItype) (al)),					\
 	     "g" ((USItype) (bl)))
 #define sub_ddmmss(sh, sl, ah, al, bh, bl) \
   __asm__ ("sub{l} {%5,%1|%1,%5}\n\tsbb{l} {%3,%0|%0,%3}"		\
-	   : "=r" ((USItype) (sh)),					\
-	     "=&r" ((USItype) (sl))					\
+	   : "=r" __asm_output_check_type (USItype, sh),		\
+	     "=&r" __asm_output_check_type (USItype, sl)		\
 	   : "0" ((USItype) (ah)),					\
 	     "g" ((USItype) (bh)),					\
 	     "1" ((USItype) (al)),					\
 	     "g" ((USItype) (bl)))
 #define umul_ppmm(w1, w0, u, v) \
   __asm__ ("mul{l} %3"							\
-	   : "=a" ((USItype) (w0)),					\
-	     "=d" ((USItype) (w1))					\
+	   : "=a" __asm_output_check_type (USItype, w0),		\
+	     "=d" __asm_output_check_type (USItype, w1)			\
 	   : "%0" ((USItype) (u)),					\
 	     "rm" ((USItype) (v)))
 #define udiv_qrnnd(q, r, n1, n0, dv) \
   __asm__ ("div{l} %4"							\
-	   : "=a" ((USItype) (q)),					\
-	     "=d" ((USItype) (r))					\
+	   : "=a" __asm_output_check_type (USItype, q),			\
+	     "=d" __asm_output_check_type (USItype, r)			\
 	   : "0" ((USItype) (n0)),					\
 	     "1" ((USItype) (n1)),					\
 	     "rm" ((USItype) (dv)))
@@ -492,30 +500,30 @@ extern UDItype __umulsidi3 (USItype, USItype);
 #if defined (__x86_64__) && W_TYPE_SIZE == 64
 #define add_ssaaaa(sh, sl, ah, al, bh, bl) \
   __asm__ ("add{q} {%5,%1|%1,%5}\n\tadc{q} {%3,%0|%0,%3}"		\
-	   : "=r" ((UDItype) (sh)),					\
-	     "=&r" ((UDItype) (sl))					\
+	   : "=r" __asm_output_check_type (UDItype, sh),		\
+	     "=&r" __asm_output_check_type (UDItype, sl)		\
 	   : "%0" ((UDItype) (ah)),					\
 	     "rme" ((UDItype) (bh)),					\
 	     "%1" ((UDItype) (al)),					\
 	     "rme" ((UDItype) (bl)))
 #define sub_ddmmss(sh, sl, ah, al, bh, bl) \
   __asm__ ("sub{q} {%5,%1|%1,%5}\n\tsbb{q} {%3,%0|%0,%3}"		\
-	   : "=r" ((UDItype) (sh)),					\
-	     "=&r" ((UDItype) (sl))					\
+	   : "=r" __asm_output_check_type (UDItype, sh),		\
+	     "=&r" __asm_output_check_type (UDItype, sl)		\
 	   : "0" ((UDItype) (ah)),					\
 	     "rme" ((UDItype) (bh)),					\
 	     "1" ((UDItype) (al)),					\
 	     "rme" ((UDItype) (bl)))
 #define umul_ppmm(w1, w0, u, v) \
   __asm__ ("mul{q} %3"							\
-	   : "=a" ((UDItype) (w0)),					\
-	     "=d" ((UDItype) (w1))					\
+	   : "=a" __asm_output_check_type (UDItype, w0),		\
+	     "=d" __asm_output_check_type (UDItype, w1)			\
 	   : "%0" ((UDItype) (u)),					\
 	     "rm" ((UDItype) (v)))
 #define udiv_qrnnd(q, r, n1, n0, dv) \
   __asm__ ("div{q} %4"							\
-	   : "=a" ((UDItype) (q)),					\
-	     "=d" ((UDItype) (r))					\
+	   : "=a" __asm_output_check_type (UDItype, q),			\
+	     "=d" __asm_output_check_type (UDItype, r)			\
 	   : "0" ((UDItype) (n0)),					\
 	     "1" ((UDItype) (n1)),					\
 	     "rm" ((UDItype) (dv)))

             reply	other threads:[~2024-04-17 20:04 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-17 20:04 Adhemerval Zanella [this message]
  -- strict thread matches above, loose matches on Subject: below --
2024-04-02 15:50 Adhemerval Zanella
2024-02-09 17:28 Adhemerval Zanella
2024-02-07 14:04 Adhemerval Zanella
2024-01-29 17:54 Adhemerval Zanella
2023-12-21 18:50 Adhemerval Zanella
2023-09-28 17:49 Adhemerval Zanella

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