[glibc/vineet/arc-glibc-2.30-time_t-32-bit] gcc PR 88409: miscompilation due to missing cc clobber in longlong.h macros

[glibc/vineet/arc-glibc-2.30-time_t-32-bit] gcc PR 88409: miscompilation due to missing cc clobber in longlong.h macros

[Vineet Gupta]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=76db6bd7913b0bd452eb0cd7fe11899abffe90ab

commit 76db6bd7913b0bd452eb0cd7fe11899abffe90ab
Author: Vineet Gupta <vgupta@synopsys.com>
Date:   Thu Mar 28 15:24:35 2019 -0700

    gcc PR 88409: miscompilation due to missing cc clobber in longlong.h macros
    
    simple test such as below was failing.
    
    | void main(int argc, char *argv[])
    | {
    |    size_t total_time = 115424;                       // expected 115.424
    |    double secs = (double)total_time/(double)1000;
    |    printf("%s %d %lf\n", "secs", total_time, secs);  // prints 113.504
    |    printf("%d\n", (size_t)secs);
    | }
    
    The printf eventually called into glibc stdlib/divrem.c:__mpn_divrem()
    which uses the __arc__ specific inline asm macros from longlong.h which
    were causing miscompilation.
    
    include/
    2019-03-28  Vineet Gupta <vgupta@synopsys.com>
    
            PR 89877
    
            * longlong.h [__arc__] (add_ssaaaa): Add cc clobber
            (sub_ddmmss): Likewise.
    
    Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

Diff:
---
 stdlib/longlong.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/stdlib/longlong.h b/stdlib/longlong.h
index 3dd8dc3aa8..1f0ce42042 100644
--- a/stdlib/longlong.h
+++ b/stdlib/longlong.h
@@ -199,7 +199,8 @@ extern UDItype __udiv_qrnnd (UDItype *, UDItype, UDItype, UDItype);
 	   : "%r" ((USItype) (ah)),					\
 	     "rICal" ((USItype) (bh)),					\
 	     "%r" ((USItype) (al)),					\
-	     "rICal" ((USItype) (bl)))
+	     "rICal" ((USItype) (bl))					\
+	   : "cc")
 #define sub_ddmmss(sh, sl, ah, al, bh, bl) \
   __asm__ ("sub.f	%1, %4, %5\n\tsbc	%0, %2, %3"		\
 	   : "=r" ((USItype) (sh)),					\
@@ -207,7 +208,8 @@ extern UDItype __udiv_qrnnd (UDItype *, UDItype, UDItype, UDItype);
 	   : "r" ((USItype) (ah)),					\
 	     "rICal" ((USItype) (bh)),					\
 	     "r" ((USItype) (al)),					\
-	     "rICal" ((USItype) (bl)))
+	     "rICal" ((USItype) (bl))					\
+	   : "cc")
 
 #define __umulsidi3(u,v) ((UDItype)(USItype)u*(USItype)v)
 #ifdef __ARC_NORM__