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* [Bug c/11965] New: On SPARC, gcc produces invalid assembler code for a shift << 32 operation
@ 2003-08-18 12:41 jk at tools dot de
  2003-08-18 17:35 ` [Bug c/11965] " falk at debian dot org
                   ` (7 more replies)
  0 siblings, 8 replies; 9+ messages in thread
From: jk at tools dot de @ 2003-08-18 12:41 UTC (permalink / raw)
  To: gcc-bugs

PLEASE REPLY TO gcc-bugzilla@gcc.gnu.org ONLY, *NOT* gcc-bugs@gcc.gnu.org.

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11965

           Summary: On SPARC, gcc produces invalid assembler code for a
                    shift << 32 operation
           Product: gcc
           Version: 3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: jk at tools dot de
                CC: gcc-bugs at gcc dot gnu dot org
 GCC build triplet: sparc-sun-solaris2.8
  GCC host triplet: sparc-sun-solaris2.8
GCC target triplet: sparc-sun-solaris2.8

GCC 3.3 on Solaris SPARC produces invalid assembler code, for shift operator
shifting 32 bits.

GCC 3.3 is compiled to use the system's assembler, /usr/ccs/bin/as


To reproduce the issue (admitted, this code has undefined behaviour):

% cat shift.c

#if __GNUC__
#define ATTR_ALWAYS_INLINE __attribute__ ((__always_inline__))
#else
#define ATTR_ALWAYS_INLINE
#endif


static ATTR_ALWAYS_INLINE unsigned
put_bits(int n, unsigned int value)
{
        return value << n;
}

main()
{
        unsigned val = 1;
        int i;

        for (i = 0; i < 4; i++)
                val = put_bits(32, val);

        printf("val=%x\n", val);
}

% gcc -O3 -mcpu=ultrasparc -o shift shift.c
/usr/ccs/bin/as: "/tmp/cc0VFu29.s", line 20: error: shift count negative or too
big: 32


Looking at the generated assembler source...

% gcc -O3 -mcpu=ultrasparc -S shift.c

... there's a shift instruction with a constant shift count of 32, where the
immediate shift count is restricted to the range 0 .. 31 on SPARC:

       sll     %o1, 32, %o1


The same code used to compile with gcc 3.2 and erlier, and it does compile with
gcc 3.3 at optimization level -O2 or when option -mcpu=ultrasparc is not used.


^ permalink raw reply	[flat|nested] 9+ messages in thread
end of thread, other threads:[~2003-09-10 13:05 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2003-08-18 12:41 [Bug c/11965] New: On SPARC, gcc produces invalid assembler code for a shift << 32 operation jk at tools dot de
2003-08-18 17:35 ` [Bug c/11965] " falk at debian dot org
2003-08-19 20:04 ` martin at netbsd dot org
2003-08-23  1:22 ` dhazeghi at yahoo dot com
2003-08-23 14:24 ` [Bug target/11965] [3.3/3.4 Regression] " pinskia at gcc dot gnu dot org
2003-09-09 14:51 ` [Bug target/11965] [3.3/3.4 Regression] " ebotcazou at gcc dot gnu dot org
2003-09-10 12:59 ` cvs-commit at gcc dot gnu dot org
2003-09-10 13:04 ` cvs-commit at gcc dot gnu dot org
2003-09-10 13:05 ` ebotcazou at gcc dot gnu dot org

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