[Bug rtl-optimization/60260] New: MIPS sign extension issue

[jan.smets@alcatel-lucent.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60260

            Bug ID: 60260
           Summary: MIPS sign extension issue
           Product: gcc
           Version: 4.8.2
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jan.smets@alcatel-lucent.com

GCC 4.8.2 

mips-wrs-vxworks
 -c test.c -o test -Wall -O2 -mabi=32


int main()
{   
    volatile unsigned int * ptr;
    unsigned int end = 0x7fbfff80U;
    unsigned int * eptr = (unsigned int*)0x80000000U;

    #define CACHE_LINE_SIZE 32
    for (ptr = (volatile unsigned int *) end; ptr < eptr; ptr +=
CACHE_LINE_SIZE / sizeof(*ptr))
    {   
        //printf("ptr=%p\n", ptr);
        *ptr = *ptr;
    }
    return 0;
}




00000000 <main>:
   0:   3c027fbf        lui     v0,0x7fbf
   4:   3442ff80        ori     v0,v0,0xff80
   8:   3c048000        lui     a0,0x8000
   c:   8c430000        lw      v1,0(v0)           .. then when v0 reaches
7FFFFFE0 ... 
  10:   24420020        addiu   v0,v0,32           result is 8000.0000 and
signed extended ?
  14:   ac43ffe0        sw      v1,-32(v0)         <======= crash here on addr
0xFFFFFFFF.7FFFFFE0
  18:   1444fffc        bne     v0,a0,c <main+0xc>
  1c:   00000000        nop
  20:   03e00008        jr      ra
  24:   00001021        move    v0,zero

When -fno-schedule-insns -fno-schedule-insns2 is used then the add is done
after the load/stores. (Which is what GCC 4.6 does)
(Or daddiu may solve this too I think)