Hi -

on mipsel, I've found a case where gcc without options produces
bad code, and "gcc -O2" does well:

A signal handler:
void
sigfpe(int s, siginfo_t *si, void *c)
{
        int code = si->si_code;

        printf("caught code %x\n", code);
        signal_caught = 1;
        exit (0);
}

gets translated without gcc flags to:

sigfpe:
        .frame  $fp,48,$31              # vars= 8, regs= 3/0, args= 16, extra= 
8
        .mask   0xd0000000,-8
        .fmask  0x00000000,0
        .set    noreorder
        .cpload $25
        .set    reorder
        subu    $sp,$sp,48
        .cprestore 16
        sw      $31,40($sp)
        sw      $fp,36($sp)
        sw      $28,32($sp)
        move    $fp,$sp
        sw      $4,48($fp)
        sw      $5,52($fp)
        sw      $6,56($fp)
        lw      $2,52($fp)
        lw      $2,4($2)
        sw      $2,24($fp)
        la      $4,$LC10
        lw      $5,24($fp)
        la      $25,printf
        jal     $31,$25
        li      $2,1                    # 0x1
[...],

with -O2 this is:

sigfpe:
        .frame  $sp,32,$31              # vars= 0, regs= 2/0, args= 16, extra= 
8
        .mask   0x90000000,-4
        .fmask  0x00000000,0
        .set    noreorder
        .cpload $25
        .set    reorder
        subu    $sp,$sp,32
        .cprestore 16
        sw      $31,28($sp)
        sw      $28,24($sp)
        lw      $5,4($5)
        la      $4,$LC10
        la      $25,printf
        jal     $31,$25
        li      $2,1                    # 0x1
[...]

best regards
Matthias