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Subject: [Bug target/51244] [SH] Inefficient conditional branch and code around T bit
Date: Sun, 23 Sep 2012 21:42:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51244

--- Comment #53 from Oleg Endo <olegendo at gcc dot gnu.org> 2012-09-23 21:41:55 UTC ---
Another case that seems to go awry:

int test_1 (int a, int b, int c, int* d)
{
  bool x = a == 0;
  d[2] = !x;

  return x ? b : c;
}

-O2 -m4:
        tst     r4,r4
        mov     #1,r1
        movt    r0
        xor     r0,r1
        tst     r0,r0
        bt/s    .L5
        mov.l   r1,@(8,r7)
        mov     r5,r6
.L5:
        rts
        mov     r6,r0

This should be something like:
        tst     r4,r4
        movt    r0
        xor     #1,r0
        bf/s    .L5
        mov.l   r1,@(8,r7)
        mov     r5,r6
.L5:
        rts
        mov     r6,r0


-O2 -m2a:
        tst     r4,r4
        movt    r0
        mov     #1,r1
        xor     r0,r1
        mov.l   r1,@(8,r7)
        tst     r0,r0
        bf      .L6
        mov     r6,r0
        rts/n
    .align 1
.L6:
        rts
        mov     r5,r0

This should be:
        tst     r4,r4
        movrt   r1
        mov.l   r1,@(8,r7)
        bt      .L6
        mov     r6,r0
        rts/n
    .align 1
.L6:
        rts
        mov     r5,r0