[Bug target/53988] [SH] tst Rm,Rn not used for QI/HImode

[olegendo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53988

Oleg Endo <olegendo at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|RESOLVED                    |REOPENED
   Last reconfirmed|                            |2014-12-29
         Resolution|FIXED                       |---
     Ever confirmed|0                           |1

--- Comment #4 from Oleg Endo <olegendo at gcc dot gnu.org> ---
The change in r192982 results in wrong code:

int test (short x, short* y, int z, int w)
{
  return x & y[0] ? z : w;
}

        mov.w   @r5,r1    // sign extended y[0], bits[31:16] = 1
        tst     r4,r1     // r4 bits [31:16] undefined
        bf      .L5
        mov     r7,r0
        rts
        nop
    .align 1
.L5:
        rts
        mov     r6,r0

The *tst<mode>_t_zero insns blindly accept subregs.  They have to check whether
both operands have been sign extended or at least one of them has been zero
extended (to mask out the unwanted high bits).