[PATCH] Fix aarch64_simd_reg_or_zero predicate (PR fortran/84565)

[James Greenhalgh]

On Tue, Feb 27, 2018 at 02:22:22PM +0000, Richard Sandiford wrote:
> Jakub Jelinek <jakub@redhat.com> writes:
> > Hi!
> >
> > The following testcase ICEs, because the aarch64_cmeqdf instruction
> > starting with r256612 no longer accepts CONST0_RTX (E_DFmode) as
> > valid argument, but the expander generates it anyway.
> >
> > The bug has been introduced during the addition of aarch64_simd_imm_zero
> > and aarch64_simd_or_scalar_imm_zero predicates, before the predicate
> > used to be:
> > (define_predicate "aarch64_simd_reg_or_zero"
> >   (and (match_code "reg,subreg,const_int,const_double,const_vector")
> >        (ior (match_operand 0 "register_operand")
> >            (ior (match_test "op == const0_rtx")
> >                 (match_test "aarch64_simd_imm_zero_p (op, mode)")))))
> > with
> > bool
> > aarch64_simd_imm_zero_p (rtx x, machine_mode mode)
> > {
> >   return x == CONST0_RTX (mode);
> > }
> > and so matched not just const,const_vector zeros, but also
> > const_int zero (that is through op == const0_rtx) and const_double
> > zero too.
> 
> Thanks for fixing this.
> 
> > Bootstrapped/regtested on aarch64-linux (scratch Fedora gcc 8 package build
> > with the patch applied), ok for trunk?
> >
> > 2018-02-27  Jakub Jelinek  <jakub@redhat.com>
> >
> > 	PR fortran/84565
> > 	* config/aarch64/predicates.md (aarch64_simd_reg_or_zero): Use
> > 	aarch64_simd_or_scalar_imm_zero rather than aarch64_simd_imm_zero.
> >
> > 	* gfortran.dg/pr84565.f90: New test.
> >
> > --- gcc/config/aarch64/predicates.md.jj	2018-02-06 13:13:06.305751221 +0100
> > +++ gcc/config/aarch64/predicates.md	2018-02-26 16:30:01.902195208 +0100
> > @@ -395,7 +395,7 @@ (define_predicate "aarch64_simd_reg_or_z
> >    (and (match_code "reg,subreg,const_int,const_double,const,const_vector")
> >         (ior (match_operand 0 "register_operand")
> >  	    (match_test "op == const0_rtx")
> > -	    (match_operand 0 "aarch64_simd_imm_zero"))))
> > +	    (match_operand 0 "aarch64_simd_or_scalar_imm_zero"))))
> 
> I think this makes the match_test on the line above redundant.
> 
> LGTM otherwise (but I can't approve).  We should probably clean up
> the predicates so that the zero checks are more consistent.  genrecog
> could probably help by ignoring predicate codes that obviously don't
> apply (CONST_INT for vectors, CONST_VECTOR for ints, etc.).  But that's
> obviously all stage 1 stuff.

OK.

Thanks,
James