Re: [patch] fix rs6000-power2-2.c

[Geoffrey Keating <geoffk at geoffk dot org>]

Eric Christopher <echristo@apple.com> writes:

> This patch fixes the testcase rs6000-power2-2.c which tests for
> generation of the TFmode move instructions. We were failing the
> testcase because while we would generate the instruction in peephole2
> we would recognize the splitter version of the pattern and split just
> before code generation.
> 
> Tested on ppc-darwin8, though this isn't as helpful since it isn't a
> power2 architecture machine. No regressions, fixes the aforementioned
> testcases. OK?
> 
> 2005-08-08  Eric Christopher  <echristo@apple.com>
> 
>          * config/rs6000/rs6000.md (*movtf_internal): Disable pattern
>          for power2.

I suspect this breaks power2, because it'll suddenly have no way to do
certain TFmode moves.  David, could you try this on a POWER2 machine?
I don't have one...

> Also while I was at it I rewrote mems_ok_for_quad_peep since it
> seemed a bit confusingly written. This code looks a bit cleaner, and
> still passes all of the tests. Tested the same way. OK?
> 
> 2005-08-08  Eric Christopher  <echristo@apple.com>
> 
>         * config/rs6000/rs6000.c (mems_ok_for_quad_peep): Rewrite.

(see below for comments on this part)

> -eric
> 
> Index: rs6000.md
> ===================================================================
> RCS file: /cvs/gcc/gcc/gcc/config/rs6000/rs6000.md,v
> retrieving revision 1.392
> diff -u -p -w -r1.392 rs6000.md
> --- rs6000.md   15 Jul 2005 01:44:34 -0000      1.392
> +++ rs6000.md   8 Aug 2005 23:16:29 -0000
> @@ -7844,11 +7844,19 @@
> ; It's important to list the o->f and f->o moves before f->f because
> ; otherwise reload, given m->f, will try to pick f->f and reload it,
> ; which doesn't make progress.  Likewise r->Y must be before r->r.
> +; Do not recognize this under TARGET_POWER2 since we have other
> instructions to
> +; match this and do not want to split.
> (define_insn_and_split "*movtf_internal"
>     [(set (match_operand:TF 0 "nonimmediate_operand" "=o,f,f,r,Y,r")
>          (match_operand:TF 1 "input_operand"         "f,o,f,YGHF,r,r"))]
>     "(DEFAULT_ABI == ABI_AIX || DEFAULT_ABI == ABI_DARWIN)
>      && TARGET_HARD_FLOAT && TARGET_FPRS && TARGET_LONG_DOUBLE_128
> +   && !(TARGET_POWER2
> +       && gpc_reg_operand (operands[0], TFmode)
> +       && memory_operand (operands[1], TFmode))
> +   && !(TARGET_POWER2
> +       && memory_operand (operands[0], TFmode)
> +       && gpc_reg_operand (operands[1], TFmode))
>      && (gpc_reg_operand (operands[0], TFmode)
>          || gpc_reg_operand (operands[1], TFmode))"
>     "#"
> 
> Index: rs6000.c
> ===================================================================
> RCS file: /cvs/gcc/gcc/gcc/config/rs6000/rs6000.c,v
> retrieving revision 1.858
> diff -u -p -w -r1.858 rs6000.c
> --- rs6000.c    8 Aug 2005 16:36:19 -0000       1.858
> +++ rs6000.c    8 Aug 2005 23:27:08 -0000
> @@ -9647,8 +9647,8 @@ int
> mems_ok_for_quad_peep (rtx mem1, rtx mem2)
> {
>     rtx addr1, addr2;
> -  unsigned int reg1;
> -  int offset1;
> +  unsigned int reg1, reg2;
> +  int offset1, offset2;
>     /* The mems cannot be volatile.  */
>     if (MEM_VOLATILE_P (mem1) || MEM_VOLATILE_P (mem2))
> @@ -9681,23 +9681,36 @@ mems_ok_for_quad_peep (rtx mem1, rtx mem
>         offset1 = 0;
>       }
> -  /* Make sure the second address is a (mem (plus (reg) (const_int)))
> -     or if it is (mem (reg)) then make sure that offset1 is -8 and
> the same
> -     register as addr1.  */
> -  if (offset1 == -8 && GET_CODE (addr2) == REG && reg1 == REGNO
> (addr2))
> -    return 1;
> -  if (GET_CODE (addr2) != PLUS)
> +  /* And now for the second addr.  */
> +  if (GET_CODE (addr2) == PLUS)
> +    {
> +      /* If not a REG, return zero.  */
> +      if (GET_CODE (XEXP (addr2, 0)) != REG)
>       return 0;
> -
> -  if (GET_CODE (XEXP (addr2, 0)) != REG
> -      || GET_CODE (XEXP (addr2, 1)) != CONST_INT)
> +      else
> +       {
> +         reg2 = REGNO (XEXP (addr2, 0));
> +         /* The offset must be constant. */
> +         if (GET_CODE (XEXP (addr2, 1)) != CONST_INT)
>       return 0;
> 
>     /* All the tests passed.  addr1 and addr2 are valid for lfq or stfq

Maybe this is just my eyes, but I count two added '{' and yet no added '}'.