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Re: [PATCH][ARM] PR 65694: Properly sign-extend large numbers before passing to GEN_INT in arm_canonicalize_comparison
- From: Jakub Jelinek <jakub at redhat dot com>
- To: Kyrill Tkachov <kyrylo dot tkachov at arm dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, Ramana Radhakrishnan <ramana dot radhakrishnan at arm dot com>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>
- Date: Fri, 10 Apr 2015 10:57:20 +0200
- Subject: Re: [PATCH][ARM] PR 65694: Properly sign-extend large numbers before passing to GEN_INT in arm_canonicalize_comparison
- Authentication-results: sourceware.org; auth=none
- References: <55278AC7 dot 9070807 at arm dot com>
- Reply-to: Jakub Jelinek <jakub at redhat dot com>
On Fri, Apr 10, 2015 at 09:33:11AM +0100, Kyrill Tkachov wrote:
> 2015-04-09 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
>
Missing
PR target/65694
line here.
> * config/arm/arm.c (arm_canonicalize_comparison): Use ARM_SIGN_EXTEND
> when creating +1 values for SImode and trunc_int_for_mode for similar
> DImode operations.
>
> 2015-04-09 Kyrylo Tkachov <kyrylo.tkachov@arm.com>
>
Ditto.
> * g++.dg/torture/pr65694.C: New test.
> diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
> index 369cb67..5342b33 100644
> --- a/gcc/config/arm/arm.c
> +++ b/gcc/config/arm/arm.c
> @@ -4984,7 +4984,7 @@ arm_canonicalize_comparison (int *code, rtx *op0, rtx *op1,
> if (i != maxval
> && arm_const_double_by_immediates (GEN_INT (i + 1)))
> {
> - *op1 = GEN_INT (i + 1);
> + *op1 = GEN_INT (trunc_int_for_mode (i + 1, DImode));
> *code = *code == GT ? GE : LT;
> return;
> }
> @@ -4994,7 +4994,7 @@ arm_canonicalize_comparison (int *code, rtx *op0, rtx *op1,
> if (i != ~((unsigned HOST_WIDE_INT) 0)
> && arm_const_double_by_immediates (GEN_INT (i + 1)))
> {
> - *op1 = GEN_INT (i + 1);
> + *op1 = GEN_INT (trunc_int_for_mode (i + 1, DImode));
The above two aren't strictly necessary, HOST_WIDE_INT is always 64-bit, so
is DImode, and GEN_INT takes HOST_WIDE_INT.
You haven't changed it in the GEN_INT (i + 1) calls passed to
arm_const_double_by_immediates anyway.
I'd think you can leave those changes to cleanup in stage1 if desirable.
> @@ -5047,7 +5047,7 @@ arm_canonicalize_comparison (int *code, rtx *op0, rtx *op1,
> if (i != maxval
> && (const_ok_for_arm (i + 1) || const_ok_for_arm (-(i + 1))))
> {
> - *op1 = GEN_INT (i + 1);
> + *op1 = GEN_INT (ARM_SIGN_EXTEND (i + 1));
> *code = *code == GT ? GE : LT;
> return;
> }
> @@ -5069,7 +5069,7 @@ arm_canonicalize_comparison (int *code, rtx *op0, rtx *op1,
> if (i != ~((unsigned HOST_WIDE_INT) 0)
> && (const_ok_for_arm (i + 1) || const_ok_for_arm (-(i + 1))))
> {
> - *op1 = GEN_INT (i + 1);
> + *op1 = GEN_INT (ARM_SIGN_EXTEND (i + 1));
> *code = *code == GTU ? GEU : LTU;
> return;
> }
This looks ok to me, but I'll defer the final word to ARM maintainers.
That said, the ARM_SIGN_EXTEND macro could very well use some cleanup too
now that HOST_WIDE_INT is always 64-bit and one can e.g. use
HOST_WIDE_INT_{U,}C macros to build large constants.
Jakub