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Date: Fri, 3 Sep 2021 16:44:54 -0500
From: Segher Boessenkool <segher@kernel.crashing.org>
To: Xionghu Luo <luoxhu@linux.ibm.com>
Cc: will schmidt <will_schmidt@vnet.ibm.com>, gcc-patches@gcc.gnu.org,
 wschmidt@linux.ibm.com, dje.gcc@gmail.com, linkw@gcc.gnu.org
Subject: Re: Ping ^ 2: [PATCH] rs6000: Expand fmod and remainder when built
 with fast-math [PR97142]
Message-ID: <20210903214454.GO1583@gate.crashing.org>
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Hi!

On Fri, Sep 03, 2021 at 10:31:24AM +0800, Xionghu Luo wrote:
> fmod/fmodf and remainder/remainderf could be expanded instead of library
> call when fast-math build, which is much faster.

Thank you very much for this patch.

Some trivial comments if you haven't commmitted it yet:

> +(define_expand "fmod<mode>3"
> +  [(use (match_operand:SFDF 0 "gpc_reg_operand"))
> +	(use (match_operand:SFDF 1 "gpc_reg_operand"))
> +	(use (match_operand:SFDF 2 "gpc_reg_operand"))]
> +  "TARGET_HARD_FLOAT
> +  && TARGET_FPRND
> +  && flag_unsafe_math_optimizations"

It should have one extra space before each && here:

  "TARGET_HARD_FLOAT
   && TARGET_FPRND
   && flag_unsafe_math_optimizations"

(so that everything inside of the string aligns).

> +(define_expand "remainder<mode>3"

(same here).

> +/* { dg-final { scan-assembler-not {\mbl fmod\M} } } */
> +/* { dg-final { scan-assembler-not {\mbl fmodf\M} } } */
> +/* { dg-final { scan-assembler-not {\mbl remainder\M} } } */
> +/* { dg-final { scan-assembler-not {\mbl remainderf\M} } } */

These are negative tests, so won't spuriously fail, but this does not
test for the function prefixes we can have.  See
gcc.target/powerpc/builtins-1.c for example.

Again, thank you, and thanks to everyone else for the patch review
action :-)


Segher