Re: [PATCH v4, rs6000] Enable have_cbranchcc4 on rs6000

["Kewen.Lin" <linkw@linux.ibm.com>]

Hi Haochen,

on 2022/12/8 11:08, HAO CHEN GUI wrote:
> Hi,
>   This patch enables "have_cbranchcc4" on rs6000 by defining
> a "cbranchcc4" expander. "have_cbrnachcc4" is a flag in ifcvt.cc
> to indicate if branch by CC bits is invalid or not. With this
> flag enabled, some branches can be optimized to conditional
> moves.
> 
>   Compared to last version, the main changes are on the test
> cases. Test case is renamed and comments are modified.
> 
>   Bootstrapped and tested on powerpc64-linux BE and LE with no
> regressions. Is this okay for trunk? Any recommendations? Thanks
> a lot.
> 

This patch is OK, thanks!

BR,
Kewen

> BR
> Gui Haochen
> 
> ChangeLog
> 2022-12-07  Haochen Gui <guihaoc@linux.ibm.com>
> 
> gcc/
> 	* config/rs6000/rs6000.md (cbranchcc4): New expander.
> 
> gcc/testsuite
> 	* gcc.target/powerpc/cbranchcc4-1.c: New.
> 	* gcc.target/powerpc/cbranchcc4-2.c: New.
> 
> patch.diff
> diff --git a/gcc/config/rs6000/rs6000.md b/gcc/config/rs6000/rs6000.md
> index e9e5cd1e54d..d7ddd96cc70 100644
> --- a/gcc/config/rs6000/rs6000.md
> +++ b/gcc/config/rs6000/rs6000.md
> @@ -11932,6 +11932,16 @@ (define_expand "cbranch<mode>4"
>    DONE;
>  })
> 
> +(define_expand "cbranchcc4"
> +  [(set (pc)
> +	(if_then_else (match_operator 0 "branch_comparison_operator"
> +			[(match_operand 1 "cc_reg_operand")
> +			 (match_operand 2 "zero_constant")])
> +		      (label_ref (match_operand 3))
> +		      (pc)))]
> +  ""
> +  "")
> +
>  (define_expand "cstore<mode>4_signed"
>    [(use (match_operator 1 "signed_comparison_operator"
>           [(match_operand:P 2 "gpc_reg_operand")
> diff --git a/gcc/testsuite/gcc.target/powerpc/cbranchcc4-1.c b/gcc/testsuite/gcc.target/powerpc/cbranchcc4-1.c
> new file mode 100644
> index 00000000000..6c2cd130b6d
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/cbranchcc4-1.c
> @@ -0,0 +1,15 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2" } */
> +
> +/* Verify there is no ICE with cbranchcc4 enabled.  */
> +
> +int foo (double d)
> +{
> +  if (d == 0.0)
> +    return 0;
> +
> +  d = ((d) >= 0 ? (d) : -(d));
> +
> +  if (d < 1.0)
> +    return 1;
> +}
> diff --git a/gcc/testsuite/gcc.target/powerpc/cbranchcc4-2.c b/gcc/testsuite/gcc.target/powerpc/cbranchcc4-2.c
> new file mode 100644
> index 00000000000..528ba1a878d
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/powerpc/cbranchcc4-2.c
> @@ -0,0 +1,11 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -fdump-rtl-ce1" } */
> +/* { dg-final { scan-rtl-dump "noce_try_store_flag_constants" "ce1" } } */
> +
> +/* The inner branch should be detected by ifcvt then be converted to a setcc
> +   with a plus by noce_try_store_flag_constants.  */
> +
> +int test (unsigned int a, unsigned int b)
> +{
> +    return (a < b ? 0 : (a > b ? 2 : 1));
> +}