On Sun, May 16, 2021 at 11:06 PM apinski--- via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> From: Andrew Pinski <apin...@marvell.com>
>
> Instead of some of the more manual optimizations inside phi-opt,
> it would be good idea to do a lot of the heavy lifting inside match
> and simplify instead. In the process, this moves the three simple
> A?CST1:CST2 (where CST1 or CST2 is zero) simplifications.
>
> OK? Boostrapped and tested on x86_64-linux-gnu with no regressions.
>
> Thanks,
> Andrew Pinski
>
> gcc:
> * match.pd (A?CST1:CST2): Add simplifcations for A?0:+-1, A?+-1:0,
> A?POW2:0 and A?0:POW2.
> ---
> gcc/match.pd | 37 +++++++++++++++++++++++++++++++++++++
> 1 file changed, 37 insertions(+)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 10503b97ab5..844f7dd5f87 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -3711,6 +3711,43 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> (if (integer_all_onesp (@1) && integer_zerop (@2))
> @0))))
>
> +/* A few simplifications of "a ? CST1 : CST2". */
> +/* NOTE: Only do this on gimple as the if-chain-to-switch
> + optimization depends on the gimple to have if statements in it. */
> +#if GIMPLE
> +(simplify
> + (cond @0 INTEGER_CST@1 INTEGER_CST@2)
> + (switch
> + (if (integer_zerop (@2))
> + (switch
> + /* a ? 1 : 0 -> a if 0 and 1 are integral types. */
> + (if (integer_onep (@1))
> + (convert (convert:boolean_type_node @0)))
> + /* a ? -1 : 0 -> -a. */
> + (if (integer_all_onesp (@1))
can you use integer_minus_onep here since you're using (negate ...) to
produce it?
> + (negate (convert (convert:boolean_type_node @0))))
> + /* a ? powerof2cst : 0 -> a << (log2(powerof2cst)) */
> + (if (!POINTER_TYPE_P (type) && integer_pow2p (@1))
> + (with {
> + tree shift = build_int_cst (integer_type_node, wi::exact_log2
> (wi::to_wide (@1)));
> + }
> + (lshift (convert (convert:boolean_type_node @0)) { shift; })))))
> + (if (integer_zerop (@1))
> + (switch
> + /* a ? 0 : 1 -> !a. */
> + (if (integer_onep (@2))
> + (convert (bit_not:boolean_type_node (convert:boolean_type_node @0))))
> + /* a ? -1 : 0 -> -(!a). */
> + (if (integer_all_onesp (@2))
> + (negate (convert (bit_not:boolean_type_node (convert:boolean_type_node
> @0)))))
Likewise.
I think the second :boolean_type_node is redundant.
> + /* a ? powerof2cst : 0 -> (!a) << (log2(powerof2cst)) */
> + (if (!POINTER_TYPE_P (type) && integer_pow2p (@2))
> + (with {
> + tree shift = build_int_cst (integer_type_node, wi::exact_log2
> (wi::to_wide (@2)));
> + }
> + (lshift (convert (bit_not:boolean_type_node (convert:boolean_type_node
> @0))) { shift; })))))))
likewise.
Otherwise looks OK (with the latent issue fixed).
Thanks,
Richard.
> +#endif
> +
> /* Simplification moved from fold_cond_expr_with_comparison. It may also
> be extended. */
> /* This pattern implements two kinds simplification:
> --
> 2.27.0
>
