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Re: Fix for 56175

On Wed, Feb 20, 2013 at 1:00 PM, Yuri Rumyantsev <> wrote:
> Hi All,
> This patch is aimed to recognize (A & C) ^ (B & C) -> (A ^ B) & C
> pattern in simpify_bitwise_binary for short integer types.
> The fix is very simple - we simply turn off short type sinking at the
> first pass of forward propagation allows to get
> +10% speedup for important benchmark Coremark 1.0 at x86 Atom and
> +5-7% for other x86 platforms too.
> Bootstrapping and regression testing were successful on x86-64.
> Is it Ok for trunk?

It definitely needs a comment before the checks.

Also I think it simply shows that the code is placed at the wrong spot.
Simply moving it down in simplify_bitwise_binary to be done the very last
should get both of the effects done.

Can you rework the patch according to that?

You also miss a testcase, we should make sure to not regress again here.


> ChangeLog.
> 2013-02-20  Yuri Rumyantsev  <>
>         PR tree-optimization/56175
>         * tree-ssa-forwprop.c (simplify_bitwise_binary) : Avoid type sinking
>         at 1st forwprop pass to recognize (A & C) ^ (B & C) -> (A ^ B) & C
>         for short integer types.

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