Re: [PATCH v2] RISC-V: No extensions for SImode min/max against safe constant

[Jeff Law <jeffreyalaw@gmail.com>]

On 11/8/22 17:06, Philipp Tomsich wrote:
> Optimize the common case of a SImode min/max against a constant
> that is safe both for sign- and zero-extension.
> E.g., consider the case
>    int f(unsigned int* a)
>    {
>      const int C = 1000;
>      return *a * 3 > C ? C : *a * 3;
>    }
> where the constant C will yield the same result in DImode whether
> sign- or zero-extended.
>
> This should eventually go away once the lowering to RTL smartens up
> and considers the precision/signedness and the value-ranges of the
> operands to MIN_EXPR nad MAX_EXPR.
>
> gcc/ChangeLog:
>
> 	* config/riscv/bitmanip.md (*minmax): Additional pattern for
>            min/max against constants that are extension-invariant.
> 	* config/riscv/iterators.md (minmax_optab): Add an iterator
> 	  that has only min and max rtl.
>
> gcc/testsuite/ChangeLog:
>
> 	* gcc.target/riscv/zbb-min-max-02.c: New test.

Ok

jeff