Re: [PATCH]: Expand isinf() as x87 asm

["Richard Guenther" <richard dot guenther at gmail dot com>]

On 1/31/07, Uros Bizjak <ubizjak@gmail.com> wrote:
> Hello!
>
> This patch expands isinf() into inline x87 asm.
>
> Following testcase:
> --cut here--
> int test(double a)
> {
>         return isinf(a + 2.0);
> }
> --cut here--
>
> compiles to (gcc -O2 -fomit-frame-pointer):
> test:
>         flds    .LC0
>         faddl   4(%esp)
>         fxam
>         fnstsw  %ax
>         fstp    %st(0)
>         andb    $69, %ah
>         cmpb    $5, %ah
>         sete    %al
>         movzbl  %al, %eax
>         ret
>
> Patch was regression tested on i686-pc-linux-gnu for all default languages.
>
> OK for SVN? (Patch needs middle-end approval.)

The middle-end parts are ok - can you open a PR for the missed-optimization
with SSE math?

Thanks,
Richard.

> 2007-01-31  Uros Bizjak  <ubizjak@gmail.com>
>
>         * optabs.h (enum optab_index): Add new OTI_isinf.
>         (isinf_optab): Define corresponding macro.
>         * optabs.c (init_optabs): Initialize isinf_optab.
>         * genopinit.c (optabs): Implement isinf_optab using isinf?f2
>         patterns.
>         * builtins.c (mathfn_built_in): Handle BUILT_IN_ISINF{,F,L}.
>         (expand_builtin_interclass_mathfn): Expand BUILT_IN_ISINF{,F,L}
>         using isinf_optab.
>         (expand_builtin): Expand BUILT_IN_ISINF{,F,L} using
>         expand_builtin_interclass_mathfn.
>         * reg_stack.c (subst_stack_regs_pat): Handle UNSPEC_FXAM.
>         * config/i386/i386.md (UNSPEC_FXAM): New constant.
>         (fxam<mode>2_i387): New insn pattern.
>         (isinf<mode>2) New expander to implement isinf, isinff and isinfl
>         built-in functions as x87 inline asm.