On Mon, May 18, 2026 at 8:08 AM H.J. Lu <[email protected]> wrote:
>
> On Mon, May 18, 2026 at 1:56 PM Richard Biener
> <[email protected]> wrote:
> >
> > On Mon, May 18, 2026 at 4:25 AM Liu, Hongtao <[email protected]> wrote:
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: H.J. Lu <[email protected]>
> > > > Sent: Monday, May 18, 2026 5:52 AM
> > > > To: GCC Patches <[email protected]>; Uros Bizjak
> > > > <[email protected]>; Liu, Hongtao <[email protected]>
> > > > Subject: [PATCH] x86: Don't inline memmove for -Os
> > > >
> > > > OK for master and backport to GCC 16?
> > > Ok.
> > > >
> > > > Thanks.
> > > >
> > > > --
> > > > H.J.
> > > > ---
> > > > Update ix86_expand_movmem to return false if 
> > > > optimize_function_for_size_p
> > > > returns true to avoid inlining memmove for -Os.
> >
> > I think you should use optimize_insn_for_size_p instead.
>
> Do you have a testcase to show that it makes a difference?

It will make a difference with PGO, cold code should be optimized for size.
Another testcase would be -O2 with a path ending in abort(), so prediction
makes it cold.

> > > >
> > > > gcc/
> > > >
> > > > PR target/125355
> > > > * config/i386/i386-expand.cc (ix86_expand_movmem): Return false for -Os.
> > > >
> > > > gcc/testsuite/
> > > >
> > > > PR target/125355
> > > > * gcc.target/i386/pr125355.c: New test.
>
>
>
> --
> H.J.

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