Hi Roger,
Indeed, I was missing the patch file.
Approved.
Thank you for your contribution,
Claudiu
On Sun, Oct 15, 2023 at 11:14 AM Roger Sayle <ro...@nextmovesoftware.com> wrote:
>
> I’ve done it again. ENOPATCH.
>
>
>
> From: Roger Sayle <ro...@nextmovesoftware.com>
> Sent: 15 October 2023 09:13
> To: 'gcc-patches@gcc.gnu.org' <gcc-patches@gcc.gnu.org>
> Cc: 'Claudiu Zissulescu' <claz...@gmail.com>
> Subject: [ARC PATCH] Split asl dst,1,src into bset dst,0,src to implement
> 1<<x.
>
>
>
>
>
> This patch adds a pre-reload splitter to arc.md, to use the bset (set
>
> specific bit instruction) to implement 1<<x (i.e. left shifts of one)
>
> on ARC processors that don't have a barrel shifter.
>
>
>
> Currently,
>
>
>
> int foo(int x) {
>
> return 1 << x;
>
> }
>
>
>
> when compiled with -O2 -mcpu=em is compiled as a loop:
>
>
>
> foo: mov_s r2,1 ;3
>
> and.f lp_count,r0, 0x1f
>
> lpnz 2f
>
> add r2,r2,r2
>
> nop
>
> 2: # end single insn loop
>
> j_s.d [blink]
>
> mov_s r0,r2 ;4
>
>
>
> with this patch we instead generate a single instruction:
>
>
>
> foo: bset r0,0,r0
>
> j_s [blink]
>
>
>
>
>
> Finger-crossed this passes Claudiu's nightly testing. This patch
>
> has been minimally tested by building a cross-compiler cc1 to
>
> arc-linux hosted on x86_64-pc-linux-gnu with no additional failures
>
> seen with make -k check. Ok for mainline? Thanks in advance.
>
>
>
>
>
> 2023-10-15 Roger Sayle <ro...@nextmovesoftware.com>
>
>
>
> gcc/ChangeLog
>
> * config/arc/arc.md (*ashlsi3_1): New pre-reload splitter to
>
> use bset dst,0,src to implement 1<<x on !TARGET_BARREL_SHIFTER.
>
>
>
>
>
> Cheers,
>
> Roger
>
> --
>
>
