Hi Andrea,
Sorry for the delay
> -----Original Message-----
> From: Gcc-patches <gcc-patches-boun...@gcc.gnu.org> On Behalf Of
> Andrea Corallo
> Sent: 24 June 2020 11:04
> To: gcc-patches@gcc.gnu.org
> Cc: Richard Earnshaw <richard.earns...@arm.com>; nd <n...@arm.com>;
> Kyrill Tkachov <kyrylo.tkac...@foss.arm.com>
> Subject: Re: [PATCH v4] arm: Implement Armv8.1-M low overhead loops
>
> Andrea Corallo <andrea.cora...@arm.com> writes:
>
> > Hi all,
> >
> > here the latest version of the patch to enable Armv8.1-M Mainline
> > LOB (low overhead branch) extension low overhead loops (LOL) feature
> > using the 'loop-doloop' pass.
> >
> > I posted a previous version of it during stage 4.
> >
> > Given the following function:
> >
> > void
> > loop (int *a)
> > {
> > for (int i = 0; i < 1000; i++)
> > a[i] = i;
> > }
> >
> > 'doloop_begin' and 'doloop_end' patterns translates into 'dls' and 'le'
> > giving:
> >
> > loop:
> > movw r2, #10000
> > movs r3, #0
> > subs r0, r0, #4
> > push {lr}
> > dls lr, r2
> > .L2:
> > str r3, [r0, #4]!
> > adds r3, r3, #1
> > le lr, .L2
> > ldr pc, [sp], #4
> >
> > bootstrapped arm-none-linux-gnueabihf, does not introduce testsuite
> regressions.
> >
> > Andrea
>
> Hi,
>
> double checking I spotted another test impacted by the patch that I
> missed as first.
>
> Here the updated patch waving the check.
>
> Andrea
>
> gcc/ChangeLog
>
> 2020-06-18 Andrea Corallo <andrea.cora...@arm.com>
> Mihail-Calin Ionescu <mihail.ione...@arm.com>
> Iain Apreotesei <iain.apreote...@arm.com>
>
> * config/arm/arm-protos.h (arm_target_insn_ok_for_lob): New
> prototype.
> * config/arm/arm.c (TARGET_INVALID_WITHIN_DOLOOP): Define.
> (arm_invalid_within_doloop): Implement invalid_within_doloop hook.
> (arm_target_insn_ok_for_lob): New function.
> * config/arm/arm.h (TARGET_HAVE_LOB): Define macro.
> * config/arm/thumb2.md (*doloop_end_internal, doloop_begin)
> (dls_insn): Add new patterns.
> (doloop_end): Modify to select LR when LOB is available.
> * config/arm/unspecs.md: Add new unspec.
> * doc/sourcebuild.texi (arm_v8_1_lob_ok)
> (arm_thumb2_ok_no_arm_v8_1_lob): Document new target
> supports
> options.
>
> gcc/testsuite/ChangeLog
>
> 2020-06-18 Andrea Corallo <andrea.cora...@arm.com>
> Mihail-Calin Ionescu <mihail.ione...@arm.com>
> Iain Apreotesei <iain.apreote...@arm.com>
>
> * gcc.target/arm/lob.h: New header.
> * gcc.target/arm/lob1.c: New testcase.
> * gcc.target/arm/lob2.c: Likewise.
> * gcc.target/arm/lob3.c: Likewise.
> * gcc.target/arm/lob4.c: Likewise.
> * gcc.target/arm/lob5.c: Likewise.
> * gcc.target/arm/lob6.c: Likewise.
> * gcc.target/arm/unsigned-extend-2.c: Do not run when generating
> low loop overhead.
> * gcc.target/arm/ivopts.c: Fix check for low loop overhead.
> * lib/target-supports.exp (check_effective_target_arm_v8_1_lob)
> (check_effective_target_arm_thumb2_ok_no_arm_v8_1_lob): New
> procs.
Ok.
Thanks for doing this.
Kyrill
