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Re: [PATCH,ARM][4/n] Add negdi_extend patterns
- From: Ramana Radhakrishnan <ramana dot gcc at googlemail dot com>
- To: Greta Yorsh <greta dot yorsh at arm dot com>
- Cc: GCC Patches <gcc-patches at gcc dot gnu dot org>, Richard Earnshaw <Richard dot Earnshaw at arm dot com>, Ramana Radhakrishnan <Ramana dot Radhakrishnan at arm dot com>, nickc at redhat dot com, paul at codesourcery dot com
- Date: Tue, 26 Mar 2013 13:36:48 +0000
- Subject: Re: [PATCH,ARM][4/n] Add negdi_extend patterns
- References: <512275db dot 4755420a dot 4699 dot 59dcSMTPIN_ADDED_BROKEN at mx dot google dot com>
- Reply-to: ramrad01 at arm dot com
On Mon, Feb 18, 2013 at 6:40 PM, Greta Yorsh <greta.yorsh@arm.com> wrote:
> This patch adds patterns to handle negation of an extended 32-bit value more
> efficiently.
>
> For example,
>
> (set (reg:DI r0) (neg:DI (sign_extend:DI (reg:SI r0)))
>
> The compiler currently generates
> mov r1, r0, asr #31
> rsbs r0, r0, #0
> rsc r1, r1, #0
> and after the patch it generates:
> rsb r0, r0, #0
> mov r1, r0, asr #31
>
> (set (reg:DI r0) (neg:DI (zero_extend:DI (reg:SI r0)))
>
> The compiler currently generates
> mov r1, #0
> rsbs r0, r0, #0
> rsc r1, r1, #0
> and after the patch it generates:
> rsbs r0, r0, #0
> sbc r1, r1, r1
>
> The following examples are not affected by the patch:
>
> (set (reg:DI r0) (sign_extend:DI (neg:SI (reg:SI r0)))
> rsb r0, r0, #0
> mov r1, r0, asr #31
>
> (set (reg:DI r0) (zero_extend:DI (neg:SI (reg:SI r0)))
> rsb r0, r0, #0
> mov r1, #0
>
> The patch also adds the appropriate test cases.
>
> gcc/
>
> 2013-01-10 Greta Yorsh <Greta.Yorsh@arm.com>
>
> * config/arm/arm.md (negdi_extendsidi): New pattern.
> (negdi_zero_extendsidi): Likewise.
>
> gcc/testsuite
>
> 2013-01-10 Greta Yorsh <Greta.Yorsh@arm.com>
>
> * gcc.target/arm/negdi-1.c: New test.
> * gcc.target/arm/negdi-2.c: Likewise.
> * gcc.target/arm/negdi-3.c: Likewise.
> * gcc.target/arm/negdi-4.c: Likewise.
Ok.
Ramana