[PATCH][ARM] Improve code generation for anddi3

[Kyrylo Tkachov]

Ping?

Thanks,
Kyrill

> -----Original Message-----
> From: gcc-patches-owner@gcc.gnu.org [mailto:gcc-patches-
> owner@gcc.gnu.org] On Behalf Of Kyrylo Tkachov
> Sent: 08 April 2013 13:47
> To: gcc-patches@gcc.gnu.org
> Cc: Ramana Radhakrishnan; Richard Earnshaw
> Subject: [PATCH][ARM] Improve code generation for anddi3
> 
> Hi all,
> 
> When compiling:
> 
> unsigned long long
> muld (unsigned long long X, unsigned long long Y)
> {
>   unsigned long long mask = 0xffffffffull;
>   return (X & mask) * (Y & mask);
> }
> 
> we get a suboptimal sequence:
>         stmfd   sp!, {r4, r5}
>         mvn     r4, #0
>         mov     r5, #0
>         and     r0, r0, r4
>         and     r3, r3, r5
>         and     r1, r1, r5
>         and     r2, r2, r4
>         mul     r3, r0, r3
>         mla     r3, r2, r1, r3
>         umull   r0, r1, r0, r2
>         ldmfd   sp!, {r4, r5}
>         add     r1, r3, r1
>         bx      lr
> 
> This patch improves that situation by changing the anddi3 insn into an
> insn_and_split and
> simplifying the SImode ands. Also, the NEON version is merged with the
> non-NEON one.
> This allows us to generate just:
>         umull   r0, r1, r2, r0
>         bx      lr
> for the above code.
> 
> Regtested arm-none-eabi on qemu.
> Ok for trunk?
> 
> Thanks,
> Kyrill
> 
> 
> gcc/ChangeLog
> 2013-04-08  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
> 
>         * config/arm/arm.c (const_ok_for_dimode_op): Handle AND case.
>         * config/arm/arm.md (*anddi3_insn): Change to insn_and_split.
>         * config/arm/constraints.md (De): New constraint.
>         * config/arm/neon.md (anddi3_neon): Delete.
>         (neon_vand<mode>): Expand to standard anddi3 pattern.
>         * config/arm/predicates.md (imm_for_neon_inv_logic_operand):
>         Move earlier in the file.
>         (neon_inv_logic_op2): Likewise.
>         (arm_anddi_operand_neon): New predicate.
> 
> gcc/testsuite/ChangeLog
> 2013-04-08  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
> 
>         * gcc.target/arm/anddi3-opt.c: New test.
>         * gcc.target/arm/anddi3-opt2.c: Likewise.