> -----Original Message-----
> From: Srinath Parvathaneni <srinath.parvathan...@arm.com>
> Sent: 15 June 2020 09:46
> To: gcc Patches <gcc-patches@gcc.gnu.org>
> Cc: Kyrylo Tkachov <kyrylo.tkac...@arm.com>; Richard Earnshaw
> <richard.earns...@arm.com>
> Subject: [PATCH][GCC] arm: Fix MVE scalar shift intrinsics code-gen.
>
> Hello,
>
> This patch modifies the MVE scalar shift RTL patterns. The current patterns
> have wrong constraints and predicates due to which the values returned
> from
> MVE scalar shift instructions are overwritten in the code-gen.
>
> example:
> $ cat x.c
> #include "arm_mve.h"
> int32_t foo(int64_t acc, int shift)
> {
> return sqrshrl_sat48 (acc, shift);
> }
>
> Code-gen before applying this patch:
> $ arm-none-eabi-gcc -march=armv8.1-m.main+mve -mfloat-abi=hard -O2 -S
> $ cat x.s
> foo:
> push {r4, r5}
> sqrshrl r0, r1, #48, r2 ----> (a)
> mov r0, r4 ----> (b)
> pop {r4, r5}
> bx lr
>
> Code-gen after applying this patch:
> foo:
> sqrshrl r0, r1, #48, r2
> bx lr
>
> In the current compiler the return value (r0) from sqrshrl (a) is getting
> overwritten by the mov statement (b).
> This patch fixes above issue.
>
> Please refer to M-profile Vector Extension (MVE) intrinsics [1]for more
> details.
> [1] https://developer.arm.com/architectures/instruction-sets/simd-
> isas/helium/mve-intrinsics
>
> Regression tested on arm-none-eabi and found no regressions.
>
> Ok for master and gcc-10 branch?
>
Ok.
Thanks,
Kyrill
> Thanks,
> Srinath.
>
> gcc/ChangeLog:
>
> 2020-06-12 Srinath Parvathaneni <srinath.parvathan...@arm.com>
>
> * config/arm/mve.md (mve_uqrshll_sat<supf>_di): Correct the predicate
> and constraint of all the operands.
> (mve_sqrshrl_sat<supf>_di): Likewise.
> (mve_uqrshl_si): Likewise.
> (mve_sqrshr_si): Likewise.
> (mve_uqshll_di): Likewise.
> (mve_urshrl_di): Likewise.
> (mve_uqshl_si): Likewise.
> (mve_urshr_si): Likewise.
> (mve_sqshl_si): Likewise.
> (mve_srshr_si): Likewise.
> (mve_srshrl_di): Likewise.
> (mve_sqshll_di): Likewise.
> * config/arm/predicates.md (arm_low_register_operand): Define.
>
> gcc/testsuite/ChangeLog:
>
> 2020-06-12 Srinath Parvathaneni <srinath.parvathan...@arm.com>
>
> * gcc.target/arm/mve/intrinsics/mve_scalar_shifts1.c: New test.
> * gcc.target/arm/mve/intrinsics/mve_scalar_shifts2.c: Likewise.
> * gcc.target/arm/mve/intrinsics/mve_scalar_shifts3.c: Likewise.
> * gcc.target/arm/mve/intrinsics/mve_scalar_shifts4.c: Likewise.
