[gcc r12-1015] AArch64: Enable fast shifts on Neoverse N1

[gcc r12-1015] AArch64: Enable fast shifts on Neoverse N1

[Wilco Dijkstra]

https://gcc.gnu.org/g:b326f495218a213079f572bd9960903b3425da74

commit r12-1015-gb326f495218a213079f572bd9960903b3425da74
Author: Wilco Dijkstra <wdijkstr@arm.com>
Date:   Mon May 24 14:31:37 2021 +0100

    AArch64: Enable fast shifts on Neoverse N1
    
    Enable the fast shift feature in Neoverse N1 tuning - this means additions with
    a shift left by 1-4 are as fast as addition. This improves multiply by constant
    expansions, eg. x * 25 is now emitted using shifts rather than a multiply:
    
    add w0, w0, w0, lsl 2
    add w0, w0, w0, lsl 2
    
    ChangeLog:
    2020-09-11  Wilco Dijkstra  <wdijkstr@arm.com>
    
            * config/aarch64/aarch64.c (neoversen1_tunings):
            Enable AARCH64_EXTRA_TUNE_CHEAP_SHIFT_EXTEND.

Diff:
---
 gcc/config/aarch64/aarch64.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index e9f961d41fa..2753c852abd 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -1659,7 +1659,7 @@ static const struct tune_params neoversen1_tunings =
   2,	/* min_div_recip_mul_df.  */
   0,	/* max_case_values.  */
   tune_params::AUTOPREFETCHER_WEAK,	/* autoprefetcher_model.  */
-  (AARCH64_EXTRA_TUNE_NONE),	/* tune_flags.  */
+  (AARCH64_EXTRA_TUNE_CHEAP_SHIFT_EXTEND),	/* tune_flags.  */
   &generic_prefetch_tune
 };