Re: [PATCH][AArch64] Improve address cost for -mcpu=generic

[Richard Earnshaw (lists)]

On 12/04/17 14:08, Wilco Dijkstra wrote:
> All cores which add a cpu_addrcost_table use a non-zero value for
> HI and TI mode shifts (a non-zero value for general indexing also 
> applies to all shifts).  Given this, it makes no sense to use a
> different setting in generic_addrcost_table.  So change it so that all
> supported cores, including -mcpu=generic, now generate the same:
> 

That's not quite true: exynosm1_addrcost_table has 0 for HI but 2 for
TI; though use of TI here is a bit misleading as it essentially means
"any scaling that isn't 2, 4 or 8".

That being said, this change does seem to be closer to the more general
trend; furthermore, single scaled-offset mems are still merged into one
instruction.

OK.

R.

> int f(short *p, short *q, long x) { return p[x] + q[x]; }
> 
>   lsl x2, x2, 1
>   ldrsh   w3, [x0, x2]
>   ldrsh   w0, [x1, x2]
>   add w0, w3, w0
>   ret
> 
> Bootstrapped for AArch64. Any comments? OK for stage 1?
> 
> ChangeLog:
> 2017-04-12  Wilco Dijkstra  
> 
> * gcc/config/aarch64/aarch64.c (generic_addrcost_table):
> Change HI/TI mode setting.
> 
> ---
> diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
> index 
> 419b756efcb40e48880cd4529efc4f9f59938325..728ce7029f1e2b5161d9f317d10e564dd5a5f472
>  100644
> --- a/gcc/config/aarch64/aarch64.c
> +++ b/gcc/config/aarch64/aarch64.c
> @@ -193,10 +193,10 @@ static const struct aarch64_flag_desc 
> aarch64_tuning_flags[] =
>  static const struct cpu_addrcost_table generic_addrcost_table =
>  {
>  {
> -  0, /* hi  */
> +  1, /* hi  */
>0, /* si  */
>0, /* di  */
> -  0, /* ti  */
> +  1, /* ti  */
>  },
>0, /* pre_modify  */
>0, /* post_modify  */
> 

Re: [PATCH][AArch64] Improve address cost for -mcpu=generic

[Wilco Dijkstra]

ping

From: Wilco Dijkstra
Sent: 12 April 2017 14:08
To: GCC Patches
Cc: nd; James Greenhalgh; Evandro Menezes; jim.wil...@linaro.org; 
andrew.pin...@cavium.com
Subject: [PATCH][AArch64] Improve address cost for -mcpu=generic
    
All cores which add a cpu_addrcost_table use a non-zero value for
HI and TI mode shifts (a non-zero value for general indexing also 
applies to all shifts).  Given this, it makes no sense to use a
different setting in generic_addrcost_table.  So change it so that all
supported cores, including -mcpu=generic, now generate the same:

int f(short *p, short *q, long x) { return p[x] + q[x]; }

    lsl x2, x2, 1
    ldrsh   w3, [x0, x2]
    ldrsh   w0, [x1, x2]
    add w0, w3, w0
    ret

Bootstrapped for AArch64. Any comments? OK for stage 1?

ChangeLog:
2017-04-12  Wilco Dijkstra  

    * gcc/config/aarch64/aarch64.c (generic_addrcost_table):
    Change HI/TI mode setting.

---
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 
419b756efcb40e48880cd4529efc4f9f59938325..728ce7029f1e2b5161d9f317d10e564dd5a5f472
 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -193,10 +193,10 @@ static const struct aarch64_flag_desc 
aarch64_tuning_flags[] =
 static const struct cpu_addrcost_table generic_addrcost_table =
 {
 {
-  0, /* hi  */
+  1, /* hi  */
   0, /* si  */
   0, /* di  */
-  0, /* ti  */
+  1, /* ti  */
 },
   0, /* pre_modify  */
   0, /* post_modify  */

[PATCH][AArch64] Improve address cost for -mcpu=generic

[Wilco Dijkstra]

All cores which add a cpu_addrcost_table use a non-zero value for
HI and TI mode shifts (a non-zero value for general indexing also 
applies to all shifts).  Given this, it makes no sense to use a
different setting in generic_addrcost_table.  So change it so that all
supported cores, including -mcpu=generic, now generate the same:

int f(short *p, short *q, long x) { return p[x] + q[x]; }

lsl x2, x2, 1
ldrsh   w3, [x0, x2]
ldrsh   w0, [x1, x2]
add w0, w3, w0
ret

Bootstrapped for AArch64. Any comments? OK for stage 1?

ChangeLog:
2017-04-12  Wilco Dijkstra  

* gcc/config/aarch64/aarch64.c (generic_addrcost_table):
Change HI/TI mode setting.

---
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index 
419b756efcb40e48880cd4529efc4f9f59938325..728ce7029f1e2b5161d9f317d10e564dd5a5f472
 100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -193,10 +193,10 @@ static const struct aarch64_flag_desc 
aarch64_tuning_flags[] =
 static const struct cpu_addrcost_table generic_addrcost_table =
 {
 {
-  0, /* hi  */
+  1, /* hi  */
   0, /* si  */
   0, /* di  */
-  0, /* ti  */
+  1, /* ti  */
 },
   0, /* pre_modify  */
   0, /* post_modify  */