Update x86-tune-costs.h for znver2

[Jan Hubicka]

> Hi,
> this patch updates znver2 costs to match reality.  In particular we
> re-benchmarked memcpy strategies and it looks that glibc now wins even
> for relatively small blocks. 
> Moreover I updated costs of moves to reflect that znver2 has 256 vector
> paths and faster multiplication.
> 
> Bootstrapped/regtested x86_64-linux, comitted.
> 
> Honza
> 
> 	* x86-tune-costs.h (znver2_memcpy): Update.
> 	(znver2_costs): Update 256 bit SSE costs and multiplication.

Hello,
I have now backported the patch to gcc 9 branch.

Honza
> Index: config/i386/x86-tune-costs.h
> ===================================================================
> --- config/i386/x86-tune-costs.h	(revision 273727)
> +++ config/i386/x86-tune-costs.h	(working copy)
> @@ -1279,12 +1279,12 @@ struct processor_costs znver1_cost = {
>  static stringop_algs znver2_memcpy[2] = {
>    {libcall, {{6, loop, false}, {14, unrolled_loop, false},
>  	     {-1, rep_prefix_4_byte, false}}},
> -  {libcall, {{16, loop, false}, {8192, rep_prefix_8_byte, false},
> +  {libcall, {{16, loop, false}, {64, rep_prefix_4_byte, false},
>  	     {-1, libcall, false}}}};
>  static stringop_algs znver2_memset[2] = {
>    {libcall, {{8, loop, false}, {24, unrolled_loop, false},
>  	     {2048, rep_prefix_4_byte, false}, {-1, libcall, false}}},
> -  {libcall, {{48, unrolled_loop, false}, {8192, rep_prefix_8_byte, false},
> +  {libcall, {{24, rep_prefix_4_byte, false}, {128, rep_prefix_8_byte, false},
>  	     {-1, libcall, false}}}};
>  
>  struct processor_costs znver2_cost = {
> @@ -1335,11 +1335,11 @@ struct processor_costs znver2_cost = {
>  					   in SImode and DImode.  */
>    {8, 8},				/* cost of storing MMX registers
>  					   in SImode and DImode.  */
> -  2, 3, 6,				/* cost of moving XMM,YMM,ZMM
> +  2, 2, 3,				/* cost of moving XMM,YMM,ZMM
>  					   register.  */
> -  {6, 6, 6, 10, 20},			/* cost of loading SSE registers
> +  {6, 6, 6, 6, 12},			/* cost of loading SSE registers
>  					   in 32,64,128,256 and 512-bit.  */
> -  {6, 6, 6, 10, 20},			/* cost of unaligned loads.  */
> +  {6, 6, 6, 6, 12},			/* cost of unaligned loads.  */
>    {8, 8, 8, 8, 16},			/* cost of storing SSE registers
>  					   in 32,64,128,256 and 512-bit.  */
>    {8, 8, 8, 8, 16},			/* cost of unaligned stores.  */
> @@ -1372,7 +1372,7 @@ struct processor_costs znver2_cost = {
>    COSTS_N_INSNS (1),			/* cost of cheap SSE instruction.  */
>    COSTS_N_INSNS (3),			/* cost of ADDSS/SD SUBSS/SD insns.  */
>    COSTS_N_INSNS (3),			/* cost of MULSS instruction.  */
> -  COSTS_N_INSNS (4),			/* cost of MULSD instruction.  */
> +  COSTS_N_INSNS (3),			/* cost of MULSD instruction.  */
>    COSTS_N_INSNS (5),			/* cost of FMA SS instruction.  */
>    COSTS_N_INSNS (5),			/* cost of FMA SD instruction.  */
>    COSTS_N_INSNS (10),			/* cost of DIVSS instruction.  */