Re: [PATCH v3] xtensa: Prepare the transition from Reload to LRA

[Jan-Benedict Glaw]

Hi!

On Wed, 2022-10-19 17:16:24 +0900, Takayuki 'January June' Suwa via Gcc-patches 
 wrote:
>   * gcc/config/xtensa/xtensa.md: Add two new split patterns:
> - splits DImode immediate load into two SImode ones
> - puts out-of-constraint SImode constants into the constant pool

> --- a/gcc/config/xtensa/xtensa.md
> +++ b/gcc/config/xtensa/xtensa.md
> @@ -940,14 +940,9 @@
>because of offering further optimization opportunities.  */
>if (register_operand (operands[0], DImode))
>   {
> -   rtx lowpart, highpart;
> -
> -   if (TARGET_BIG_ENDIAN)
> - split_double (operands[1], , );
> -   else
> - split_double (operands[1], , );
> -   emit_insn (gen_movsi (gen_lowpart (SImode, operands[0]), lowpart));
> -   emit_insn (gen_movsi (gen_highpart (SImode, operands[0]), highpart));
> +   xtensa_split_DI_reg_imm (operands);
> +   emit_move_insn (operands[0], operands[1]);
> +   emit_move_insn (operands[2], operands[3]);

This results in a new warning for me:

[all 2022-10-25 16:04:19] g++  -fno-PIE -c   -g -O2   -DIN_GCC  
-DCROSS_DIRECTORY_STRUCTURE   -fno-exceptions -fno-rtti 
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings 
-Wcast-qual -Wmissing-format-attribute -Woverloaded-virtual -pedantic 
-Wno-long-long -Wno-variadic-macros -Wno-overlength-strings -Werror -fno-common 
 -DHAVE_CONFIG_H -I. -I. -I../../gcc/gcc -I../../gcc/gcc/. 
-I../../gcc/gcc/../include -I../../gcc/gcc/../libcpp/include 
-I../../gcc/gcc/../libcody  -I../../gcc/gcc/../libdecnumber 
-I../../gcc/gcc/../libdecnumber/dpd -I../libdecnumber 
-I../../gcc/gcc/../libbacktrace   -o insn-emit.o -MT insn-emit.o -MMD -MP -MF 
./.deps/insn-emit.TPo insn-emit.cc
[all 2022-10-25 16:04:22] ../../gcc/gcc/config/xtensa/xtensa.md: In function 
'rtx_def* gen_movdi(rtx, rtx)':
[all 2022-10-25 16:04:22] ../../gcc/gcc/config/xtensa/xtensa.md:945:26: error: 
array subscript 3 is above array bounds of 'rtx_def* [2]' [-Werror=array-bounds]
[all 2022-10-25 16:04:22]   945 |   emit_move_insn (operands[2], 
operands[3]);
[all 2022-10-25 16:04:22]   |   
~~~^~
[all 2022-10-25 16:04:22] ../../gcc/gcc/config/xtensa/xtensa.md:897:9: note: 
while referencing 'operands'
[all 2022-10-25 16:04:22]   897 |(set_attr "mode" "SF")
[all 2022-10-25 16:04:22]   | ^~~~
[all 2022-10-25 16:04:22] ../../gcc/gcc/config/xtensa/xtensa.md:945:26: error: 
array subscript 2 is above array bounds of 'rtx_def* [2]' [-Werror=array-bounds]
[all 2022-10-25 16:04:22]   945 |   emit_move_insn (operands[2], 
operands[3]);
[all 2022-10-25 16:04:22]   |   
~~~^~
[all 2022-10-25 16:04:22] ../../gcc/gcc/config/xtensa/xtensa.md:897:9: note: 
while referencing 'operands'
[all 2022-10-25 16:04:22]   897 |(set_attr "mode" "SF")
[all 2022-10-25 16:04:22]   | ^~~~

I didn't yet actually check the warning, it may be bogus.

Thanks,
  Jan-Benedict

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Re: [PATCH v3] xtensa: Prepare the transition from Reload to LRA

[Max Filippov via Gcc-patches]

On Wed, Oct 19, 2022 at 1:16 AM Takayuki 'January June' Suwa
 wrote:
> This patch provides the first step in the transition from Reload to LRA
> in Xtensa.
>
> gcc/ChangeLog:
>
> * config/xtensa/xtensa-proto.h
> (xtensa_split1_finished_p, xtensa_split_DI_reg_imm): New prototypes.
> * config/xtensa/xtensa.cc
> (xtensa_split1_finished_p, xtensa_split_DI_reg_imm, xtensa_lra_p):
> New functions.
> (TARGET_LRA_P): Replace the dummy hook with xtensa_lra_p.
> (xt_true_regnum): Rework.
> * gcc/config/xtensa/xtensa.h (CALL_REALLY_USED_REGISTERS):
> Switch from CALL_USED_REGISTERS, and revise the comment.
> * gcc/config/xtensa/constraints.md (Y):
> Use !xtensa_split1_finished_p() instead of can_create_pseudo_p().
> * gcc/config/xtensa/predicates.md (move_operand): Ditto.
> * gcc/config/xtensa/xtensa.md: Add two new split patterns:
>   - splits DImode immediate load into two SImode ones
>   - puts out-of-constraint SImode constants into the constant pool
> * gcc/config/xtensa/xtensa.opt (-mlra): New target-specific option
> for testing purpose.
> ---
>  gcc/config/xtensa/constraints.md  |  2 +-
>  gcc/config/xtensa/predicates.md   |  2 +-
>  gcc/config/xtensa/xtensa-protos.h |  2 +
>  gcc/config/xtensa/xtensa.cc   | 69 ++-
>  gcc/config/xtensa/xtensa.h|  8 ++--
>  gcc/config/xtensa/xtensa.md   | 36 
>  gcc/config/xtensa/xtensa.opt  |  4 ++
>  7 files changed, 99 insertions(+), 24 deletions(-)

Regtested for target=xtensa-linux-uclibc, no new regressions.
Committed to master after fixing the changelog.

-- 
Thanks.
-- Max