[v3] xtensa: Prepare the transition from Reload to LRA
Checks
Commit Message
On 2022/10/18 21:16, Max Filippov wrote:
> Hi Suwa-san,
Hi!
> I've noticed that this is related to the following hunk:
>
> -#define CALL_USED_REGISTERS \
> +#define CALL_REALLY_USED_REGISTERS \
> { \
> - 1, 1, 4, 4, 4, 4, 4, 4, 1, 1, 1, 1, 2, 2, 2, 2, \
> - 1, 1, 1, \
> + 0, 0, 4, 4, 4, 4, 4, 4, 1, 1, 1, 1, 2, 2, 2, 2, \
> + 0, 0, 1, \
> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \
> 1, \
> }
>
> And the following change on top of v2 fixes this regression for me:
>
> diff --git a/gcc/config/xtensa/xtensa.h b/gcc/config/xtensa/xtensa.h
> index 6b60e5960625..897f87f735da 100644
> --- a/gcc/config/xtensa/xtensa.h
> +++ b/gcc/config/xtensa/xtensa.h
> @@ -244,7 +244,7 @@ along with GCC; see the file COPYING3. If not see
>
> #define CALL_REALLY_USED_REGISTERS \
> { \
> - 0, 0, 4, 4, 4, 4, 4, 4, 1, 1, 1, 1, 2, 2, 2, 2, \
> + 1, 0, 4, 4, 4, 4, 4, 4, 1, 1, 1, 1, 2, 2, 2, 2, \
> 0, 0, 1, \
> 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \
> 1, \
If we take "CALL_REALLY_USED_REGISTERS" literally, it makes sense because the CALL0/CALLX0 instructions actually change the A0 register.
(little question: Then FIXED_REGISTERS is interpreted as not including the link register, but is that correct...)
===
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(-)
Comments
On Wed, Oct 19, 2022 at 1:16 AM Takayuki 'January June' Suwa
<jjsuwa_sys3175@yahoo.co.jp> 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.
Hi!
On Wed, 2022-10-19 17:16:24 +0900, Takayuki 'January June' Suwa via Gcc-patches <gcc-patches@gcc.gnu.org> 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], &highpart, &lowpart);
> - else
> - split_double (operands[1], &lowpart, &highpart);
> - 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
--
On 2022/10/26 5:09, Jan-Benedict Glaw wrote:
> Hi!
Hi!
> 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 for your report. I'm aware of that warning.
@@ -121,7 +121,7 @@
(ior (and (match_code "const_int,const_double,const,symbol_ref,label_ref")
(match_test "TARGET_AUTO_LITPOOLS"))
(and (match_code "const_int")
- (match_test "can_create_pseudo_p ()"))))
+ (match_test "! xtensa_split1_finished_p ()"))))
;; Memory constraints. Do not use define_memory_constraint here. Doing so
;; causes reload to force some constants into the constant pool, but since
@@ -149,7 +149,7 @@
(ior (and (match_code "const_int")
(match_test "(GET_MODE_CLASS (mode) == MODE_INT
&& xtensa_simm12b (INTVAL (op)))
- || can_create_pseudo_p ()"))
+ || ! xtensa_split1_finished_p ()"))
(and (match_code "const_int,const_double,const,symbol_ref,label_ref")
(match_test "(TARGET_CONST16 || TARGET_AUTO_LITPOOLS)
&& CONSTANT_P (op)
@@ -58,6 +58,8 @@ extern char *xtensa_emit_call (int, rtx *);
extern char *xtensa_emit_sibcall (int, rtx *);
extern bool xtensa_tls_referenced_p (rtx);
extern enum rtx_code xtensa_shlrd_which_direction (rtx, rtx);
+extern bool xtensa_split1_finished_p (void);
+extern void xtensa_split_DI_reg_imm (rtx *);
#ifdef TREE_CODE
extern void init_cumulative_args (CUMULATIVE_ARGS *, int);
@@ -56,6 +56,7 @@ along with GCC; see the file COPYING3. If not see
#include "hw-doloop.h"
#include "rtl-iter.h"
#include "insn-attr.h"
+#include "tree-pass.h"
/* This file should be included last. */
#include "target-def.h"
@@ -199,6 +200,7 @@ static void xtensa_output_mi_thunk (FILE *file, tree thunk ATTRIBUTE_UNUSED,
HOST_WIDE_INT delta,
HOST_WIDE_INT vcall_offset,
tree function);
+static bool xtensa_lra_p (void);
static rtx xtensa_delegitimize_address (rtx);
@@ -295,7 +297,7 @@ static rtx xtensa_delegitimize_address (rtx);
#define TARGET_CANNOT_FORCE_CONST_MEM xtensa_cannot_force_const_mem
#undef TARGET_LRA_P
-#define TARGET_LRA_P hook_bool_void_false
+#define TARGET_LRA_P xtensa_lra_p
#undef TARGET_LEGITIMATE_ADDRESS_P
#define TARGET_LEGITIMATE_ADDRESS_P xtensa_legitimate_address_p
@@ -492,21 +494,30 @@ xtensa_mask_immediate (HOST_WIDE_INT v)
int
xt_true_regnum (rtx x)
{
- if (GET_CODE (x) == REG)
+ if (REG_P (x))
{
- if (reg_renumber
- && REGNO (x) >= FIRST_PSEUDO_REGISTER
- && reg_renumber[REGNO (x)] >= 0)
+ if (! HARD_REGISTER_P (x)
+ && reg_renumber
+ && (lra_in_progress || reg_renumber[REGNO (x)] >= 0))
return reg_renumber[REGNO (x)];
return REGNO (x);
}
- if (GET_CODE (x) == SUBREG)
+ if (SUBREG_P (x))
{
int base = xt_true_regnum (SUBREG_REG (x));
- if (base >= 0 && base < FIRST_PSEUDO_REGISTER)
- return base + subreg_regno_offset (REGNO (SUBREG_REG (x)),
- GET_MODE (SUBREG_REG (x)),
- SUBREG_BYTE (x), GET_MODE (x));
+
+ if (base >= 0
+ && HARD_REGISTER_NUM_P (base))
+ {
+ struct subreg_info info;
+
+ subreg_get_info (lra_in_progress
+ ? (unsigned) base : REGNO (SUBREG_REG (x)),
+ GET_MODE (SUBREG_REG (x)),
+ SUBREG_BYTE (x), GET_MODE (x), &info);
+ if (info.representable_p)
+ return base + info.offset;
+ }
}
return -1;
}
@@ -2477,6 +2488,36 @@ xtensa_shlrd_which_direction (rtx op0, rtx op1)
}
+/* Return true after "split1" pass has been finished. */
+
+bool
+xtensa_split1_finished_p (void)
+{
+ return cfun && (cfun->curr_properties & PROP_rtl_split_insns);
+}
+
+
+/* Split a DImode pair of reg (operand[0]) and const_int (operand[1]) into
+ two SImode pairs, the low-part (operands[0] and [1]) and the high-part
+ (operands[2] and [3]). */
+
+void
+xtensa_split_DI_reg_imm (rtx *operands)
+{
+ rtx lowpart, highpart;
+
+ if (WORDS_BIG_ENDIAN)
+ split_double (operands[1], &highpart, &lowpart);
+ else
+ split_double (operands[1], &lowpart, &highpart);
+
+ operands[3] = highpart;
+ operands[2] = gen_highpart (SImode, operands[0]);
+ operands[1] = lowpart;
+ operands[0] = gen_lowpart (SImode, operands[0]);
+}
+
+
/* Implement TARGET_CANNOT_FORCE_CONST_MEM. */
static bool
@@ -5119,4 +5160,12 @@ xtensa_delegitimize_address (rtx op)
return op;
}
+/* Implement TARGET_LRA_P. */
+
+static bool
+xtensa_lra_p (void)
+{
+ return TARGET_LRA;
+}
+
#include "gt-xtensa.h"
@@ -229,7 +229,7 @@ along with GCC; see the file COPYING3. If not see
}
/* 1 for registers not available across function calls.
- These must include the FIXED_REGISTERS and also any
+ These need not include the FIXED_REGISTERS but must any
registers that can be used without being saved.
The latter must include the registers where values are returned
and the register where structure-value addresses are passed.
@@ -242,10 +242,10 @@ along with GCC; see the file COPYING3. If not see
Proper values are computed in TARGET_CONDITIONAL_REGISTER_USAGE. */
-#define CALL_USED_REGISTERS \
+#define CALL_REALLY_USED_REGISTERS \
{ \
- 1, 1, 4, 4, 4, 4, 4, 4, 1, 1, 1, 1, 2, 2, 2, 2, \
- 1, 1, 1, \
+ 1, 0, 4, 4, 4, 4, 4, 4, 1, 1, 1, 1, 2, 2, 2, 2, \
+ 0, 0, 1, \
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \
1, \
}
@@ -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], &highpart, &lowpart);
- else
- split_double (operands[1], &lowpart, &highpart);
- 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]);
DONE;
}
@@ -981,6 +976,19 @@
}
})
+(define_split
+ [(set (match_operand:DI 0 "register_operand")
+ (match_operand:DI 1 "const_int_operand"))]
+ "!TARGET_CONST16 && !TARGET_AUTO_LITPOOLS
+ && ! xtensa_split1_finished_p ()"
+ [(set (match_dup 0)
+ (match_dup 1))
+ (set (match_dup 2)
+ (match_dup 3))]
+{
+ xtensa_split_DI_reg_imm (operands);
+})
+
;; 32-bit Integer moves
(define_expand "movsi"
@@ -1017,6 +1025,18 @@
(set_attr "mode" "SI")
(set_attr "length" "2,2,2,2,2,2,3,3,3,3,6,3,3,3,3,3")])
+(define_split
+ [(set (match_operand:SI 0 "register_operand")
+ (match_operand:SI 1 "const_int_operand"))]
+ "!TARGET_CONST16 && !TARGET_AUTO_LITPOOLS
+ && ! xtensa_split1_finished_p ()
+ && ! xtensa_simm12b (INTVAL (operands[1]))"
+ [(set (match_dup 0)
+ (match_dup 1))]
+{
+ operands[1] = force_const_mem (SImode, operands[1]);
+})
+
(define_split
[(set (match_operand:SI 0 "register_operand")
(match_operand:SI 1 "constantpool_operand"))]
@@ -34,6 +34,10 @@ mextra-l32r-costs=
Target RejectNegative Joined UInteger Var(xtensa_extra_l32r_costs) Init(0)
Set extra memory access cost for L32R instruction, in clock-cycle units.
+mlra
+Target Mask(LRA)
+Use LRA instead of reload (transitional).
+
mtarget-align
Target
Automatically align branch targets to reduce branch penalties.