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xtensa: Make use of CLAMPS instruction if configured

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This patch introduces the use of CLAMPS instruction when the instruction
is configured.

    /* example */
    int test(int a) {
      if (a < -512)
        return -512;
      if (a > 511)
        return 511;
      return a;
    }

    ;; prereq: TARGET_CLAMPS
    test:
	clamps	a2, a2, 9
	ret.n

gcc/ChangeLog:

	* config/xtensa/xtensa-protos.h (xtensa_match_CLAMPS_imms_p):
	New prototype.
	* config/xtensa/xtensa.cc (xtensa_match_CLAMPS_imms_p):
	New function.
	* config/xtensa/xtensa.h (TARGET_CLAMPS): New macro definition.
	* config/xtensa/xtensa.md (*xtensa_clamps): New insn pattern.
This commit is contained in:
Takayuki 'January June' Suwa 2023-02-27 02:27:42 +09:00 • committed by Max Filippov
parent 999b7aab21
commit ce83c3e492
4 changed files with 52 additions and 0 deletions
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1
gcc/config/xtensa/xtensa-protos.h
View file

@ -60,6 +60,7 @@ 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 *);
extern bool xtensa_match_CLAMPS_imms_p (rtx, rtx);
#ifdef TREE_CODE
extern void init_cumulative_args (CUMULATIVE_ARGS *, int);

13
gcc/config/xtensa/xtensa.cc
View file

@ -2611,6 +2611,19 @@ xtensa_emit_add_imm (rtx dst, rtx src, HOST_WIDE_INT imm, rtx scratch,
}
/* Return true if the constants used in the application of smin() following
smax() meet the specifications of the CLAMPS machine instruction. */
bool
xtensa_match_CLAMPS_imms_p (rtx cst_max, rtx cst_min)
{
int max, min;
return IN_RANGE (max = exact_log2 (-INTVAL (cst_max)), 7, 22)
&& IN_RANGE (min = exact_log2 (INTVAL (cst_min) + 1), 7, 22)
&& max == min;
}
/* Implement TARGET_CANNOT_FORCE_CONST_MEM. */
static bool

1
gcc/config/xtensa/xtensa.h
View file

@ -35,6 +35,7 @@ along with GCC; see the file COPYING3. If not see
#define TARGET_NSA XCHAL_HAVE_NSA
#define TARGET_MINMAX XCHAL_HAVE_MINMAX
#define TARGET_SEXT XCHAL_HAVE_SEXT
#define TARGET_CLAMPS XCHAL_HAVE_CLAMPS
#define TARGET_BOOLEANS XCHAL_HAVE_BOOLEANS
#define TARGET_HARD_FLOAT XCHAL_HAVE_FP
#define TARGET_HARD_FLOAT_DIV XCHAL_HAVE_FP_DIV

37
gcc/config/xtensa/xtensa.md
View file

@ -446,6 +446,43 @@
(set_attr "mode" "SI")
(set_attr "length" "3")])
;; Signed clamp.
(define_insn_and_split "*xtensa_clamps"
[(set (match_operand:SI 0 "register_operand" "=a")
(smax:SI (smin:SI (match_operand:SI 1 "register_operand" "r")
(match_operand:SI 2 "const_int_operand" "i"))
(match_operand:SI 3 "const_int_operand" "i")))]
"TARGET_CLAMPS
&& xtensa_match_CLAMPS_imms_p (operands[3], operands[2])"
"#"
"&& 1"
[(set (match_dup 0)
(smin:SI (smax:SI (match_dup 1)
(match_dup 3))
(match_dup 2)))]
""
[(set_attr "type" "arith")
(set_attr "mode" "SI")
(set_attr "length" "3")])
(define_insn "*xtensa_clamps"
[(set (match_operand:SI 0 "register_operand" "=a")
(smin:SI (smax:SI (match_operand:SI 1 "register_operand" "r")
(match_operand:SI 2 "const_int_operand" "i"))
(match_operand:SI 3 "const_int_operand" "i")))]
"TARGET_CLAMPS
&& xtensa_match_CLAMPS_imms_p (operands[2], operands[3])"
{
static char result[64];
sprintf (result, "clamps\t%%0, %%1, %d", floor_log2 (-INTVAL (operands[2])));
return result;
}
[(set_attr "type" "arith")
(set_attr "mode" "SI")
(set_attr "length" "3")])
;; Count redundant leading sign bits and leading/trailing zeros,
;; and find first bit.