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xtensa: Make complex hard register clobber elimination more robust and accurate

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This patch eliminates all clobbers for complex hard registers that will
be overwritten entirely afterwards (supersedence of
3867d414bd7d9e5b6fb2a51b1fb3d9e9e1eae9).

gcc/ChangeLog:

	* config/xtensa/xtensa.md: Rewrite the split pattern that performs
	the abovementioned process so that insns that overwrite clobbered
	register no longer need to be contiguous.
	(DSC): Remove as no longer needed.
This commit is contained in:
Takayuki 'January June' Suwa 2022-09-01 14:49:13 +09:00 • committed by Max Filippov
parent 06c2756e82
commit 89afb2e86f
1 changed files with 45 additions and 22 deletions
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67
gcc/config/xtensa/xtensa.md
View file

@ -86,10 +86,6 @@
;; This code iterator is for *shlrd and its variants.
(define_code_iterator ior_op [ior plus])
;; This mode iterator allows the DC and SC patterns to be defined from
;; the same template.
(define_mode_iterator DSC [DC SC])
;; Attributes.
@ -2843,27 +2839,54 @@
})
(define_split
[(clobber (match_operand:DSC 0 "register_operand"))]
"GP_REG_P (REGNO (operands[0]))"
[(clobber (match_operand 0 "register_operand"))]
"HARD_REGISTER_P (operands[0])
&& COMPLEX_MODE_P (GET_MODE (operands[0]))"
[(const_int 0)]
{
unsigned int regno = REGNO (operands[0]);
machine_mode inner_mode = GET_MODE_INNER (<MODE>mode);
auto_sbitmap bmp (FIRST_PSEUDO_REGISTER);
rtx_insn *insn;
rtx x;
if (! ((insn = next_nonnote_nondebug_insn (curr_insn))
&& NONJUMP_INSN_P (insn)
&& GET_CODE (x = PATTERN (insn)) == SET
&& REG_P (x = XEXP (x, 0))
&& GET_MODE (x) == inner_mode
&& REGNO (x) == regno
&& (insn = next_nonnote_nondebug_insn (insn))
&& NONJUMP_INSN_P (insn)
&& GET_CODE (x = PATTERN (insn)) == SET
&& REG_P (x = XEXP (x, 0))
&& GET_MODE (x) == inner_mode
&& REGNO (x) == regno + REG_NREGS (operands[0]) / 2))
FAIL;
rtx reg = gen_rtx_REG (SImode, 0);
bitmap_set_range (bmp, REGNO (operands[0]), REG_NREGS (operands[0]));
for (insn = next_nonnote_nondebug_insn_bb (curr_insn);
insn; insn = next_nonnote_nondebug_insn_bb (insn))
{
sbitmap_iterator iter;
unsigned int regno;
if (NONJUMP_INSN_P (insn))
{
EXECUTE_IF_SET_IN_BITMAP (bmp, 2, regno, iter)
{
set_regno_raw (reg, regno, REG_NREGS (reg));
if (reg_overlap_mentioned_p (reg, PATTERN (insn)))
break;
}
if (GET_CODE (PATTERN (insn)) == SET)
{
rtx x = SET_DEST (PATTERN (insn));
if (REG_P (x) && HARD_REGISTER_P (x))
bitmap_clear_range (bmp, REGNO (x), REG_NREGS (x));
else if (SUBREG_P (x) && HARD_REGISTER_P (SUBREG_REG (x)))
{
struct subreg_info info;
subreg_get_info (regno = REGNO (SUBREG_REG (x)),
GET_MODE (SUBREG_REG (x)),
SUBREG_BYTE (x), GET_MODE (x), &info);
if (!info.representable_p)
break;
bitmap_clear_range (bmp, regno + info.offset, info.nregs);
}
}
if (bitmap_empty_p (bmp))
goto FALLTHRU;
}
else if (CALL_P (insn))
EXECUTE_IF_SET_IN_BITMAP (bmp, 2, regno, iter)
if (call_used_or_fixed_reg_p (regno))
break;
}
FAIL;
FALLTHRU:;
})
(define_peephole2