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rtl-optimization/110587 - remove quadratic regno_in_use_p

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The following removes the code checking whether a noop copy
is between something involved in the return sequence composed
of a SET and USE.  Instead of checking for this special-case
the following makes us only ever remove noop copies between
pseudos - which is the case that is necessary for IRA/LRA
interfacing to function according to the comment.  That makes
looking for the return reg special case unnecessary, reducing
the compile-time in LRA non-specific to zero for the testcase.

	PR rtl-optimization/110587
	* lra-spills.cc (return_regno_p): Remove.
	(regno_in_use_p): Likewise.
	(lra_final_code_change): Do not remove noop moves
	between hard registers.
This commit is contained in:
Richard Biener 2023-07-25 15:32:11 +02:00
parent f0b7a61d83
commit 07b7cd7039
1 changed files with 1 additions and 68 deletions
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69
gcc/lra-spills.cc
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@ -705,72 +705,6 @@ alter_subregs (rtx *loc, bool final_p)
return res;
}
/* Return true if REGNO is used for return in the current
function. */
static bool
return_regno_p (unsigned int regno)
{
rtx outgoing = crtl->return_rtx;
if (! outgoing)
return false;
if (REG_P (outgoing))
return REGNO (outgoing) == regno;
else if (GET_CODE (outgoing) == PARALLEL)
{
int i;
for (i = 0; i < XVECLEN (outgoing, 0); i++)
{
rtx x = XEXP (XVECEXP (outgoing, 0, i), 0);
if (REG_P (x) && REGNO (x) == regno)
return true;
}
}
return false;
}
/* Return true if REGNO is in one of subsequent USE after INSN in the
same BB. */
static bool
regno_in_use_p (rtx_insn *insn, unsigned int regno)
{
static lra_insn_recog_data_t id;
static struct lra_static_insn_data *static_id;
struct lra_insn_reg *reg;
int i, arg_regno;
basic_block bb = BLOCK_FOR_INSN (insn);
while ((insn = next_nondebug_insn (insn)) != NULL_RTX)
{
if (BARRIER_P (insn) || bb != BLOCK_FOR_INSN (insn))
return false;
if (! INSN_P (insn))
continue;
if (GET_CODE (PATTERN (insn)) == USE
&& REG_P (XEXP (PATTERN (insn), 0))
&& regno == REGNO (XEXP (PATTERN (insn), 0)))
return true;
/* Check that the regno is not modified. */
id = lra_get_insn_recog_data (insn);
for (reg = id->regs; reg != NULL; reg = reg->next)
if (reg->type != OP_IN && reg->regno == (int) regno)
return false;
static_id = id->insn_static_data;
for (reg = static_id->hard_regs; reg != NULL; reg = reg->next)
if (reg->type != OP_IN && reg->regno == (int) regno)
return false;
if (id->arg_hard_regs != NULL)
for (i = 0; (arg_regno = id->arg_hard_regs[i]) >= 0; i++)
if ((int) regno == (arg_regno >= FIRST_PSEUDO_REGISTER
? arg_regno : arg_regno - FIRST_PSEUDO_REGISTER))
return false;
}
return false;
}
/* Final change of pseudos got hard registers into the corresponding
hard registers and removing temporary clobbers. */
void
@ -821,8 +755,7 @@ lra_final_code_change (void)
if (NONJUMP_INSN_P (insn) && GET_CODE (pat) == SET
&& REG_P (SET_SRC (pat)) && REG_P (SET_DEST (pat))
&& REGNO (SET_SRC (pat)) == REGNO (SET_DEST (pat))
&& (! return_regno_p (REGNO (SET_SRC (pat)))
|| ! regno_in_use_p (insn, REGNO (SET_SRC (pat)))))
&& REGNO (SET_SRC (pat)) >= FIRST_PSEUDO_REGISTER)
{
lra_invalidate_insn_data (insn);
delete_insn (insn);