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Revert "[PATCH v2] In the pipeline, USE or CLOBBER should delay execution if it starts a new live range."

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This reverts commit 85b49ad863.
This commit is contained in:
Jeff Law 2023-11-12 11:00:12 -07:00
parent 4b754091be
commit 93e92b2e5d
1 changed files with 5 additions and 50 deletions
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55
gcc/haifa-sched.cc
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@ -765,23 +765,6 @@ real_insn_for_shadow (rtx_insn *insn)
return pair->i1;
}
/* Return TRUE if INSN (a USE or CLOBBER) starts a new live
range, FALSE otherwise. */
static bool
use_or_clobber_starts_range_p (rtx_insn *insn)
{
gcc_assert (insn);
if ((GET_CODE (PATTERN (insn)) == CLOBBER
|| GET_CODE (PATTERN (insn)) == USE)
&& !sd_lists_empty_p (insn, SD_LIST_FORW)
&& sd_lists_empty_p (insn, SD_LIST_BACK))
return true;
return false;
}
/* For a pair P of insns, return the fixed distance in cycles from the first
insn after which the second must be scheduled. */
static int
@ -6337,39 +6320,11 @@ prune_ready_list (state_t temp_state, bool first_cycle_insn_p,
}
else if (recog_memoized (insn) < 0)
{
if (GET_CODE (PATTERN (insn)) == ASM_INPUT
|| asm_noperands (PATTERN (insn)) >= 0)
{
reason = "asm";
if (!first_cycle_insn_p)
cost = 1;
}
else if (use_or_clobber_starts_range_p (insn))
{
/* If USE or CLOBBER opens an active range, its execution should
be delayed so as to be closer to the relevant instructions and
avoid the generation of some redundant mov instructions.
Otherwise, it should be executed as soon as possible. */
reason = "unrecog insn";
if (!first_cycle_insn_p)
/* If USE or CLOBBER is not in the first cycle, simply delay it
by one cycle. */
cost = 1;
else
{
/* If the USE or CLOBBER is in the first cycle and there are no
other non-USE or non-CLOBBER instructions after it, we need
to execute it immediately, otherwise we need to execute the
non-USE or non-CLOBBER instructions first and postpone the
execution of the USE or CLOBBER instructions. */
int j = i;
while (n > ++j)
if (!use_or_clobber_starts_range_p (ready_element (&ready, j)))
break;
cost = (j == n) ? 0 : 1;
}
}
if (!first_cycle_insn_p
&& (GET_CODE (PATTERN (insn)) == ASM_INPUT
|| asm_noperands (PATTERN (insn)) >= 0))
cost = 1;
reason = "asm";
}
else if (sched_pressure != SCHED_PRESSURE_NONE)
{