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re PR rtl-optimization/70478 ([LRA] S/390: Performance regression - superfluous stack frame) 

2017-04-10  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/70478
	* lra-constraints.c (curr_small_class_check): New.
	(update_and_check_small_class_inputs): New.
	(process_alt_operands): Update curr_small_class_check.  Disfavor
	alternative insn memory operands.  Check available regs for small
	class operands.

From-SVN: r246808
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Vladimir Makarov 2017-04-10 14:58:33 +00:00 committed by Vladimir Makarov
parent 1246dc4067
commit 9b195552ab
2 changed files with 69 additions and 0 deletions
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@ -1,3 +1,12 @@
2017-04-10 Vladimir Makarov <vmakarov@redhat.com>
PR rtl-optimization/70478
* lra-constraints.c (curr_small_class_check): New.
(update_and_check_small_class_inputs): New.
(process_alt_operands): Update curr_small_class_check. Disfavor
alternative insn memory operands. Check available regs for small
class operands.
2017-03-31 Matthew Fortune <matthew.fortune@imgtec.com>
PR target/80057

60
gcc/lra-constraints.c
View File

@ -1852,6 +1852,42 @@ prohibited_class_reg_set_mode_p (enum reg_class rclass,
(temp, ira_prohibited_class_mode_regs[rclass][mode]));
}
/* Used to check validity info about small class input operands. It
should be incremented at start of processing an insn
alternative. */
static unsigned int curr_small_class_check = 0;
/* Update number of used inputs of class OP_CLASS for operand NOP.
Return true if we have more such class operands than the number of
available regs. */
static bool
update_and_check_small_class_inputs (int nop, enum reg_class op_class)
{
static unsigned int small_class_check[LIM_REG_CLASSES];
static int small_class_input_nums[LIM_REG_CLASSES];
if (SMALL_REGISTER_CLASS_P (op_class)
/* We are interesting in classes became small because of fixing
some hard regs, e.g. by an user through GCC options. */
&& hard_reg_set_intersect_p (reg_class_contents[op_class],
ira_no_alloc_regs)
&& (curr_static_id->operand[nop].type != OP_OUT
|| curr_static_id->operand[nop].early_clobber))
{
if (small_class_check[op_class] == curr_small_class_check)
small_class_input_nums[op_class]++;
else
{
small_class_check[op_class] = curr_small_class_check;
small_class_input_nums[op_class] = 1;
}
if (small_class_input_nums[op_class] > ira_class_hard_regs_num[op_class])
return true;
}
return false;
}
/* Major function to choose the current insn alternative and what
operands should be reloaded and how. If ONLY_ALTERNATIVE is not
negative we should consider only this alternative. Return false if
@ -1952,6 +1988,7 @@ process_alt_operands (int only_alternative)
if (!TEST_BIT (preferred, nalt))
continue;
curr_small_class_check++;
overall = losers = addr_losers = 0;
static_reject = reject = reload_nregs = reload_sum = 0;
for (nop = 0; nop < n_operands; nop++)
@ -2685,6 +2722,21 @@ process_alt_operands (int only_alternative)
}
}
/* When we use memory operand, the insn should read the
value from memory and even if we just wrote a value
into the memory it is costly in comparison with an
insn alternative which does not use memory
(e.g. register or immediate operand). */
if (no_regs_p && offmemok)
{
if (lra_dump_file != NULL)
fprintf
(lra_dump_file,
" Using memory insn operand %d: reject+=3\n",
nop);
reject += 3;
}
#ifdef SECONDARY_MEMORY_NEEDED
/* If reload requires moving value through secondary
memory, it will need one more insn at least. */
@ -2747,6 +2799,14 @@ process_alt_operands (int only_alternative)
goto fail;
}
if (update_and_check_small_class_inputs (nop, this_alternative))
{
if (lra_dump_file != NULL)
fprintf (lra_dump_file,
" alt=%d, not enough small class regs -- refuse\n",
nalt);
goto fail;
}
curr_alt[nop] = this_alternative;
COPY_HARD_REG_SET (curr_alt_set[nop], this_alternative_set);
curr_alt_win[nop] = this_alternative_win;