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re PR rtl-optimization/90257 (8% degradation on cpu2006 403.gcc starting with r270484) 

PR rtl-optimization/90257
	* cfgrtl.c (flow_active_insn_p): Return true for USE of a function
	return value.

	Revert the revert:
	2019-04-21  H.J. Lu  <hongjiu.lu@intel.com>

	PR target/90178
	Revert:
	2018-11-21  Uros Bizjak  <ubizjak@gmail.com>

	Revert the revert:
	2013-10-26  Vladimir Makarov  <vmakarov@redhat.com>

	Revert:
	2013-10-25  Vladimir Makarov  <vmakarov@redhat.com>

	* lra-spills.c (lra_final_code_change): Remove useless move insns.

From-SVN: r270653
This commit is contained in:
Jakub Jelinek 2019-04-29 16:18:55 +02:00 committed by Jakub Jelinek
parent 4e29671cb2
commit 1008df90cc
3 changed files with 43 additions and 3 deletions
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21
gcc/ChangeLog
View File

@ -1,3 +1,24 @@
2019-04-29 Jakub Jelinek <jakub@redhat.com>
PR rtl-optimization/90257
* cfgrtl.c (flow_active_insn_p): Return true for USE of a function
return value.
Revert the revert:
2019-04-21 H.J. Lu <hongjiu.lu@intel.com>
PR target/90178
Revert:
2018-11-21 Uros Bizjak <ubizjak@gmail.com>
Revert the revert:
2013-10-26 Vladimir Makarov <vmakarov@redhat.com>
Revert:
2013-10-25 Vladimir Makarov <vmakarov@redhat.com>
* lra-spills.c (lra_final_code_change): Remove useless move insns.
2019-04-29 Richard Biener <rguenther@suse.de>
* tree-ssa.c (insert_debug_temp_for_var_def): For {CLOBBER}

10
gcc/cfgrtl.c
View File

@ -543,7 +543,7 @@ update_bb_for_insn (basic_block bb)
}
/* Like active_insn_p, except keep the return value clobber around
/* Like active_insn_p, except keep the return value use or clobber around
even after reload. */
static bool
@ -556,8 +556,12 @@ flow_active_insn_p (const rtx_insn *insn)
programs that fail to return a value. Its effect is to
keep the return value from being live across the entire
function. If we allow it to be skipped, we introduce the
possibility for register lifetime confusion. */
if (GET_CODE (PATTERN (insn)) == CLOBBER
possibility for register lifetime confusion.
Similarly, keep a USE of the function return value, otherwise
the USE is dropped and we could fail to thread jump if USE
appears on some paths and not on others, see PR90257. */
if ((GET_CODE (PATTERN (insn)) == CLOBBER
|| GET_CODE (PATTERN (insn)) == USE)
&& REG_P (XEXP (PATTERN (insn), 0))
&& REG_FUNCTION_VALUE_P (XEXP (PATTERN (insn), 0)))
return true;

15
gcc/lra-spills.c
View File

@ -740,6 +740,7 @@ lra_final_code_change (void)
int i, hard_regno;
basic_block bb;
rtx_insn *insn, *curr;
rtx set;
int max_regno = max_reg_num ();
for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
@ -818,5 +819,19 @@ lra_final_code_change (void)
}
if (insn_change_p)
lra_update_operator_dups (id);
if ((set = single_set (insn)) != NULL
&& REG_P (SET_SRC (set)) && REG_P (SET_DEST (set))
&& REGNO (SET_SRC (set)) == REGNO (SET_DEST (set)))
{
/* Remove an useless move insn. IRA can generate move
insns involving pseudos. It is better remove them
earlier to speed up compiler a bit. It is also
better to do it here as they might not pass final RTL
check in LRA, (e.g. insn moving a control register
into itself). */
lra_invalidate_insn_data (insn);
delete_insn (insn);
}
}
}