This patch adjusts the spill cost of literal pool loads to reduce the chance of
them being
caller-saved (which is inefficient). Such loads should be rematerialized and
thus should not include
the cost of a spill store. This was done only on constants for which
legitimate_constant_p is true,
however it is right thing to do for any constant, including constants in
literal pools (which are
typically not legitimate). Also use ALL_REGS rather than GENERAL_REGS as
ALL_REGS has the correct
floating point register costs.
ChangeLog:
2014-10-29 Wilco Dijkstra <wdijk...@arm.com>
* gcc/ira-costs.c (scan_one_insn): Improve spill cost adjustment.
---
gcc/ira-costs.c | 7 +++----
1 file changed, 3 insertions(+), 4 deletions(-)
diff --git a/gcc/ira-costs.c b/gcc/ira-costs.c
index 122815b..c4a1934 100644
--- a/gcc/ira-costs.c
+++ b/gcc/ira-costs.c
@@ -1455,19 +1455,18 @@ scan_one_insn (rtx_insn *insn)
mem_cost might result in it being loaded using the specialized
instruction into a register, then stored into stack and loaded
again from the stack. See PR52208.
-
+
Don't do this if SET_SRC (set) has side effect. See PR56124. */
if (set != 0 && REG_P (SET_DEST (set)) && MEM_P (SET_SRC (set))
&& (note = find_reg_note (insn, REG_EQUIV, NULL_RTX)) != NULL_RTX
&& ((MEM_P (XEXP (note, 0))
&& !side_effects_p (SET_SRC (set)))
|| (CONSTANT_P (XEXP (note, 0))
- && targetm.legitimate_constant_p (GET_MODE (SET_DEST (set)),
- XEXP (note, 0))
+ && (! flag_pic || LEGITIMATE_PIC_OPERAND_P (XEXP (note, 0)))
&& REG_N_SETS (REGNO (SET_DEST (set))) == 1))
&& general_operand (SET_SRC (set), GET_MODE (SET_SRC (set))))
{
- enum reg_class cl = GENERAL_REGS;
+ enum reg_class cl = ALL_REGS;
rtx reg = SET_DEST (set);
int num = COST_INDEX (REGNO (reg));
--
1.9.1
