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cris: Don't discriminate against ALL_REGS in TARGET_REGISTER_MOVE_COST

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When the tightest class including both SPECIAL_REGS and GENERAL_REGS
is ALL_REGS, artificially special-casing for *either* to or from, hits
artificially hard.  This gets the port back to the code quality before
the previous patch ("cris: Remove CRIS v32 ACR artefacts") - except
for_vfprintf_r and _vfiprintf_r in newlib (still .8 and .4% larger).

gcc:
	* config/cris/cris.cc (cris_register_move_cost): Remove special pre-ira
	extra cost for ALL_REGS.
This commit is contained in:
Hans-Peter Nilsson 2022-02-02 00:00:10 +01:00
parent 27e35bc491
commit 9a7f14ef9b
1 changed files with 3 additions and 13 deletions
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16
gcc/config/cris/cris.cc
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@ -1683,20 +1683,10 @@ cris_register_move_cost (machine_mode mode ATTRIBUTE_UNUSED,
their move cost within that class is higher. How about 7? That's 3
for a move to a GENERAL_REGS register, 3 for the move from the
GENERAL_REGS register, and 1 for the increased register pressure.
Also, it's higher than the memory move cost, as it should.
We also do this for ALL_REGS, since we don't want that class to be
preferred (even to memory) at all where GENERAL_REGS doesn't fit.
Whenever it's about to be used, it's for SPECIAL_REGS. If we don't
present a higher cost for ALL_REGS than memory, a SPECIAL_REGS may be
used when a GENERAL_REGS should be used, even if there are call-saved
GENERAL_REGS left to allocate. This is because the fall-back when
the most preferred register class isn't available, isn't the next
(or next good) wider register class, but the *most widest* register
class. FIXME: pre-IRA comment, perhaps obsolete now. */
Also, it's higher than the memory move cost, as it should be. */
if ((reg_classes_intersect_p (from, SPECIAL_REGS)
&& reg_classes_intersect_p (to, SPECIAL_REGS))
|| from == ALL_REGS || to == ALL_REGS)
if (reg_classes_intersect_p (from, SPECIAL_REGS)
&& reg_classes_intersect_p (to, SPECIAL_REGS))
return 7;
/* Make moves to/from SPECIAL_REGS slightly more expensive, as we