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avr.md (peephole casesi+2): Use -1 instead of 65536.

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* config/avr/avr.md (peephole casesi+2): Use -1 instead of 65536.
	* config/avr/avr.c (avr_out_compare): Print shorter sequence for
	EQ/NE comparisons against +/-1 in the case of unused-after,
	non-ld-regs target.

From-SVN: r179206
This commit is contained in:
Georg-Johann Lay 2011-09-26 16:55:55 +00:00 • committed by Georg-Johann Lay
parent 2186081438
commit 31fd727b4d
3 changed files with 39 additions and 1 deletions
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7
gcc/ChangeLog
View file

@ -1,3 +1,10 @@
2011-09-26 Georg-Johann Lay <avr@gjlay.de>
* config/avr/avr.md (peephole casesi+2): Use -1 instead of 65536.
* config/avr/avr.c (avr_out_compare): Print shorter sequence for
EQ/NE comparisons against +/-1 in the case of unused-after,
non-ld-regs target.
2011-09-26 Jakub Jelinek <jakub@redhat.com>
* gimple-fold.c (gimplify_and_update_call_from_tree): Set

31
gcc/config/avr/avr.c
View file

@ -3048,6 +3048,37 @@ avr_out_compare (rtx insn, rtx *xop, int *plen)
if (plen)
*plen = 0;
/* Comparisons == +/-1 and != +/-1 can be done similar to camparing
against 0 by ORing the bytes. This is one instruction shorter. */
if (!test_hard_reg_class (LD_REGS, xreg)
&& compare_eq_p (insn)
&& reg_unused_after (insn, xreg))
{
if (xval == const1_rtx)
{
avr_asm_len ("dec %A0" CR_TAB
"or %A0,%B0", xop, plen, 2);
if (n_bytes == 4)
avr_asm_len ("or %A0,%C0" CR_TAB
"or %A0,%D0", xop, plen, 2);
return "";
}
else if (xval == constm1_rtx)
{
if (n_bytes == 4)
avr_asm_len ("and %A0,%D0" CR_TAB
"and %A0,%C0", xop, plen, 2);
avr_asm_len ("and %A0,%B0" CR_TAB
"com %A0", xop, plen, 2);
return "";
}
}
for (i = 0; i < n_bytes; i++)
{
/* We compare byte-wise. */

2
gcc/config/avr/avr.md
View file

@ -4119,7 +4119,7 @@
(parallel
[(set (cc0)
(compare (match_dup 0)
(const_int 65535)))
(const_int -1)))
(clobber (match_operand:QI 1 "d_register_operand" ""))])
(set (pc)
(if_then_else (ne (cc0) (const_int 0))