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| author | Kazu Hirata <kazu@cs.umass.edu> | 2003-09-14 18:31:13 +0000 |
|---|---|---|
| committer | Kazu Hirata <kazu@gcc.gnu.org> | 2003-09-14 18:31:13 +0000 |
| commit | 5565e8744fd07733385f1925c8b949b6be5fa60a (patch) | |
| tree | a5b0797e155ac4bac07ebe1b9ec20cf022d82477 /gcc/combine.c | |
| parent | 83a00410f54676140ee0aa3f057f99ea6086d8a2 (diff) | |
| download | gcc-5565e8744fd07733385f1925c8b949b6be5fa60a.zip gcc-5565e8744fd07733385f1925c8b949b6be5fa60a.tar.gz gcc-5565e8744fd07733385f1925c8b949b6be5fa60a.tar.bz2 | |
combine.c (simplify_comparison): Convert (ne (and (lshiftrt (xor X CST) Y) 1) 0) into (eq (and (lshiftrt X Y) 1) 0).
* combine.c (simplify_comparison): Convert
(ne (and (lshiftrt (xor X CST) Y) 1) 0) into
(eq (and (lshiftrt X Y) 1) 0).
From-SVN: r71385
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 33 |
1 files changed, 22 insertions, 11 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 2567ca9..c18c36e 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -10983,19 +10983,30 @@ simplify_comparison (enum rtx_code code, rtx *pop0, rtx *pop1) } /* Convert (ne (and (lshiftrt (not X)) 1) 0) to - (eq (and (lshiftrt X) 1) 0). */ + (eq (and (lshiftrt X) 1) 0). + Also handle the case where (not X) is expressed using xor. */ if (const_op == 0 && equality_comparison_p && XEXP (op0, 1) == const1_rtx - && GET_CODE (XEXP (op0, 0)) == LSHIFTRT - && GET_CODE (XEXP (XEXP (op0, 0), 0)) == NOT) - { - op0 = simplify_and_const_int - (op0, mode, - gen_rtx_LSHIFTRT (mode, XEXP (XEXP (XEXP (op0, 0), 0), 0), - XEXP (XEXP (op0, 0), 1)), - (HOST_WIDE_INT) 1); - code = (code == NE ? EQ : NE); - continue; + && GET_CODE (XEXP (op0, 0)) == LSHIFTRT) + { + rtx shift_op = XEXP (XEXP (op0, 0), 0); + rtx shift_count = XEXP (XEXP (op0, 0), 1); + + if (GET_CODE (shift_op) == NOT + || (GET_CODE (shift_op) == XOR + && GET_CODE (XEXP (shift_op, 1)) == CONST_INT + && GET_CODE (shift_count) == CONST_INT + && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT + && (INTVAL (XEXP (shift_op, 1)) + == (HOST_WIDE_INT) 1 << INTVAL (shift_count)))) + { + op0 = simplify_and_const_int + (NULL_RTX, mode, + gen_rtx_LSHIFTRT (mode, XEXP (shift_op, 0), shift_count), + (HOST_WIDE_INT) 1); + code = (code == NE ? EQ : NE); + continue; + } } break; |