From 9f8e169eb7a21b2f374df31dd32beef667676a13 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 18 Sep 2000 11:39:03 -0700 Subject: combine.c (simplify_comparison): Shift a NOT out of a single bit test. * combine.c (simplify_comparison): Shift a NOT out of a single bit test. From-SVN: r36508 --- gcc/combine.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) (limited to 'gcc/combine.c') diff --git a/gcc/combine.c b/gcc/combine.c index b8ac09b..a498b58 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -10811,6 +10811,21 @@ simplify_comparison (code, pop0, pop1) continue; } + /* Convert (ne (and (lshiftrt (not X)) 1) 0) to + (eq (and (lshiftrt X) 1) 0). */ + 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_combine (LSHIFTRT, mode, + XEXP (XEXP (XEXP (op0, 0), 0), 0), + XEXP (XEXP (op0, 0), 1)), + (HOST_WIDE_INT) 1); + code = (code == NE ? EQ : NE); + continue; + } break; case ASHIFT: -- cgit v1.1