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| -rw-r--r-- | gcc/ChangeLog | 3 | ||||
| -rw-r--r-- | gcc/combine.c | 15 |
2 files changed, 18 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ec5c663..047adf8 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,5 +1,8 @@ 2000-09-18 Richard Henderson <rth@cygnus.com> + * combine.c (simplify_comparison): Shift a NOT out of a single + bit test. + * combine.c (if_then_else_cond): Canonicalize BImode true to STORE_FLAG_VALUE. * explow.c (trunc_int_for_mode): Likewise. 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: |