diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index ecf6741..45d4048 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -6522,14 +6522,22 @@ simplify_if_then_else (rtx x) simplify_shift_const (NULL_RTX, ASHIFT, mode, gen_lowpart (mode, XEXP (cond, 0)), i); - /* (IF_THEN_ELSE (NE REG 0) (0) (8)) is REG for nonzero_bits (REG) == 8. */ + /* (IF_THEN_ELSE (NE A 0) C1 0) is A or a zero-extend of A if the only + non-zero bit in A is C1. */ if (true_code == NE && XEXP (cond, 1) == const0_rtx && false_rtx == const0_rtx && CONST_INT_P (true_rtx) - && GET_MODE (XEXP (cond, 0)) == mode + && INTEGRAL_MODE_P (GET_MODE (XEXP (cond, 0))) && (UINTVAL (true_rtx) & GET_MODE_MASK (mode)) - == nonzero_bits (XEXP (cond, 0), mode) + == nonzero_bits (XEXP (cond, 0), GET_MODE (XEXP (cond, 0))) && (i = exact_log2 (UINTVAL (true_rtx) & GET_MODE_MASK (mode))) >= 0) - return XEXP (cond, 0); + { + rtx val = XEXP (cond, 0); + enum machine_mode val_mode = GET_MODE (val); + if (val_mode == mode) + return val; + else if (GET_MODE_PRECISION (val_mode) < GET_MODE_PRECISION (mode)) + return simplify_gen_unary (ZERO_EXTEND, mode, val, val_mode); + } return x; } |