diff options
Diffstat (limited to 'gcc/combine.c')
| -rw-r--r-- | gcc/combine.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/gcc/combine.c b/gcc/combine.c index 559ee15..98efe3e 100644 --- a/gcc/combine.c +++ b/gcc/combine.c @@ -9022,6 +9022,26 @@ simplify_shift_const (rtx x, enum rtx_code code, varop = XEXP (varop, 0); continue; } + + /* Check for 'PLUS signbit', which is the canonical form of 'XOR + signbit', and attempt to change the PLUS to an XOR and move it to + the outer operation as is done above in the AND/IOR/XOR case + leg for shift(logical). See details in logical handling above + for reasoning in doing so. */ + if (code == LSHIFTRT + && GET_CODE (XEXP (varop, 1)) == CONST_INT + && mode_signbit_p (result_mode, XEXP (varop, 1)) + && (new = simplify_binary_operation (code, result_mode, + XEXP (varop, 1), + GEN_INT (count))) != 0 + && GET_CODE (new) == CONST_INT + && merge_outer_ops (&outer_op, &outer_const, XOR, + INTVAL (new), result_mode, &complement_p)) + { + varop = XEXP (varop, 0); + continue; + } + break; case MINUS: |