diff options
Diffstat (limited to 'gcc/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index 791f91a..865d37d 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -3250,6 +3250,18 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode, case ROTATERT: case ROTATE: + /* Canonicalize rotates by constant amount. If op1 is bitsize / 2, + prefer left rotation, if op1 is from bitsize / 2 + 1 to + bitsize - 1, use other direction of rotate with 1 .. bitsize / 2 - 1 + amount instead. */ + if (CONST_INT_P (trueop1) + && IN_RANGE (INTVAL (trueop1), + GET_MODE_BITSIZE (mode) / 2 + (code == ROTATE), + GET_MODE_BITSIZE (mode) - 1)) + return simplify_gen_binary (code == ROTATE ? ROTATERT : ROTATE, + mode, op0, GEN_INT (GET_MODE_BITSIZE (mode) + - INTVAL (trueop1))); + /* FALLTHRU */ case ASHIFTRT: if (trueop1 == CONST0_RTX (mode)) return op0; |