diff options
Diffstat (limited to 'gcc/simplify-rtx.c')
| -rw-r--r-- | gcc/simplify-rtx.c | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/gcc/simplify-rtx.c b/gcc/simplify-rtx.c index dd91e120d23..16d0d48688d 100644 --- a/gcc/simplify-rtx.c +++ b/gcc/simplify-rtx.c @@ -2304,12 +2304,19 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode, case AND: if (trueop1 == CONST0_RTX (mode) && ! side_effects_p (op0)) return trueop1; - /* If we are turning off bits already known off in OP0, we need - not do an AND. */ if (GET_CODE (trueop1) == CONST_INT - && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT - && (nonzero_bits (trueop0, mode) & ~INTVAL (trueop1)) == 0) - return op0; + && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT) + { + HOST_WIDE_INT nzop0 = nonzero_bits (trueop0, mode); + HOST_WIDE_INT val1 = INTVAL (trueop1); + /* If we are turning off bits already known off in OP0, we need + not do an AND. */ + if ((nzop0 & ~val1) == 0) + return op0; + /* If we are clearing all the nonzero bits, the result is zero. */ + if ((val1 & nzop0) == 0 && !side_effects_p (op0)) + return CONST0_RTX (mode); + } if (rtx_equal_p (trueop0, trueop1) && ! side_effects_p (op0) && GET_MODE_CLASS (mode) != MODE_CC) return op0; @@ -2391,7 +2398,9 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode, ((A & N) + B) & M -> (A + B) & M Similarly if (N & M) == 0, ((A | N) + B) & M -> (A + B) & M - and for - instead of + and/or ^ instead of |. */ + and for - instead of + and/or ^ instead of |. + Also, if (N & M) == 0, then + (A +- N) & M -> A & M. */ if (GET_CODE (trueop1) == CONST_INT && GET_MODE_BITSIZE (mode) <= HOST_BITS_PER_WIDE_INT && ~INTVAL (trueop1) @@ -2404,6 +2413,10 @@ simplify_binary_operation_1 (enum rtx_code code, enum machine_mode mode, pmop[0] = XEXP (op0, 0); pmop[1] = XEXP (op0, 1); + if (GET_CODE (pmop[1]) == CONST_INT + && (INTVAL (pmop[1]) & INTVAL (trueop1)) == 0) + return simplify_gen_binary (AND, mode, pmop[0], op1); + for (which = 0; which < 2; which++) { tem = pmop[which]; @@ -3591,10 +3604,6 @@ simplify_plus_minus (enum rtx_code code, enum machine_mode mode, rtx op0, ops[j + 1] = save; } - /* This is only useful the first time through. */ - if (!canonicalized) - return NULL_RTX; - changed = 0; for (i = n_ops - 1; i > 0; i--) for (j = i - 1; j >= 0; j--) @@ -3650,10 +3659,15 @@ simplify_plus_minus (enum rtx_code code, enum machine_mode mode, rtx op0, ops[i].neg = lneg; ops[j].op = NULL_RTX; changed = 1; + canonicalized = 1; } } } + /* If nothing changed, fail. */ + if (!canonicalized) + return NULL_RTX; + /* Pack all the operands to the lower-numbered entries. */ for (i = 0, j = 0; j < n_ops; j++) if (ops[j].op) |
