diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 65 |
1 files changed, 47 insertions, 18 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index 6acbe0baf34..f260ab4b500 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -2131,7 +2131,7 @@ operand_equal_p (arg0, arg1, only_const) case STRING_CST: return (TREE_STRING_LENGTH (arg0) == TREE_STRING_LENGTH (arg1) - && ! strncmp (TREE_STRING_POINTER (arg0), + && ! memcmp (TREE_STRING_POINTER (arg0), TREE_STRING_POINTER (arg1), TREE_STRING_LENGTH (arg0))); @@ -2177,6 +2177,12 @@ operand_equal_p (arg0, arg1, only_const) TREE_OPERAND (arg1, 0), 0)); case 'r': + /* If either of the pointer (or reference) expressions we are dereferencing + contain a side effect, these cannot be equal. */ + if (TREE_SIDE_EFFECTS (arg0) + || TREE_SIDE_EFFECTS (arg1)) + return 0; + switch (TREE_CODE (arg0)) { case INDIRECT_REF: @@ -3253,8 +3259,17 @@ make_range (exp, pin_p, plow, phigh) low = range_binop (PLUS_EXPR, type, n_high, 0, integer_one_node, 0); high = range_binop (MINUS_EXPR, type, n_low, 0, - integer_one_node, 0); - in_p = ! in_p; + integer_one_node, 0); + + /* If the range is of the form +/- [ x+1, x ], we won't + be able to normalize it. But then, it represents the + whole range or the empty set, so make it +/- [ -, - ]. + */ + if (tree_int_cst_equal (n_low, low) + && tree_int_cst_equal (n_high, high)) + low = high = 0; + else + in_p = ! in_p; } else low = n_low, high = n_high; @@ -3806,11 +3821,10 @@ fold_truthop (code, truth_type, lhs, rhs) { if (l_const && integer_zerop (l_const) && integer_pow2p (ll_mask)) { - /* Do not sign extend the constant here. The left operand - is either always unsigned or there is a BIT_AND_EXPR that - masks out the extension bits. */ - if (! (ll_unsignedp || ll_and_mask != 0)) - abort (); + /* Make the left operand unsigned, since we are only interested + in the value of one bit. Otherwise we are doing the wrong + thing below. */ + ll_unsignedp = 1; l_const = ll_mask; } else @@ -3822,8 +3836,7 @@ fold_truthop (code, truth_type, lhs, rhs) { if (r_const && integer_zerop (r_const) && integer_pow2p (rl_mask)) { - if (! (rl_unsignedp || rl_and_mask != 0)) - abort (); + rl_unsignedp = 1; r_const = rl_mask; } else @@ -5621,7 +5634,15 @@ fold (expr) tree newconst = fold (build (PLUS_EXPR, TREE_TYPE (varop), constop, TREE_OPERAND (varop, 1))); - TREE_SET_CODE (varop, PREINCREMENT_EXPR); + + /* Do not overwrite the current varop to be a preincrement, + create a new node so that we won't confuse our caller who + might create trees and throw them away, reusing the + arguments that they passed to build. This shows up in + the THEN or ELSE parts of ?: being postincrements. */ + varop = build (PREINCREMENT_EXPR, TREE_TYPE (varop), + TREE_OPERAND (varop, 0), + TREE_OPERAND (varop, 1)); /* If VAROP is a reference to a bitfield, we must mask the constant by the width of the field. */ @@ -5665,9 +5686,9 @@ fold (expr) } - t = build (code, type, TREE_OPERAND (t, 0), - TREE_OPERAND (t, 1)); - TREE_OPERAND (t, constopnum) = newconst; + t = build (code, type, + (constopnum == 0) ? newconst : varop, + (constopnum == 1) ? newconst : varop); return t; } } @@ -5680,7 +5701,15 @@ fold (expr) tree newconst = fold (build (MINUS_EXPR, TREE_TYPE (varop), constop, TREE_OPERAND (varop, 1))); - TREE_SET_CODE (varop, PREDECREMENT_EXPR); + + /* Do not overwrite the current varop to be a predecrement, + create a new node so that we won't confuse our caller who + might create trees and throw them away, reusing the + arguments that they passed to build. This shows up in + the THEN or ELSE parts of ?: being postdecrements. */ + varop = build (PREDECREMENT_EXPR, TREE_TYPE (varop), + TREE_OPERAND (varop, 0), + TREE_OPERAND (varop, 1)); if (TREE_CODE (TREE_OPERAND (varop, 0)) == COMPONENT_REF && DECL_BIT_FIELD(TREE_OPERAND @@ -5719,9 +5748,9 @@ fold (expr) } - t = build (code, type, TREE_OPERAND (t, 0), - TREE_OPERAND (t, 1)); - TREE_OPERAND (t, constopnum) = newconst; + t = build (code, type, + (constopnum == 0) ? newconst : varop, + (constopnum == 1) ? newconst : varop); return t; } } |