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(fold, COND_EXPR case): All simplified results must go through pedantic_non_lvalue.

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(fold, COND_EXPR case):  All simplified results
must go through pedantic_non_lvalue.
(pedantic_non_lvalue): New function.

From-SVN: r4867
This commit is contained in:
Jim Wilson 1993-07-06 14:01:14 -07:00
parent f0d568b76d
commit a5e9b1248c
1 changed files with 44 additions and 19 deletions
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63
gcc/fold-const.c
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@ -1672,6 +1672,19 @@ non_lvalue (x)
TREE_CONSTANT (result) = TREE_CONSTANT (x);
return result;
}
/* When pedantic, return an expr equal to X but certainly not valid as a
pedantic lvalue. Otherwise, return X. */
tree
pedantic_non_lvalue (x)
tree x;
{
if (pedantic)
return non_lvalue (x);
else
return x;
}
/* Given a tree comparison code, return the code that is the logical inverse
of the given code. It is not safe to do this for floating-point
@ -4454,10 +4467,13 @@ fold (expr)
return t1;
case COND_EXPR:
/* Pedantic ANSI C says that a conditional expression is never an lvalue,
so all simple results must be passed through pedantic_non_lvalue. */
if (TREE_CODE (arg0) == INTEGER_CST)
return TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1));
return pedantic_non_lvalue
(TREE_OPERAND (t, (integer_zerop (arg0) ? 2 : 1)));
else if (operand_equal_p (arg1, TREE_OPERAND (expr, 2), 0))
return omit_one_operand (type, arg1, arg0);
return pedantic_non_lvalue (omit_one_operand (type, arg1, arg0));
/* If the second operand is zero, invert the comparison and swap
the second and third operands. Likewise if the second operand
@ -4507,16 +4523,19 @@ fold (expr)
switch (comp_code)
{
case EQ_EXPR:
return fold (build1 (NEGATE_EXPR, type, arg1));
return pedantic_non_lvalue
(fold (build1 (NEGATE_EXPR, type, arg1)));
case NE_EXPR:
return convert (type, arg1);
return pedantic_non_lvalue (convert (type, arg1));
case GE_EXPR:
case GT_EXPR:
return fold (build1 (ABS_EXPR, type, arg1));
return pedantic_non_lvalue
(fold (build1 (ABS_EXPR, type, arg1)));
case LE_EXPR:
case LT_EXPR:
return fold (build1 (NEGATE_EXPR, type,
fold (build1 (ABS_EXPR, type, arg1))));
return pedantic_non_lvalue
(fold (build1 (NEGATE_EXPR, type,
fold (build1 (ABS_EXPR, type, arg1)))));
}
/* If this is A != 0 ? A : 0, this is simply A. For ==, it is
@ -4525,9 +4544,9 @@ fold (expr)
if (integer_zerop (TREE_OPERAND (arg0, 1)) && integer_zerop (arg2))
{
if (comp_code == NE_EXPR)
return convert (type, arg1);
return pedantic_non_lvalue (convert (type, arg1));
else if (comp_code == EQ_EXPR)
return convert (type, integer_zero_node);
return pedantic_non_lvalue (convert (type, integer_zero_node));
}
/* If this is A op B ? A : B, this is either A, B, min (A, B),
@ -4538,15 +4557,17 @@ fold (expr)
switch (comp_code)
{
case EQ_EXPR:
return convert (type, arg2);
return pedantic_non_lvalue (convert (type, arg2));
case NE_EXPR:
return convert (type, arg1);
return pedantic_non_lvalue (convert (type, arg1));
case LE_EXPR:
case LT_EXPR:
return fold (build (MIN_EXPR, type, arg1, arg2));
return pedantic_non_lvalue
(fold (build (MIN_EXPR, type, arg1, arg2)));
case GE_EXPR:
case GT_EXPR:
return fold (build (MAX_EXPR, type, arg1, arg2));
return pedantic_non_lvalue
(fold (build (MAX_EXPR, type, arg1, arg2)));
}
/* If this is A op C1 ? A : C2 with C1 and C2 constant integers,
@ -4572,7 +4593,8 @@ fold (expr)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
const_binop (PLUS_EXPR, arg2,
integer_one_node, 0), 1))
return fold (build (MIN_EXPR, type, arg1, arg2));
return pedantic_non_lvalue
(fold (build (MIN_EXPR, type, arg1, arg2)));
break;
case LE_EXPR:
@ -4581,7 +4603,8 @@ fold (expr)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
const_binop (MINUS_EXPR, arg2,
integer_one_node, 0), 1))
return fold (build (MIN_EXPR, type, arg1, arg2));
return pedantic_non_lvalue
(fold (build (MIN_EXPR, type, arg1, arg2)));
break;
case GT_EXPR:
@ -4590,7 +4613,8 @@ fold (expr)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
const_binop (MINUS_EXPR, arg2,
integer_one_node, 0), 1))
return fold (build (MAX_EXPR, type, arg1, arg2));
return pedantic_non_lvalue
(fold (build (MAX_EXPR, type, arg1, arg2)));
break;
case GE_EXPR:
@ -4599,7 +4623,8 @@ fold (expr)
&& operand_equal_p (TREE_OPERAND (arg0, 1),
const_binop (PLUS_EXPR, arg2,
integer_one_node, 0), 1))
return fold (build (MAX_EXPR, type, arg1, arg2));
return pedantic_non_lvalue
(fold (build (MAX_EXPR, type, arg1, arg2)));
break;
}
}
@ -4612,7 +4637,7 @@ fold (expr)
a COND, which will recurse. In that case, the COND_EXPR
is probably the best choice, so leave it alone. */
&& type == TREE_TYPE (arg0))
return arg0;
return pedantic_non_lvalue (arg0);
/* Look for expressions of the form A & 2 ? 2 : 0. The result of this
@ -4625,7 +4650,7 @@ fold (expr)
&& TREE_CODE (TREE_OPERAND (arg0, 0)) == BIT_AND_EXPR
&& operand_equal_p (TREE_OPERAND (TREE_OPERAND (arg0, 0), 1),
arg1, 1))
return convert (type, TREE_OPERAND (arg0, 0));
return pedantic_non_lvalue (convert (type, TREE_OPERAND (arg0, 0)));
return t;