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Suspicious code in fold-const.c
- From: Andrew MacLeod <amacleod at redhat dot com>
- To: gcc-patches <gcc-patches at gcc dot gnu dot org>
- Date: Thu, 21 Jan 2016 18:06:35 -0500
- Subject: Suspicious code in fold-const.c
- Authentication-results: sourceware.org; auth=none
I was trying the ttype prototype for static type checking on
fold-const.c to see how long it would take me to convert such a large
file, and it choked on this snippet of code in fold_unary_loc, around
lines 7690-7711:
suspect code tagged with (*)
if ((CONVERT_EXPR_CODE_P (code)
|| code == NON_LVALUE_EXPR)
&& TREE_CODE (tem) == COND_EXPR
&& TREE_CODE (TREE_OPERAND (tem, 1)) == code
&& TREE_CODE (TREE_OPERAND (tem, 2)) == code
(*) && ! VOID_TYPE_P (TREE_OPERAND (tem, 1))
(*) && ! VOID_TYPE_P (TREE_OPERAND (tem, 2))
&& (TREE_TYPE (TREE_OPERAND (TREE_OPERAND (tem, 1), 0))
== TREE_TYPE (TREE_OPERAND (TREE_OPERAND (tem, 2), 0)))
&& (! (INTEGRAL_TYPE_P (TREE_TYPE (tem))
&& (INTEGRAL_TYPE_P
(TREE_TYPE (TREE_OPERAND (TREE_OPERAND (tem,
1), 0))))
&& TYPE_PRECISION (TREE_TYPE (tem)) <= BITS_PER_WORD)
|| flag_syntax_only))
tem = build1_loc (loc, code, type,
build3 (COND_EXPR,
TREE_TYPE (TREE_OPERAND
(TREE_OPERAND (tem,
1), 0)),
TREE_OPERAND (tem, 0),
TREE_OPERAND (TREE_OPERAND (tem,
1), 0),
TREE_OPERAND (TREE_OPERAND (tem, 2),
0)));
and with:
#define VOID_TYPE_P(NODE) (TREE_CODE (NODE) == VOID_TYPE)
I don't think this is what was intended. it would expand into:
&& TREE_CODE (TREE_OPERAND (tem, 1)) == code
&& TREE_CODE (TREE_OPERAND (tem, 2)) == code
&& ! (TREE_CODE (TREE_OPERAND (tem, 1)) == VOID_TYPE)
&& ! (TREE_CODE (TREE_OPERAND (tem, 2)) == VOID_TYPE)
the latter two would be obviously true if the first 2 were true.
My guess is this is probably suppose to be
&& ! VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (tem, 1)))
&& ! VOID_TYPE_P (TREE_TYPE (TREE_OPERAND (tem, 2)))
but I'm not sure. Any guesses whats intended here?
Andrew