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fix bit test type problem
- From: Richard Henderson <rth at twiddle dot net>
- To: gcc-patches at gcc dot gnu dot org
- Date: Wed, 29 Oct 2003 18:32:17 -0800
- Subject: fix bit test type problem
Found this via miscompilation on tree-ssa branch.
We don't mind type semantics properly during the manipulation,
which leads to TREE_OVERFLOW being set when it shouldn't be.
r~
* fold-const.c (fold_single_bit_test): Convert the input to the
operational intermediate type.
Index: gcc/fold-const.c
===================================================================
RCS file: /cvs/gcc/gcc/gcc/fold-const.c,v
retrieving revision 1.213.2.54
diff -u -p -u -r1.213.2.54 fold-const.c
--- gcc/fold-const.c 24 Oct 2003 23:45:35 -0000 1.213.2.54
+++ gcc/fold-const.c 30 Oct 2003 02:12:29 -0000
@@ -5022,7 +5022,7 @@ fold_single_bit_test (enum tree_code cod
int bitnum = tree_log2 (TREE_OPERAND (arg0, 1));
enum machine_mode operand_mode = TYPE_MODE (type);
int ops_unsigned;
- tree signed_type, unsigned_type;
+ tree signed_type, unsigned_type, intermediate_type;
tree arg00;
/* If we have (A & C) != 0 where C is the sign bit of A, convert
@@ -5068,22 +5068,23 @@ fold_single_bit_test (enum tree_code cod
signed_type = (*lang_hooks.types.type_for_mode) (operand_mode, 0);
unsigned_type = (*lang_hooks.types.type_for_mode) (operand_mode, 1);
+ intermediate_type = ops_unsigned ? unsigned_type : signed_type;
+ inner = convert (intermediate_type, inner);
if (bitnum != 0)
- inner = build (RSHIFT_EXPR, ops_unsigned ? unsigned_type : signed_type,
+ inner = build (RSHIFT_EXPR, intermediate_type,
inner, size_int (bitnum));
if (code == EQ_EXPR)
- inner = build (BIT_XOR_EXPR, ops_unsigned ? unsigned_type : signed_type,
+ inner = build (BIT_XOR_EXPR, intermediate_type,
inner, integer_one_node);
/* Put the AND last so it can combine with more things. */
- inner = build (BIT_AND_EXPR, ops_unsigned ? unsigned_type : signed_type,
+ inner = build (BIT_AND_EXPR, intermediate_type,
inner, integer_one_node);
/* Make sure to return the proper type. */
- if (TREE_TYPE (inner) != result_type)
- inner = convert (result_type, inner);
+ inner = convert (result_type, inner);
return inner;
}