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re PR c/11449 (ICE in invert_truthvalue called on AND operation) 

PR c/11449
	* fold-const.c (sign_bit_p): Return EXP if VAL is the sign bit
	of HOST_WIDE_INT.
	(fold_single_bit_test): If sign_bit_p() fails, assume that the
	bit being tested is not a sign bit.

	PR c/11449
	* gcc.c-torture/compile/20030707-1.c: New.
	* config/h8300/h8300.md (a peephole2): New.

From-SVN: r69184
This commit is contained in:
Kazu Hirata 2003-07-10 12:40:10 +00:00
parent bcda12f4f4
commit c87d821bd4
2 changed files with 35 additions and 10 deletions
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32
gcc/fold-const.c
View File

@ -2730,8 +2730,8 @@ all_ones_mask_p (tree mask, int size)
static tree
sign_bit_p (tree exp, tree val)
{
unsigned HOST_WIDE_INT lo;
HOST_WIDE_INT hi;
unsigned HOST_WIDE_INT mask_lo, lo;
HOST_WIDE_INT mask_hi, hi;
int width;
tree t;
@ -2750,14 +2750,25 @@ sign_bit_p (tree exp, tree val)
{
hi = (unsigned HOST_WIDE_INT) 1 << (width - HOST_BITS_PER_WIDE_INT - 1);
lo = 0;
mask_hi = ((unsigned HOST_WIDE_INT) -1
>> (2 * HOST_BITS_PER_WIDE_INT - width));
mask_lo = -1;
}
else
{
hi = 0;
lo = (unsigned HOST_WIDE_INT) 1 << (width - 1);
mask_hi = 0;
mask_lo = ((unsigned HOST_WIDE_INT) -1
>> (HOST_BITS_PER_WIDE_INT - width));
}
if (TREE_INT_CST_HIGH (val) == hi && TREE_INT_CST_LOW (val) == lo)
/* We mask off those bits beyond TREE_TYPE (exp) so that we can
treat VAL as if it were unsigned. */
if ((TREE_INT_CST_HIGH (val) & mask_hi) == hi
&& (TREE_INT_CST_LOW (val) & mask_lo) == lo)
return exp;
/* Handle extension from a narrower type. */
@ -4840,6 +4851,10 @@ fold_single_bit_test (enum tree_code code, tree arg0, tree arg1,
convert (stype, arg00),
convert (stype, integer_zero_node)));
}
/* At this point, we know that arg0 is not testing the sign bit. */
if (TYPE_PRECISION (type) - 1 == bitnum)
abort ();
/* Otherwise we have (A & C) != 0 where C is a single bit,
convert that into ((A >> C2) & 1). Where C2 = log2(C).
@ -4861,13 +4876,11 @@ fold_single_bit_test (enum tree_code code, tree arg0, tree arg1,
/* If we are going to be able to omit the AND below, we must do our
operations as unsigned. If we must use the AND, we have a choice.
Normally unsigned is faster, but for some machines signed is. */
ops_unsigned = (bitnum == TYPE_PRECISION (type) - 1 ? 1
#ifdef LOAD_EXTEND_OP
: (LOAD_EXTEND_OP (operand_mode) == SIGN_EXTEND ? 0 : 1)
ops_unsigned = (LOAD_EXTEND_OP (operand_mode) == SIGN_EXTEND ? 0 : 1);
#else
: 1
ops_unsigned = 1;
#endif
);
signed_type = (*lang_hooks.types.type_for_mode) (operand_mode, 0);
unsigned_type = (*lang_hooks.types.type_for_mode) (operand_mode, 1);
@ -4881,9 +4894,8 @@ fold_single_bit_test (enum tree_code code, tree arg0, tree arg1,
inner, integer_one_node);
/* Put the AND last so it can combine with more things. */
if (bitnum != TYPE_PRECISION (type) - 1)
inner = build (BIT_AND_EXPR, ops_unsigned ? unsigned_type : signed_type,
inner, integer_one_node);
inner = build (BIT_AND_EXPR, ops_unsigned ? unsigned_type : signed_type,
inner, integer_one_node);
/* Make sure to return the proper type. */
if (TREE_TYPE (inner) != result_type)

13
gcc/testsuite/gcc.c-torture/compile/20030707-1.c Normal file
View File

@ -0,0 +1,13 @@
/* PR c/11449. */
/* sign_bit_p() in fold-const.c failed to notice that (int) 0x80000000
was the sign bit of m. As a result, fold_single_bit_test()
returned ((unsigned int) m >> 31), and that was eventually passed
to invert_truthvalue(), which did not know how to handle
RROTATE_EXPR, causing an ICE. */
int
foo (int m)
{
return !(m & ((int) 0x80000000));
}