OpenE2K
/
gcc
2
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

middle-end/98773 - always sign extend CHREC_RIGHT 

The previous change exposed a miscompile when trying to interpret
CHREC_RIGHT correctly which in fact it already was to the extent
it is used.  The following reverts this part of the change, only
retaining the singling out of HOST_WIDE_INT_MIN.

2021-01-22  Richard Biener  <rguenther@suse.de>

	PR middle-end/98773
	* tree-data-ref.c (initalize_matrix_A): Revert previous
	change, retaining failing on HOST_WIDE_INT_MIN CHREC_RIGHT.

	* gcc.dg/torture/pr98773.c: New testcase.
This commit is contained in:
Richard Biener 2021-01-22 11:29:17 +01:00
parent 36fe1cdc95
commit 8bad25eb56
2 changed files with 22 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
gcc/testsuite/gcc.dg/torture/pr98773.c Normal file
View File

@ -0,0 +1,19 @@
/* { dg-do run } */
char a[128];
void __attribute__((noipa))
foo ()
{
for (unsigned i = 27; i >= 5; --i)
a[i] = a[i-5];
}
int main()
{
__builtin_memcpy (a, "Hello World", sizeof ("Hello World"));
foo ();
if (__builtin_memcmp (a + 5, "Hello World", sizeof ("Hello World")) != 0)
__builtin_abort ();
return 0;
}

17
gcc/tree-data-ref.c
View File

@ -3924,21 +3924,10 @@ initialize_matrix_A (lambda_matrix A, tree chrec, unsigned index, int mult)
switch (TREE_CODE (chrec))
{
case POLYNOMIAL_CHREC:
/* CHREC_RIGHT and its negated value should fit in a lambda_int.
Pointer typed chrecs right are to be interpreted signed. */
HOST_WIDE_INT chrec_right;
if (POINTER_TYPE_P (chrec_type (chrec)))
{
if (!cst_and_fits_in_hwi (CHREC_RIGHT (chrec)))
return chrec_dont_know;
chrec_right = int_cst_value (CHREC_RIGHT (chrec));
}
else
{
if (!tree_fits_shwi_p (CHREC_RIGHT (chrec)))
return chrec_dont_know;
chrec_right = tree_to_shwi (CHREC_RIGHT (chrec));
}
if (!cst_and_fits_in_hwi (CHREC_RIGHT (chrec)))
return chrec_dont_know;
chrec_right = int_cst_value (CHREC_RIGHT (chrec));
/* We want to be able to negate without overflow. */
if (chrec_right == HOST_WIDE_INT_MIN)
return chrec_dont_know;