The following patch fixes PR70450 where I (again...) was not able
to decipher wide-int workings in a first try. (the 'sign' op
looks redundant for a tree wide_int::from so I was thinking it
must apply to the destination to specify eventual zero/sign-extension
if the 'precision' arg is not a multiple of HWI bits - appearantly
a case that needs to be handled separately - I wonder about
lurking bits in other similar users for this case).
Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
Richard.
2016-03-30 Richard Biener <rguent...@suse.de>
PR middle-end/70450
* fold-const.c (extract_muldiv_1): Fix thinko in wide_int::from
usage.
* gcc.dg/torture/pr70450.c: New testcase.
Index: gcc/fold-const.c
===================================================================
*** gcc/fold-const.c (revision 234546)
--- gcc/fold-const.c (working copy)
*************** extract_muldiv_1 (tree t, tree c, enum t
*** 6375,6382 ****
bool overflow_mul_p;
signop sign = TYPE_SIGN (ctype);
unsigned prec = TYPE_PRECISION (ctype);
! wide_int mul = wi::mul (wide_int::from (op1, prec, sign),
! wide_int::from (c, prec, sign),
sign, &overflow_mul_p);
overflow_p = TREE_OVERFLOW (c) | TREE_OVERFLOW (op1);
if (overflow_mul_p
--- 6375,6384 ----
bool overflow_mul_p;
signop sign = TYPE_SIGN (ctype);
unsigned prec = TYPE_PRECISION (ctype);
! wide_int mul = wi::mul (wide_int::from (op1, prec,
! TYPE_SIGN (TREE_TYPE (op1))),
! wide_int::from (c, prec,
! TYPE_SIGN (TREE_TYPE (c))),
sign, &overflow_mul_p);
overflow_p = TREE_OVERFLOW (c) | TREE_OVERFLOW (op1);
if (overflow_mul_p
Index: gcc/testsuite/gcc.dg/torture/pr70450.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr70450.c (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr70450.c (working copy)
***************
*** 0 ****
--- 1,19 ----
+ /* { dg-do run } */
+ /* { dg-require-effective-target lp64 } */
+
+ unsigned long int a = 2UL;
+ int b = 2;
+ unsigned long int c = 2UL;
+
+ void foo ()
+ {
+ c = 2 * ((2 * a) * (2 * (-b)));
+ }
+
+ int main ()
+ {
+ foo();
+ if (c != 18446744073709551584UL)
+ __builtin_abort();
+ return 0;
+ }
