[Bug tree-optimization/78608] gimple-ssa-sprintf.c:570:17: runtime error: negation of -9223372036854775808 cannot be represented in type 'long int'

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78608

Martin Sebor  changed:

   What|Removed |Added

   Keywords|ice-on-invalid-code |patch

--- Comment #5 from Martin Sebor  ---
A bigger patch that addresses a number of overflow-related problems has been
posted for review:
https://gcc.gnu.org/ml/gcc-patches/2016-12/msg00262.html

[Bug tree-optimization/78608] gimple-ssa-sprintf.c:570:17: runtime error: negation of -9223372036854775808 cannot be represented in type 'long int'

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78608

--- Comment #4 from Markus Trippelsdorf  ---
The patch fixes all issue that I came across.
Please apply your patch.
Thanks.

[Bug tree-optimization/78608] gimple-ssa-sprintf.c:570:17: runtime error: negation of -9223372036854775808 cannot be represented in type 'long int'

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78608

--- Comment #3 from Martin Sebor  ---
I suspect the same problem should come up with a call to vsprintf.  The patch
below should handle this case but I haven't don't done a bootstrap-ubsan to
verify there are no others like it.

diff --git a/gcc/gimple-ssa-sprintf.c b/gcc/gimple-ssa-sprintf.c
index eceed3e..2b0781a 100644
--- a/gcc/gimple-ssa-sprintf.c
+++ b/gcc/gimple-ssa-sprintf.c
@@ -565,7 +565,13 @@ tree_digits (tree x, int base, bool plus, bool prefix)
   if (tree_fits_shwi_p (x))
{
  HOST_WIDE_INT i = tree_to_shwi (x);
- if (i < 0)
+ if (HOST_WIDE_INT_MIN == i)
+   {
+ /* Avoid undefined behavior due to negating a minimum.  */
+ absval = HOST_WIDE_INT_MAX;
+ res = 1;
+   }
+ else if (i < 0)
{
  absval = -i;
  res = 1;

[Bug tree-optimization/78608] gimple-ssa-sprintf.c:570:17: runtime error: negation of -9223372036854775808 cannot be represented in type 'long int'

[msebor at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78608

Martin Sebor  changed:

   What|Removed |Added

   Keywords||ice-on-invalid-code
 Status|NEW |ASSIGNED
   Assignee|unassigned at gcc dot gnu.org  |msebor at gcc dot 
gnu.org
  Known to fail||7.0

--- Comment #2 from Martin Sebor  ---
Thanks for the test case.  The code is invalid but GCC should handle it
gracefully.

[Bug tree-optimization/78608] gimple-ssa-sprintf.c:570:17: runtime error: negation of -9223372036854775808 cannot be represented in type 'long int'

[trippels at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78608

Markus Trippelsdorf  changed:

   What|Removed |Added

 Status|UNCONFIRMED |NEW
   Last reconfirmed||2016-12-01
 Ever confirmed|0   |1

--- Comment #1 from Markus Trippelsdorf  ---
 % echo 'void foo() { __builtin_snprintf(0, 0, "%ld"); }' | gcc -x c -c -O2 -o
/dev/null -
gimple-ssa-sprintf.c:570:17: runtime error: negation of -9223372036854775808
cannot be represented in type 'long int'; cast to an unsigned type to negate
this value to itself