https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109031
Roger Sayle <roger at nextmovesoftware dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
CC| |roger at nextmovesoftware dot
com
Assignee|unassigned at gcc dot gnu.org |roger at
nextmovesoftware dot com
Keywords| |patch
--- Comment #28 from Roger Sayle <roger at nextmovesoftware dot com> ---
Doh! My apologies for this breakage. I'm currently testing the following fix:
diff --git a/gcc/tree-chrec.cc b/gcc/tree-chrec.cc
index f93d8dc..2f67581 100644
--- a/gcc/tree-chrec.cc
+++ b/gcc/tree-chrec.cc
@@ -623,7 +623,9 @@ chrec_apply (unsigned var,
else if (operand_equal_p (CHREC_LEFT (chrec), chrecr)
&& TREE_CODE (x) == PLUS_EXPR
&& integer_all_onesp (TREE_OPERAND (x, 1))
- && !POINTER_TYPE_P (type))
+ && !POINTER_TYPE_P (type)
+ && TYPE_PRECISION (TREE_TYPE (x))
+ >= TYPE_PRECISION (type))
{
/* We know the number of iterations can't be negative.
So {a, +, a} (x-1) -> "a*x". */
The integer_all_onesp test is only equivalent to -1 when the TREE_TYPE (x)
is the same width or wider than type. In this case, TREE_TYPE (x) is unsigned
char and x is "zero+255", so performed in the wrong type (zero+255+1) becomes
zero instead of zero+256.
