https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107898
Andrew Macleod <amacleod at redhat dot com> changed:
What |Removed |Added
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CC| |amacleod at redhat dot com
--- Comment #3 from Andrew Macleod <amacleod at redhat dot com> ---
(In reply to Richard Biener from comment #1)
> I'm not sure why we have to require compatible ranges on intersection
> of irange though? Since we don't have anti-ranges there's no implicit
Its doesnt require compatible types, it requires compatible precisions. From
gimple-range-fold.h:
static inline bool
range_compatible_p (tree type1, tree type2)
{
// types_compatible_p requires conversion in both directions to be useless.
// GIMPLE only requires a cast one way in order to be compatible.
// Ranges really only need the sign and precision to be the same.
return (TYPE_PRECISION (type1) == TYPE_PRECISION (type2)
&& TYPE_SIGN (type1) == TYPE_SIGN (type2));
}
>
> Unfortunately there's no conversion operator or operator> for irange,
> we just want to ask if (r > max_size) (and have max_size converted to
> the type of r with saturation).
You can cast an irange to another type using range_cast. ie something like
diff --git a/gcc/gimple-ssa-warn-alloca.cc b/gcc/gimple-ssa-warn-alloca.cc
index 83a241a3a4b..0502c433f93 100644
--- a/gcc/gimple-ssa-warn-alloca.cc
+++ b/gcc/gimple-ssa-warn-alloca.cc
@@ -225,6 +225,8 @@ alloca_call_type (gimple *stmt, bool is_vla)
build_int_cst (size_type_node, max_size),
VR_ANTI_RANGE);
+ if (!types_compatible_p (r.type (), invalid_range.type ()))
+ range_cast (invalid_range, r.type ());
r.intersect (invalid_range);
if (r.undefined_p ())
return alloca_type_and_limit (ALLOCA_OK)
We decided to force something like this to be explicit by the caller rather
than make assumptions in intersect/union and silently do conversions. We've
caught a number of bugs along the way because of this.
Another option would be to simply create the invalid_range with the same type
upfront instead of assuming size_type_node. ie:
@@ -221,8 +221,8 @@ alloca_call_type (gimple *stmt, bool is_vla)
&& !r.varying_p ())
{
// The invalid bits are anything outside of [0, MAX_SIZE].
- int_range<2> invalid_range (build_int_cst (size_type_node, 0),
- build_int_cst (size_type_node, max_size),
+ int_range<2> invalid_range (build_int_cst (r.type (), 0),
+ build_int_cst (r.type (), max_size),
VR_ANTI_RANGE);
r.intersect (invalid_range);
As long as r.type () is irange::supports_p (r.type ())
