get_range_query vs NULL argument

[Andrew Pinski <pinskia@gmail.com>]

Hi,
  While fixing PR 108354, I came across that
ssa_name_has_boolean_range calls get_range_query with cfun as the
argument but sometimes while in IPA passes cfun is currently nullptr.
The question should we check the argument before calling
get_range_query or is it a valid thing to call it with a nullptr (and
have it return global_ranges in that case)?

I committed the patch (for PR 108354) with the workaround around the
issue via having the match.pd pattern which was calling
ssa_name_has_boolean_range only be invoked from the gimple
simplifiers.

Below is the patch which undones the workaround:
```
diff --git a/gcc/match.pd b/gcc/match.pd
index e7b700349a6..e352bd422f5 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -1732,7 +1732,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
  (if (!FIXED_POINT_TYPE_P (type))
  (plus @0 (negate @1))))

-#if GIMPLE
 /* 1 - a is a ^ 1 if a had a bool range. */
 /* This is only enabled for gimple as sometimes
    cfun is not set for the function which contains
@@ -1743,7 +1742,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   (if (INTEGRAL_TYPE_P (type)
        && ssa_name_has_boolean_range (@1))
    (bit_xor @1 @0)))
-#endif

 /* Other simplifications of negation (c.f. fold_negate_expr_1).  */
 (simplify
```
Note I can only so far reproduce the call to
ssa_name_has_boolean_range that causes an issue while building Ada
tools (while bootstrapping) because the code that needs to hit this is
related to variable sized type accesses.

Thanks,
Andrew Pinski