analyzer: Bail out on function pointer for -Wanalyzer-allocation-size

On s390 pr94688.c is failing due to excess error

pr94688.c:6:5: warning: allocated buffer size is not a multiple of the pointee's size [CWE-131] [-Wanalyzer-allocation-size]

This is because on s390 functions are by default aligned to an 8-byte
boundary and during function type construction size is set to function
boundary.  Thus, for the assignment

a.0_1 = (void (*<T237>) ()) &a;

we have that the right-hand side is pointing to a 4-byte memory region
whereas the size of the function pointer is 8 byte and a warning is
emitted.

Since -Wanalyzer-allocation-size is not about pointers to code, bail out
early.

gcc/analyzer/ChangeLog:

	* region-model.cc (region_model::check_region_size): Bail out
	early on function pointers.

1 files changed, 4 insertions, 0 deletions

diff --git a/gcc/analyzer/region-model.cc b/gcc/analyzer/region-model.cc
index 665873d..bebe2ed 100644
--- a/gcc/analyzer/region-model.cc
+++ b/gcc/analyzer/region-model.cc
@@ -3514,6 +3514,10 @@ region_model::check_region_size (const region *lhs_reg, const svalue *rhs_sval,
       || TYPE_SIZE_UNIT (pointee_type) == NULL_TREE)
     return;
 
+  /* Bail out early on function pointers.  */
+  if (TREE_CODE (pointee_type) == FUNCTION_TYPE)
+    return;
+
   /* Bail out early on pointers to structs where we can
      not deduce whether the buffer size is compatible.  */
   bool is_struct = RECORD_OR_UNION_TYPE_P (pointee_type);