[PATCH 1/2] vec: Add array_slice constructors from non-const and gc vectors

[Martin Jambor <mjambor@suse.cz>]

Hi,

This patch adds constructors of array_slice that are required to
create them from non-const (heap or auto) vectors or from GC vectors.

The use of non-const array_slices is somewhat limited, as creating one
from const vec<some_type> still leads to array_slice<const some_type>,
so I eventually also only resorted to having read-only array_slices.
But I do need the constructor from the gc vector.

Bootstrapped and tested along code that actually uses it on
x86_64-linux.  OK for trunk?

Thanks,

Martin


gcc/ChangeLog:

2022-08-08  Martin Jambor  <mjambor@suse.cz>

	* vec.h (array_slice): Add constructors for non-const reference to
	heap vector and pointers to heap vectors.
---
 gcc/vec.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/gcc/vec.h b/gcc/vec.h
index eed075addc9..b0477e1044c 100644
--- a/gcc/vec.h
+++ b/gcc/vec.h
@@ -2264,6 +2264,18 @@ public:
   array_slice (const vec<OtherT> &v)
     : m_base (v.address ()), m_size (v.length ()) {}
 
+  template<typename OtherT>
+  array_slice (vec<OtherT> &v)
+    : m_base (v.address ()), m_size (v.length ()) {}
+
+  template<typename OtherT>
+  array_slice (const vec<OtherT, va_gc> *v)
+    : m_base (v ? v->address () : nullptr), m_size (v ? v->length () : 0) {}
+
+  template<typename OtherT>
+  array_slice (vec<OtherT, va_gc> *v)
+    : m_base (v ? v->address () : nullptr), m_size (v ? v->length () : 0) {}
+
   iterator begin () { return m_base; }
   iterator end () { return m_base + m_size; }
 
-- 
2.37.2