Remove remaining traces of m_vecdata from comments [PR109006]

The following patch adjusts remaining references to the removed m_vecdata
array from vec.h in various comments.

2023-03-04  Jakub Jelinek  <jakub@redhat.com>

	PR middle-end/109006
	* vec.cc (test_auto_alias): Adjust comment for removal of
	m_vecdata.
	* read-rtl-function.cc (function_reader::parse_block): Likewise.
	* gdbhooks.py: Likewise.

gcc/gdbhooks.py

@@ -133,10 +133,10 @@ vector: attempting to do so instead gives you the vec itself (for vec[0]),
 or a (probably) invalid cast to vec<> for the memory after the vec (for
 vec[1] onwards).
 
-Instead (for now) you must access m_vecdata:
-  (gdb) p bb->preds->m_vecdata[0]
+Instead (for now) you must access the payload directly:
+  (gdb) p ((edge_def**)(bb->preds+1))[0]
   $20 = <edge 0x7ffff044d380 (3 -> 5)>
-  (gdb) p bb->preds->m_vecdata[1]
+  (gdb) p ((edge_def**)(bb->preds+1))[1]
   $21 = <edge 0x7ffff044d3b8 (4 -> 5)>
 """
 import os.path

gcc/read-rtl-function.cc

@@ -622,10 +622,11 @@ function_reader::parse_block ()
 
      These can get out-of-sync when basic blocks are optimized away.
      They get back in sync by "compact_blocks".
-     We reconstruct cfun->cfg->x_basic_block_info->m_vecdata with NULL
-     values in it for any missing basic blocks, so that (a) == (b) for
-     all of the blocks we create.  The doubly-linked list of basic
-     blocks (next_bb/prev_bb) skips over these "holes".  */
+     We reconstruct cfun->cfg->x_basic_block_info->address () pointed
+     vector elements with NULL values in it for any missing basic blocks,
+     so that (a) == (b) for all of the blocks we create.  The
+     doubly-linked list of basic blocks (next_bb/prev_bb) skips over
+     these "holes".  */
 
   if (m_highest_bb_idx < bb_idx)
     m_highest_bb_idx = bb_idx;

gcc/vec.cc

@@ -568,7 +568,7 @@ test_auto_delete_vec ()
   ASSERT_EQ (dtor_count, 2);
 }
 
-/* Verify accesses to m_vecdata are done indirectly.  */
+/* Verify accesses to vector elements are done indirectly.  */
 
 static void
 test_auto_alias ()