[PATCH] lower-bitint: Add debugging dump of SSA_NAME -> decl mappings

[Jakub Jelinek]

Hi!

While the SSA coalescing performed by lower bitint prints some information
if -fdump-tree-bitintlower-details, it is really hard to read and doesn't
contain the most important information which one looks for when debugging
bitint lowering issues, namely what VAR_DECLs (or PARM_DECLs/RESULT_DECLs)
each SSA_NAME in large_huge.m_names bitmap maps to.

So, the following patch adds dumping of that, so that we know that say
_3 -> bitint.3
_8 -> bitint.7
_16 -> bitint.7
etc.

Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?

2024-01-27  Jakub Jelinek  <ja...@redhat.com>

        * gimple-lower-bitint.cc (gimple_lower_bitint): For
        TDF_DETAILS dump mapping of SSA_NAMEs to decls.

--- gcc/gimple-lower-bitint.cc.jj       2024-01-26 00:07:35.629797857 +0100
+++ gcc/gimple-lower-bitint.cc  2024-01-26 17:40:29.083814064 +0100
@@ -6344,22 +6344,33 @@ gimple_lower_bitint (void)
              }
          }
       tree atype = NULL_TREE;
+      if (dump_file && (dump_flags & TDF_DETAILS))
+       fprintf (dump_file, "Mapping SSA_NAMEs to decls:\n");
       EXECUTE_IF_SET_IN_BITMAP (large_huge.m_names, 0, i, bi)
        {
          tree s = ssa_name (i);
          int p = var_to_partition (large_huge.m_map, s);
-         if (large_huge.m_vars[p] != NULL_TREE)
-           continue;
-         if (atype == NULL_TREE
-             || !tree_int_cst_equal (TYPE_SIZE (atype),
-                                     TYPE_SIZE (TREE_TYPE (s))))
+         if (large_huge.m_vars[p] == NULL_TREE)
            {
-             unsigned HOST_WIDE_INT nelts
-               = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (s))) / limb_prec;
-             atype = build_array_type_nelts (large_huge.m_limb_type, nelts);
+             if (atype == NULL_TREE
+                 || !tree_int_cst_equal (TYPE_SIZE (atype),
+                                         TYPE_SIZE (TREE_TYPE (s))))
+               {
+                 unsigned HOST_WIDE_INT nelts
+                   = tree_to_uhwi (TYPE_SIZE (TREE_TYPE (s))) / limb_prec;
+                 atype = build_array_type_nelts (large_huge.m_limb_type,
+                                                 nelts);
+               }
+             large_huge.m_vars[p] = create_tmp_var (atype, "bitint");
+             mark_addressable (large_huge.m_vars[p]);
+           }
+         if (dump_file && (dump_flags & TDF_DETAILS))
+           {
+             print_generic_expr (dump_file, s, TDF_SLIM);
+             fprintf (dump_file, " -> ");
+             print_generic_expr (dump_file, large_huge.m_vars[p], TDF_SLIM);
+             fprintf (dump_file, "\n");
            }
-         large_huge.m_vars[p] = create_tmp_var (atype, "bitint");
-         mark_addressable (large_huge.m_vars[p]);
        }
     }
 

        Jakub