This adds verification code that we do not try to rewrite a symbol
into SSA form that is already partly in SSA form. That would lead
to silent wrong-code generation.
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2012-08-14 Richard Guenther <rguent...@suse.de>
* tree-into-ssa.c (update_ssa): Verify we do not rename
symbols that are already partly in SSA form.
Index: gcc/tree-into-ssa.c
===================================================================
--- gcc/tree-into-ssa.c (revision 190346)
+++ gcc/tree-into-ssa.c (working copy)
@@ -3247,6 +3247,30 @@ update_ssa (unsigned update_flags)
statements and set local live-in information for the PHI
placement heuristics. */
prepare_block_for_update (start_bb, insert_phi_p);
+
+#ifdef ENABLE_CHECKING
+ for (i = 1; i < num_ssa_names; ++i)
+ {
+ tree name = ssa_name (i);
+ if (!name
+ || virtual_operand_p (name))
+ continue;
+
+ /* For all but virtual operands, which do not have SSA names
+ with overlapping life ranges, ensure that symbols marked
+ for renaming do not have existing SSA names associated with
+ them as we do not re-write them out-of-SSA before going
+ into SSA for the remaining symbol uses. */
+ if (marked_for_renaming (SSA_NAME_VAR (name)))
+ {
+ fprintf (stderr, "Existing SSA name for symbol marked for "
+ "renaming: ");
+ print_generic_expr (stderr, name, TDF_SLIM);
+ fprintf (stderr, "\n");
+ internal_error ("SSA corruption");
+ }
+ }
+#endif
}
else
{
