Patchwork Add update-ssa verification code

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Submitter Richard Guenther
Date Aug. 14, 2012, 9:29 a.m.
Message ID <alpine.LNX.2.00.1208141127590.28649@zhemvz.fhfr.qr>
Download mbox | patch
Permalink /patch/177194/
State New
Headers show

Comments

Richard Guenther - Aug. 14, 2012, 9:29 a.m.
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  <rguenther@suse.de>

	* tree-into-ssa.c (update_ssa): Verify we do not rename
	symbols that are already partly in SSA form.

Patch

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
     {