re PR tree-optimization/51692 (ICE on several valgrind tests)

2012-01-03  Richard Guenther  <rguenther@suse.de>

	PR tree-optimization/51692
	* tree-ssa-dce.c (eliminate_unnecessary_stmts): Do not remove
	the LHS of allocation stmts.

	* gcc.dg/torture/pr51692.c: New testcase.

From-SVN: r182838

4 files changed, 53 insertions, 22 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index dd3c6d7..77e96a3 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2012-01-03  Richard Guenther  <rguenther@suse.de>
+
+	PR tree-optimization/51692
+	* tree-ssa-dce.c (eliminate_unnecessary_stmts): Do not remove
+	the LHS of allocation stmts.
+
 2012-01-03  Olivier Hainque  <hainque@adacore.com>
 
 	* system.h: Prior to #define, #undef fopen and freopen unconditionally.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6185d58..195630c 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,10 @@
 2012-01-03  Richard Guenther  <rguenther@suse.de>
 
+	PR tree-optimization/51692
+	* gcc.dg/torture/pr51692.c: New testcase.
+
+2012-01-03  Richard Guenther  <rguenther@suse.de>
+
 	PR debug/51650
 	* g++.dg/lto/pr51650-3_0.C: New testcase.
 
diff --git a/gcc/testsuite/gcc.dg/torture/pr51692.c b/gcc/testsuite/gcc.dg/torture/pr51692.c
new file mode 100644
index 0000000..34a81c2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr51692.c
@@ -0,0 +1,13 @@
+/* { dg-do compile } */
+
+int
+main ()
+{
+  volatile double d = 0.0;
+  double *p = __builtin_calloc (1, sizeof (double));
+  d += 1.0;
+  *p += 2.0;
+  __builtin_free (p);
+  return 0;
+}
+
diff --git a/gcc/tree-ssa-dce.c b/gcc/tree-ssa-dce.c
index a710de6..ccdf14a 100644
--- a/gcc/tree-ssa-dce.c
+++ b/gcc/tree-ssa-dce.c
@@ -1329,31 +1329,38 @@ eliminate_unnecessary_stmts (void)
 	    }
 	  else if (is_gimple_call (stmt))
 	    {
-	      call = gimple_call_fndecl (stmt);
-	      if (call)
+	      tree name = gimple_call_lhs (stmt);
+
+	      notice_special_calls (stmt);
+
+	      /* When LHS of var = call (); is dead, simplify it into
+		 call (); saving one operand.  */
+	      if (name
+		  && TREE_CODE (name) == SSA_NAME
+		  && !TEST_BIT (processed, SSA_NAME_VERSION (name))
+		  /* Avoid doing so for allocation calls which we
+		     did not mark as necessary, it will confuse the
+		     special logic we apply to malloc/free pair removal.  */
+		  && (!(call = gimple_call_fndecl (stmt))
+		      || DECL_BUILT_IN_CLASS (call) != BUILT_IN_NORMAL
+		      || (DECL_FUNCTION_CODE (call) != BUILT_IN_MALLOC
+			  && DECL_FUNCTION_CODE (call) != BUILT_IN_CALLOC
+			  && DECL_FUNCTION_CODE (call) != BUILT_IN_ALLOCA
+			  && (DECL_FUNCTION_CODE (call)
+			      != BUILT_IN_ALLOCA_WITH_ALIGN))))
 		{
-		  tree name;
-
-		  /* When LHS of var = call (); is dead, simplify it into
-		     call (); saving one operand.  */
-		  name = gimple_call_lhs (stmt);
-		  if (name && TREE_CODE (name) == SSA_NAME
-		           && !TEST_BIT (processed, SSA_NAME_VERSION (name)))
+		  something_changed = true;
+		  if (dump_file && (dump_flags & TDF_DETAILS))
 		    {
-		      something_changed = true;
-		      if (dump_file && (dump_flags & TDF_DETAILS))
-			{
-			  fprintf (dump_file, "Deleting LHS of call: ");
-			  print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
-			  fprintf (dump_file, "\n");
-			}
-
-		      gimple_call_set_lhs (stmt, NULL_TREE);
-		      maybe_clean_or_replace_eh_stmt (stmt, stmt);
-		      update_stmt (stmt);
-		      release_ssa_name (name);
+		      fprintf (dump_file, "Deleting LHS of call: ");
+		      print_gimple_stmt (dump_file, stmt, 0, TDF_SLIM);
+		      fprintf (dump_file, "\n");
 		    }
-		  notice_special_calls (stmt);
+
+		  gimple_call_set_lhs (stmt, NULL_TREE);
+		  maybe_clean_or_replace_eh_stmt (stmt, stmt);
+		  update_stmt (stmt);
+		  release_ssa_name (name);
 		}
 	    }
 	}