re PR c++/19476 (Missed null checking elimination with new)

2013-10-03  Marc Glisse  <marc.glisse@inria.fr>

	PR c++/19476
gcc/c-family/
	* c.opt (fcheck-new): Move to common.opt.

gcc/
	* common.opt (fcheck-new): Moved from c.opt. Make it 'Common'.
	* calls.c (alloca_call_p): Use get_callee_fndecl.
	* fold-const.c (tree_expr_nonzero_warnv_p): Handle operator new.
	* tree-vrp.c (gimple_stmt_nonzero_warnv_p, stmt_interesting_for_vrp):
	Likewise.
	(vrp_visit_stmt): Remove duplicated code.

gcc/testsuite/
	* g++.dg/tree-ssa/pr19476-1.C: New file.
	* g++.dg/tree-ssa/pr19476-2.C: Likewise.
	* g++.dg/tree-ssa/pr19476-3.C: Likewise.
	* g++.dg/tree-ssa/pr19476-4.C: Likewise.

From-SVN: r203163

gcc/ChangeLog

+2013-10-03  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR c++/19476
+	* common.opt (fcheck-new): Moved from c.opt. Make it 'Common'.
+	* calls.c (alloca_call_p): Use get_callee_fndecl.
+	* fold-const.c (tree_expr_nonzero_warnv_p): Handle operator new.
+	* tree-vrp.c (gimple_stmt_nonzero_warnv_p, stmt_interesting_for_vrp):
+	Likewise.
+	(vrp_visit_stmt): Remove duplicated code.
+
 2013-10-03  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	* config/rs6000/rs6000-builtin.def (XSRDPIM): Use floatdf2,

gcc/c-family/ChangeLog

+2013-10-03  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR c++/19476
+	* c.opt (fcheck-new): Move to common.opt.
+
 2013-09-25  Marek Polacek  <polacek@redhat.com>
 	    Jakub Jelinek  <jakub@redhat.com>
 

gcc/c-family/c.opt

@@ -855,10 +855,6 @@ fcilkplus
 C ObjC C++ ObjC++ LTO Report Var(flag_enable_cilkplus) Init(0)
 Enable Cilk Plus
 
-fcheck-new
-C++ ObjC++ Var(flag_check_new)
-Check the return value of new
-
 fcond-mismatch
 C ObjC C++ ObjC++
 Allow the arguments of the '?' operator to have different types

gcc/calls.c

@@ -635,11 +635,10 @@ gimple_alloca_call_p (const_gimple stmt)
 bool
 alloca_call_p (const_tree exp)
 {
+  tree fndecl;
   if (TREE_CODE (exp) == CALL_EXPR
-      && TREE_CODE (CALL_EXPR_FN (exp)) == ADDR_EXPR
-      && (TREE_CODE (TREE_OPERAND (CALL_EXPR_FN (exp), 0)) == FUNCTION_DECL)
-      && (special_function_p (TREE_OPERAND (CALL_EXPR_FN (exp), 0), 0)
-	  & ECF_MAY_BE_ALLOCA))
+      && (fndecl = get_callee_fndecl (exp))
+      && (special_function_p (fndecl, 0) & ECF_MAY_BE_ALLOCA))
     return true;
   return false;
 }

gcc/common.opt

@@ -913,6 +913,10 @@ fcheck-data-deps
 Common Report Var(flag_check_data_deps)
 Compare the results of several data dependence analyzers.
 
+fcheck-new
+Common Var(flag_check_new)
+Check the return value of new in C++
+
 fcombine-stack-adjustments
 Common Report Var(flag_combine_stack_adjustments) Optimization
 Looks for opportunities to reduce stack adjustments and stack references.

gcc/fold-const.c

@@ -16222,7 +16222,15 @@ tree_expr_nonzero_warnv_p (tree t, bool *strict_overflow_p)
 					strict_overflow_p);
 
     case CALL_EXPR:
-      return alloca_call_p (t);
+      {
+	tree fndecl = get_callee_fndecl (t);
+	if (!fndecl) return false;
+	if (flag_delete_null_pointer_checks && !flag_check_new
+	    && DECL_IS_OPERATOR_NEW (fndecl)
+	    && !TREE_NOTHROW (fndecl))
+	  return true;
+	return alloca_call_p (t);
+      }
 
     default:
       break;

gcc/testsuite/ChangeLog

+2013-10-03  Marc Glisse  <marc.glisse@inria.fr>
+
+	PR c++/19476
+	* g++.dg/tree-ssa/pr19476-1.C: New file.
+	* g++.dg/tree-ssa/pr19476-2.C: Likewise.
+	* g++.dg/tree-ssa/pr19476-3.C: Likewise.
+	* g++.dg/tree-ssa/pr19476-4.C: Likewise.
+
 2013-10-03  Michael Meissner  <meissner@linux.vnet.ibm.com>
 
 	* gcc.target/powerpc/p8vector-fp.c: New test for floating point

gcc/testsuite/g++.dg/tree-ssa/pr19476-1.C

+/* { dg-do compile } */
+/* { dg-options "-O -fdump-tree-ccp1" } */
+
+#include <new>
+
+int f(){
+  return 33 + (0 == new(std::nothrow) int);
+}
+int g(){
+  return 42 + (0 == new int[50]);
+}
+
+/* { dg-final { scan-tree-dump     "return 42" "ccp1" } } */
+/* { dg-final { scan-tree-dump-not "return 33" "ccp1" } } */
+/* { dg-final { cleanup-tree-dump "ccp1" } } */

gcc/testsuite/g++.dg/tree-ssa/pr19476-2.C

+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+#include <new>
+
+int f(){
+  int *p = new(std::nothrow) int;
+  return 33 + (0 == p);
+}
+int g(){
+  int *p = new int[50];
+  return 42 + (0 == p);
+}
+
+/* { dg-final { scan-tree-dump     "return 42" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "return 33" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/testsuite/g++.dg/tree-ssa/pr19476-3.C

+/* { dg-do compile } */
+/* { dg-options "-O3 -fcheck-new -fdump-tree-optimized" } */
+
+#include <new>
+
+int g(){
+  return 42 + (0 == new int);
+}
+
+/* { dg-final { scan-tree-dump-not "return 42" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/testsuite/g++.dg/tree-ssa/pr19476-4.C

+/* { dg-do compile } */
+/* { dg-options "-O3 -fno-delete-null-pointer-checks -fdump-tree-optimized" } */
+
+#include <new>
+
+int g(){
+  return 42 + (0 == new int);
+}
+
+/* { dg-final { scan-tree-dump-not "return 42" "optimized" } } */
+/* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/tree-vrp.c

@@ -1051,7 +1051,15 @@ gimple_stmt_nonzero_warnv_p (gimple stmt, bool *strict_overflow_p)
     case GIMPLE_ASSIGN:
       return gimple_assign_nonzero_warnv_p (stmt, strict_overflow_p);
     case GIMPLE_CALL:
-      return gimple_alloca_call_p (stmt);
+      {
+	tree fndecl = gimple_call_fndecl (stmt);
+	if (!fndecl) return false;
+	if (flag_delete_null_pointer_checks && !flag_check_new
+	    && DECL_IS_OPERATOR_NEW (fndecl)
+	    && !TREE_NOTHROW (fndecl))
+	  return true;
+	return gimple_alloca_call_p (stmt);
+      }
     default:
       gcc_unreachable ();
     }
@@ -6490,7 +6498,8 @@ stmt_interesting_for_vrp (gimple stmt)
 	      || POINTER_TYPE_P (TREE_TYPE (lhs)))
 	  && ((is_gimple_call (stmt)
 	       && gimple_call_fndecl (stmt) != NULL_TREE
-	       && DECL_BUILT_IN (gimple_call_fndecl (stmt)))
+	       && (DECL_BUILT_IN (gimple_call_fndecl (stmt))
+		   || DECL_IS_OPERATOR_NEW (gimple_call_fndecl (stmt))))
 	      || !gimple_vuse (stmt)))
 	return true;
     }
@@ -7411,16 +7420,7 @@ vrp_visit_stmt (gimple stmt, edge *taken_edge_p, tree *output_p)
   if (!stmt_interesting_for_vrp (stmt))
     gcc_assert (stmt_ends_bb_p (stmt));
   else if (is_gimple_assign (stmt) || is_gimple_call (stmt))
-    {
-      /* In general, assignments with virtual operands are not useful
-	 for deriving ranges, with the obvious exception of calls to
-	 builtin functions.  */
-      if ((is_gimple_call (stmt)
-	   && gimple_call_fndecl (stmt) != NULL_TREE
-	   && DECL_BUILT_IN (gimple_call_fndecl (stmt)))
-	  || !gimple_vuse (stmt))
-	return vrp_visit_assignment_or_call (stmt, output_p);
-    }
+    return vrp_visit_assignment_or_call (stmt, output_p);
   else if (gimple_code (stmt) == GIMPLE_COND)
     return vrp_visit_cond_stmt (stmt, taken_edge_p);
   else if (gimple_code (stmt) == GIMPLE_SWITCH)