re PR middle-end/86505 (__builtin_va_arg_pack_len() computes the number of arguments wrongly)

2018-08-17  Richard Biener  <rguenther@suse.de>

	PR middle-end/86505
	* tree-inline.c (copy_bb): When inlining __builtin_va_arg_pack_len ()
	across a va-arg-pack using call adjust its return value accordingly.

	* gcc.dg/torture/pr86505.c: New testcase.

From-SVN: r263613

gcc/ChangeLog

+2018-08-17  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/86505
+	* tree-inline.c (copy_bb): When inlining __builtin_va_arg_pack_len ()
+	across a va-arg-pack using call adjust its return value accordingly.
+
 2018-08-16  Martin Sebor  <msebor@redhat.com>
 
 	PR tree-optimization/86853

gcc/testsuite/ChangeLog

+2018-08-17  Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/86505
+	* gcc.dg/torture/pr86505.c: New testcase.
+
 2018-08-16  Martin Sebor  <msebor@redhat.com>
 
 	PR tree-optimization/86853

gcc/testsuite/gcc.dg/torture/pr86505.c

+/* { dg-do run } */
+
+static inline __attribute__(( __always_inline__)) int 
+funA(unsigned int param, ...) 
+{ 
+  return __builtin_va_arg_pack_len(); 
+}
+
+static inline __attribute__(( __always_inline__)) int
+funB(unsigned int param, ...)
+{ 
+  return funA(param,  2, 4, __builtin_va_arg_pack()); 
+}
+
+int 
+testBuiltin(void) 
+{ 
+  int rc = funB(0,1,2); 
+  if (rc != 4)
+    return 1;
+  return 0;
+}
+
+int
+main()
+{
+  int rc = testBuiltin();
+  if (rc == 1)
+    __builtin_abort ();
+
+  return 0;
+}

gcc/tree-inline.c

@@ -1940,8 +1940,7 @@ copy_bb (copy_body_data *id, basic_block bb,
 		   && id->call_stmt
 		   && (decl = gimple_call_fndecl (stmt))
 		   && DECL_BUILT_IN_CLASS (decl) == BUILT_IN_NORMAL
-		   && DECL_FUNCTION_CODE (decl) == BUILT_IN_VA_ARG_PACK_LEN
-		   && ! gimple_call_va_arg_pack_p (id->call_stmt))
+		   && DECL_FUNCTION_CODE (decl) == BUILT_IN_VA_ARG_PACK_LEN)
 	    {
 	      /* __builtin_va_arg_pack_len () should be replaced by
 		 the number of anonymous arguments.  */
@@ -1952,10 +1951,22 @@ copy_bb (copy_body_data *id, basic_block bb,
 	      for (p = DECL_ARGUMENTS (id->src_fn); p; p = DECL_CHAIN (p))
 		nargs--;
 
-	      count = build_int_cst (integer_type_node, nargs);
-	      new_stmt = gimple_build_assign (gimple_call_lhs (stmt), count);
-	      gsi_replace (&copy_gsi, new_stmt, false);
-	      stmt = new_stmt;
+	      if (!gimple_call_va_arg_pack_p (id->call_stmt))
+		{
+		  count = build_int_cst (integer_type_node, nargs);
+		  new_stmt = gimple_build_assign (gimple_call_lhs (stmt), count);
+		  gsi_replace (&copy_gsi, new_stmt, false);
+		  stmt = new_stmt;
+		}
+	      else if (nargs != 0)
+		{
+		  tree newlhs = create_tmp_reg_or_ssa_name (integer_type_node);
+		  count = build_int_cst (integer_type_node, nargs);
+		  new_stmt = gimple_build_assign (gimple_call_lhs (stmt),
+						  PLUS_EXPR, newlhs, count);
+		  gimple_call_set_lhs (stmt, newlhs);
+		  gsi_insert_after (&copy_gsi, new_stmt, GSI_NEW_STMT);
+		}
 	    }
 	  else if (call_stmt
 		   && id->call_stmt