* common.opt: Split up -fisolate-erroneous-paths into

	-fisolate-erroneous-paths-dereference and
	-fisolate-erroneous-paths-attribute.
	* invoke.texi: Corresponding changes.
	* gimple.c (infer_nonnull_range):  Add and use new arguments
	to control what kind of statements can be used to infer a
	non-null range.
	* gimple.h (infer_nonnull_range): Update prototype.
	* tree-vrp.c (infer_value_range): Corresponding changes.
	* opts.c (default_options_table): Update due to option split.
	* gimple-ssa-isolate-paths.c: Fix trailing whitespace.
	(find_implicit_erroneous_behaviour): Pass additional arguments
	to infer_nonnull_range.
	(find_explicit_erroneous_behaviour): Similarly.
	(gate_isolate_erroneous_paths): Check both of the new
	options.

testsuite/

	* gcc.dg/pr38984.c: Use -fno-isolate-erroneous-paths-dereference.
	* gcc.dg/tree-ssa/isolate-2.c: Explicitly turn on
	-fisolate-erroneous-paths-attribute.
	* gcc.dg/tree-ssa/isolate-4.c: Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@205689 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 15 insertions, 6 deletions

diff --git a/gcc/gimple.c b/gcc/gimple.c
index 7bc87bc34ee..f11362a6b16 100644
--- a/gcc/gimple.c
+++ b/gcc/gimple.c
@@ -2502,10 +2502,16 @@ check_loadstore (gimple stmt ATTRIBUTE_UNUSED, tree op, void *data)
   return false;
 }
 
-/* If OP can be inferred to be non-zero after STMT executes, return true.  */
+/* If OP can be inferred to be non-NULL after STMT executes, return true.
+
+   DEREFERENCE is TRUE if we can use a pointer dereference to infer a
+   non-NULL range, FALSE otherwise.
+
+   ATTRIBUTE is TRUE if we can use attributes to infer a non-NULL range
+   for function arguments and return values.  FALSE otherwise.  */
 
 bool
-infer_nonnull_range (gimple stmt, tree op)
+infer_nonnull_range (gimple stmt, tree op, bool dereference, bool attribute)
 {
   /* We can only assume that a pointer dereference will yield
      non-NULL if -fdelete-null-pointer-checks is enabled.  */
@@ -2514,11 +2520,13 @@ infer_nonnull_range (gimple stmt, tree op)
       || gimple_code (stmt) == GIMPLE_ASM)
     return false;
 
-  if (walk_stmt_load_store_ops (stmt, (void *)op,
-				check_loadstore, check_loadstore))
+  if (dereference
+      && walk_stmt_load_store_ops (stmt, (void *)op,
+				   check_loadstore, check_loadstore))
     return true;
 
-  if (is_gimple_call (stmt) && !gimple_call_internal_p (stmt))
+  if (attribute
+      && is_gimple_call (stmt) && !gimple_call_internal_p (stmt))
     {
       tree fntype = gimple_call_fntype (stmt);
       tree attrs = TYPE_ATTRIBUTES (fntype);
@@ -2557,7 +2565,8 @@ infer_nonnull_range (gimple stmt, tree op)
 
   /* If this function is marked as returning non-null, then we can
      infer OP is non-null if it is used in the return statement.  */
-  if (gimple_code (stmt) == GIMPLE_RETURN
+  if (attribute
+      && gimple_code (stmt) == GIMPLE_RETURN
       && gimple_return_retval (stmt)
       && operand_equal_p (gimple_return_retval (stmt), op, 0)
       && lookup_attribute ("returns_nonnull",