* 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, 13 insertions, 6 deletions

diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index b30e889764d..704d4744dfd 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -378,7 +378,7 @@ Objective-C and Objective-C++ Dialects}.
 -fira-region=@var{region} -fira-hoist-pressure @gol
 -fira-loop-pressure -fno-ira-share-save-slots @gol
 -fno-ira-share-spill-slots -fira-verbose=@var{n} @gol
--fisolate-erroneous-paths
+-fisolate-erroneous-paths-dereference -fisolate-erroneous-paths-attribute
 -fivopts -fkeep-inline-functions -fkeep-static-consts -flive-range-shrinkage @gol
 -floop-block -floop-interchange -floop-strip-mine -floop-nest-optimize @gol
 -floop-parallelize-all -flto -flto-compression-level @gol
@@ -6848,7 +6848,7 @@ also turns on the following optimization flags:
 -finline-small-functions @gol
 -findirect-inlining @gol
 -fipa-sra @gol
--fisolate-erroneous-paths @gol
+-fisolate-erroneous-paths-dereference @gol
 -foptimize-sibling-calls @gol
 -fpartial-inlining @gol
 -fpeephole2 @gol
@@ -7742,10 +7742,17 @@ it may significantly increase code size
 (see @option{--param ipcp-unit-growth=@var{value}}).
 This flag is enabled by default at @option{-O3}.
 
-@item -fisolate-erroneous-paths
-Detect paths which trigger erroneous or undefined behaviour.  Isolate those
-paths from the main control flow and turn the statement with erroneous or
-undefined behaviour into a trap.
+@item -fisolate-erroneous-paths-dereference
+Detect paths which trigger erroneous or undefined behaviour due to
+dereferencing a NULL pointer.  Isolate those paths from the main control
+flow and turn the statement with erroneous or undefined behaviour into a trap.
+
+@item -fisolate-erroneous-paths-attribute
+Detect paths which trigger erroneous or undefined behaviour due a NULL value
+being used in a way which is forbidden by a @code{returns_nonnull} or @code{nonnull}
+attribute.  Isolate those paths from the main control flow and turn the
+statement with erroneous or undefined behaviour into a trap.  This is not
+currently enabled, but may be enabled by @code{-O2} in the future.
 
 @item -ftree-sink
 @opindex ftree-sink