inter-procedural value range propagation

inter-procedural value range propagation

implement very basic propapgation of return value ranges from VRP
pass.  This helps std::vector's push_back since we work out value range of
allocated block.  This propagates only within single translation unit.  I hoped
we will also do the propagation at WPA stage, but that needs more work on
ipa-cp side.

I also added code auto-detecting return_nonnull and corresponding -Wsuggest-attribute.

gcc/ChangeLog:

	* cgraph.cc (add_detected_attribute_1): New function.
	(cgraph_node::add_detected_attribute): Likewise.
	* cgraph.h (cgraph_node::add_detected_attribute): Declare.
	* common.opt: Add -Wsuggest-attribute=returns_nonnull.
	* doc/invoke.texi: Document new flag.
	* gimple-range-fold.cc (fold_using_range::range_of_call):
	Use known reutrn value ranges.
	* ipa-prop.cc (struct ipa_return_value_summary): New type.
	(class ipa_return_value_sum_t): New type.
	(ipa_return_value_sum): New summary.
	(ipa_record_return_value_range): New function.
	(ipa_return_value_range): New function.
	* ipa-prop.h (ipa_return_value_range): Declare.
	(ipa_record_return_value_range): Declare.
	* ipa-pure-const.cc (warn_function_returns_nonnull): New funcion.
	* ipa-utils.h (warn_function_returns_nonnull): Declare.
	* symbol-summary.h: Fix comment.
	* tree-vrp.cc (execute_ranger_vrp): Record return values.

gcc/testsuite/ChangeLog:

	* g++.dg/ipa/devirt-2.C: Add noipa attribute to prevent ipa-vrp.
	* g++.dg/ipa/devirt-7.C: Disable ipa-vrp.
	* g++.dg/ipa/ipa-icf-2.C: Disable ipa-vrp.
	* g++.dg/ipa/ipa-icf-3.C: Disable ipa-vrp.
	* g++.dg/ipa/ivinline-1.C: Disable ipa-vrp.
	* g++.dg/ipa/ivinline-3.C: Disable ipa-vrp.
	* g++.dg/ipa/ivinline-5.C: Disable ipa-vrp.
	* g++.dg/ipa/ivinline-8.C: Disable ipa-vrp.
	* g++.dg/ipa/nothrow-1.C: Disable ipa-vrp.
	* g++.dg/ipa/pure-const-1.C: Disable ipa-vrp.
	* g++.dg/ipa/pure-const-2.C: Disable ipa-vrp.
	* g++.dg/lto/inline-crossmodule-1_0.C: Disable ipa-vrp.
	* gcc.c-torture/compile/pr106433.c: Add noipa attribute to prevent ipa-vrp.
	* gcc.c-torture/execute/frame-address.c: Likewise.
	* gcc.dg/vla-1.c: Add noipa attribute to prevent ipa-vrp.
	* gcc.dg/ipa/fopt-info-inline-1.c: Disable ipa-vrp.
	* gcc.dg/ipa/ipa-icf-25.c: Disable ipa-vrp.
	* gcc.dg/ipa/ipa-icf-38.c: Disable ipa-vrp.
	* gcc.dg/ipa/pure-const-1.c: Disable ipa-vrp.
	* gcc.dg/ipa/remref-0.c: Add noipa attribute to prevent ipa-vrp.
	* gcc.dg/tree-prof/time-profiler-1.c: Disable ipa-vrp.
	* gcc.dg/tree-prof/time-profiler-2.c: Disable ipa-vrp.
	* gcc.dg/tree-ssa/pr110269.c: Disable ipa-vrp.
	* gcc.dg/tree-ssa/pr20701.c: Disable ipa-vrp.
	* gcc.dg/tree-ssa/vrp05.c: Disable ipa-vrp.
	* gcc.dg/tree-ssa/return-value-range-1.c: New test.