Hybrid EVRP and testcases

Hybrid EVRP and testcases

Provide a hybrid EVRP pass which uses legacy EVRP and adds additonal
enhancements from the new ranger infrastructure.
A New option is also provided, -fevrp-mode=
And adjust testcases

gcc/ChangeLog:

2020-10-06  Andrew MacLeod  <amacleod@redhat.com>

	* flag-types.h (enum evrp_mode): New enumerated type EVRP_MODE_*.
	* common.opt (fevrp-mode): New undocumented flag.
	* gimple-ssa-evrp.c: Include gimple-range.h
	(class rvrp_folder): EVRP folding using ranger exclusively.
	(rvrp_folder::rvrp_folder): New.
	(rvrp_folder::~rvrp_folder): New.
	(rvrp_folder::value_of_expr): New.  Use rangers value_of_expr.
	(rvrp_folder::value_on_edge): New.  Use rangers value_on_edge.
	(rvrp_folder::value_of_Stmt): New.  Use rangers value_of_stmt.
	(rvrp_folder::fold_stmt): New.  Call the simplifier.
	(class hybrid_folder): EVRP folding using both engines.
	(hybrid_folder::hybrid_folder): New.
	(hybrid_folder::~hybrid_folder): New.
	(hybrid_folder::fold_stmt): New.  Simplify with one engne, then the
	other.
	(hybrid_folder::value_of_expr): New.  Use both value routines.
	(hybrid_folder::value_on_edge): New.  Use both value routines.
	(hybrid_folder::value_of_stmt): New.  Use both value routines.
	(hybrid_folder::choose_value): New.  Choose between range_analzyer and
	rangers values.
	(execute_early_vrp): Choose a folder based on flag_evrp_mode.
	* vr-values.c (simplify_using_ranges::fold_cond): Try range_of_stmt
	first to see if it returns a value.
	(simplify_using_ranges::simplify_switch_using_ranges): Return true if
	any changes were made to the switch.

gcc/testsuite/ChangeLog:

2020-10-06  Andrew MacLeod  <amacleod@redhat.com>

	* gcc.dg/pr81192.c: Disable EVRP pass.
	* gcc.dg/tree-ssa/pr77445-2.c: Ditto.
	* gcc.dg/tree-ssa/ssa-dom-thread-6.c: Adjust.
	* gcc.dg/tree-ssa/ssa-dom-thread-7.c: Ditto.