Introduce gimple_assign and use it in various places

This corresponds to:
  [PATCH 05/89] Introduce gimple_assign and use it in various places
  https://gcc.gnu.org/ml/gcc-patches/2014-04/msg01151.html
from the original 89-patch kit

That earlier patch was approved by Jeff:
> Similar to the gimple_cond patch. Update for the changes in the
> prerequisites and it's good to go. Please post final version for
> archival purposes.
in https://gcc.gnu.org/ml/gcc-patches/2014-05/msg00596.html

gcc/
	* coretypes.h (gimple_assign): New typedef.
	(const_gimple_assign): New typedef.

	* gimple.h (struct gimple_statement_assign): New subclass of
	gimple_statement_with_memory_ops, adding the invariant that
	stmt->code == GIMPLE_ASSIGN.
	(is_a_helper <gimple_statement_assign>::test): New.

	* gdbhooks.py (build_pretty_printer): Add gimple_assign and its
	variants, using the gimple printer.

	* gimple-builder.c (build_assign): Return a gimple_assign rather
	than just a gimple from each of the overloaded variants.
	(build_type_cast): Likewise.
	* gimple-builder.h (build_assign): Likewise.
	(build_type_cast): Likewise.
	* gimple.c (gimple_build_assign_stat): Likewise.
	(gimple_build_assign_with_ops): Likewise.
	* gimple.h (gimple_build_assign_stat): Likewise.
	(gimple_build_assign_with_ops): Likewise.

	* asan.c (get_mem_ref_of_assignment): Require a const_gimple_assign
	rather than just a "const gimple" (the latter is not a
	"const_gimple").
	* gimple-pretty-print.c (dump_unary_rhs): Require a gimple_assign
	rather than just a gimple.
	(dump_binary_rhs): Likewise.
	(dump_ternary_rhs): Likewise.
	* tree-cfg.c (verify_gimple_assign_unary): Likewise.
	(verify_gimple_assign_binary): Likewise.
	(verify_gimple_assign_ternary): Likewise.
	(verify_gimple_assign_single): Likewise.
	(verify_gimple_assign): Likewise.
	* tree-ssa-sccvn.c (simplify_unary_expression): Likewise.
	(try_to_simplify): Likewise.
	* tree-tailcall.c (process_assignment): Likewise.
	* tree-vect-generic.c (expand_vector_operation): Likewise.
	* tree-vrp.c (extract_range_from_cond_expr): Likewise.
	(extract_range_from_assignment): Likewise.

	* asan.c (has_stmt_been_instrumented_p): Add checked cast to
	gimple_assign in regions where a stmt is known to have code
	GIMPLE_ASSIGN.
	* gimple-pretty-print.c (pp_gimple_stmt_1): Likewise.
	* tree-cfg.c (verify_gimple_stmt): Likewise.
	* tree-ssa-sccvn.c (visit_use): Likewise.
	* tree-tailcall.c (find_tail_calls): Likewise.
	* tree-vrp.c (vrp_visit_assignment_or_call): Likewise.

	* tree-vrp.c (simplify_stmt_for_jump_threading): Replace a check
	against GIMPLE_ASSIGN with a dyn_cast<gimple_assign>, introducing
	a gimple_assign local.

	* tree-vect-generic.c (expand_vector_condition): Convert local to a
	gimple_assign, adding a checked cast when extracting from gsi, since
	this is only called when  underlying stmt has code GIMPLE_ASSIGN.
	(optimize_vector_constructor): Likewise.
	(lower_vec_perm): Likewise.
	(expand_vector_operations_1): Convert local to a gimple_assign,
	introducing a dyn_cast.

1 files changed, 7 insertions, 6 deletions

diff --git a/gcc/gimple.c b/gcc/gimple.c
index a75479a44a0..5ffa3570cf3 100644
--- a/gcc/gimple.c
+++ b/gcc/gimple.c
@@ -377,7 +377,7 @@ gimple_build_call_from_tree (tree t)
    LHS of the assignment.
    RHS of the assignment which can be unary or binary.  */
 
-gimple
+gimple_assign
 gimple_build_assign_stat (tree lhs, tree rhs MEM_STAT_DECL)
 {
   enum tree_code subcode;
@@ -393,19 +393,20 @@ gimple_build_assign_stat (tree lhs, tree rhs MEM_STAT_DECL)
    OP1 and OP2.  If OP2 is NULL then SUBCODE must be of class
    GIMPLE_UNARY_RHS or GIMPLE_SINGLE_RHS.  */
 
-gimple
+gimple_assign
 gimple_build_assign_with_ops (enum tree_code subcode, tree lhs, tree op1,
 			      tree op2, tree op3 MEM_STAT_DECL)
 {
   unsigned num_ops;
-  gimple p;
+  gimple_assign p;
 
   /* Need 1 operand for LHS and 1 or 2 for the RHS (depending on the
      code).  */
   num_ops = get_gimple_rhs_num_ops (subcode) + 1;
 
-  p = gimple_build_with_ops_stat (GIMPLE_ASSIGN, (unsigned)subcode, num_ops
-  			          PASS_MEM_STAT);
+  p = as_a <gimple_assign> (
+        gimple_build_with_ops_stat (GIMPLE_ASSIGN, (unsigned)subcode, num_ops
+				    PASS_MEM_STAT));
   gimple_assign_set_lhs (p, lhs);
   gimple_assign_set_rhs1 (p, op1);
   if (op2)
@@ -423,7 +424,7 @@ gimple_build_assign_with_ops (enum tree_code subcode, tree lhs, tree op1,
   return p;
 }
 
-gimple
+gimple_assign
 gimple_build_assign_with_ops (enum tree_code subcode, tree lhs, tree op1,
 			      tree op2 MEM_STAT_DECL)
 {