Introduce vNULL to use as a nil initializer for vec<>.

This patch implements Jakub's idea of adding an empty struct with
a typecast operator that returns nil vectors.  This is useful to
shorten all the initializers when declaring vec instances or passing
nil vectors as function arguments.

2012-11-20  Diego Novillo  <dnovillo@google.com>
	    Jakub Jelinek  <jakub@redhat.com>

ChangeLog
	* vec.h (struct vnull): Declare.
	(vNULL): Declare.
	* vec.c (vNULL): Define.
	* bb-reorder.c: Replace all vec<T, A>() initializers with vNULL.
	* cfgexpand.c: Likewise.
	* cfgloop.c: Likewise.
	* cfgloopanal.c: Likewise.
	* cfgloopmanip.c: Likewise.
	* cgraph.c: Likewise.
	* config/c6x/c6x.c: Likewise.
	* config/i386/i386.c: Likewise.
	* df-core.c: Likewise.
	* dominance.c: Likewise.
	* dwarf2out.c: Likewise.
	* except.c: Likewise.
	* function.c: Likewise.
	* gcse.c: Likewise.
	* genautomata.c: Likewise.
	* graphds.c: Likewise.
	* graphite-scop-detection.c: Likewise.
	* graphite.c: Likewise.
	* haifa-sched.c: Likewise.
	* ifcvt.c: Likewise.
	* ipa-cp.c: Likewise.
	* ipa-inline-analysis.c: Likewise.
	* ipa-inline-transform.c: Likewise.
	* ipa-inline.c: Likewise.
	* ipa-prop.c: Likewise.
	* ipa-split.c: Likewise.
	* ipa-utils.c: Likewise.
	* ira-build.c: Likewise.
	* lto-cgraph.c: Likewise.
	* lto-streamer-in.c: Likewise.
	* lto-symtab.c: Likewise.
	* opts-global.c: Likewise.
	* passes.c: Likewise.
	* ree.c: Likewise.
	* sched-deps.c: Likewise.
	* sel-sched-ir.c: Likewise.
	* sel-sched-ir.h: Likewise.
	* sel-sched.c: Likewise.
	* stor-layout.c: Likewise.
	* trans-mem.c: Likewise.
	* tree-call-cdce.c: Likewise.
	* tree-cfg.c: Likewise.
	* tree-data-ref.c: Likewise.
	* tree-diagnostic.c: Likewise.
	* tree-eh.c: Likewise.
	* tree-loop-distribution.c: Likewise.
	* tree-predcom.c: Likewise.
	* tree-ssa-loop-im.c: Likewise.
	* tree-ssa-loop-ivcanon.c: Likewise.
	* tree-ssa-loop-manip.c: Likewise.
	* tree-ssa-loop-niter.c: Likewise.
	* tree-ssa-loop-prefetch.c: Likewise.
	* tree-ssa-math-opts.c: Likewise.
	* tree-ssa-phiopt.c: Likewise.
	* tree-ssa-pre.c: Likewise.
	* tree-ssa-propagate.c: Likewise.
	* tree-ssa-reassoc.c: Likewise.
	* tree-ssa-sccvn.c: Likewise.
	* tree-ssa-structalias.c: Likewise.
	* tree-ssa-threadedge.c: Likewise.
	* tree-ssa-uninit.c: Likewise.
	* tree-stdarg.c: Likewise.
	* tree-switch-conversion.c: Likewise.
	* tree-vect-data-refs.c: Likewise.
	* tree-vect-loop.c: Likewise.
	* tree-vect-slp.c: Likewise.
	* tree-vect-stmts.c: Likewise.
	* value-prof.c: Likewise.
	* varasm.c: Likewise.

ada/ChangeLog
	* gcc-interface/decl.c: Replace all vec<T,A>()
	initializers with vNULL.

cp/ChangeLog
	* name-lookup.c: Replace all vec<T, A>() initializers
	with vNULL.
	* semantics.c: Likewise.

fortran/ChangeLog
	* trans-openmp.c: Replace all vec<T, A>() initializers
	with vNULL.

lto/ChangeLog
	* lto.c: Replace all vec<T, A>() initializers with vNULL.

objc/ChangeLog
	* objc-act.c: Replace all vec<T, A>() initializers with vNULL.

Co-Authored-By: Jakub Jelinek <jakub@redhat.com>

From-SVN: r193677

1 files changed, 11 insertions, 11 deletions

diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
index ed89a5a..a7f0f9a 100644
--- a/gcc/tree-ssa-sccvn.c
+++ b/gcc/tree-ssa-sccvn.c
@@ -1027,7 +1027,7 @@ copy_reference_ops_from_call (gimple call,
 static vec<vn_reference_op_s> 
 create_reference_ops_from_ref (tree ref)
 {
-  vec<vn_reference_op_s> result = vec<vn_reference_op_s>();
+  vec<vn_reference_op_s> result = vNULL;
 
   copy_reference_ops_from_ref (ref, &result);
   return result;
@@ -1039,7 +1039,7 @@ create_reference_ops_from_ref (tree ref)
 static vec<vn_reference_op_s> 
 create_reference_ops_from_call (gimple call)
 {
-  vec<vn_reference_op_s> result = vec<vn_reference_op_s>();
+  vec<vn_reference_op_s> result = vNULL;
 
   copy_reference_ops_from_call (call, &result);
   return result;
@@ -1316,7 +1316,7 @@ static vec<vn_reference_op_s>
 valueize_shared_reference_ops_from_ref (tree ref, bool *valueized_anything)
 {
   if (!ref)
-    return vec<vn_reference_op_s>();
+    return vNULL;
   shared_lookup_references.truncate (0);
   copy_reference_ops_from_ref (ref, &shared_lookup_references);
   shared_lookup_references = valueize_refs_1 (shared_lookup_references,
@@ -1332,7 +1332,7 @@ static vec<vn_reference_op_s>
 valueize_shared_reference_ops_from_call (gimple call)
 {
   if (!call)
-    return vec<vn_reference_op_s>();
+    return vNULL;
   shared_lookup_references.truncate (0);
   copy_reference_ops_from_call (call, &shared_lookup_references);
   shared_lookup_references = valueize_refs (shared_lookup_references);
@@ -1452,7 +1452,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
   tree base;
   HOST_WIDE_INT offset, maxsize;
   static vec<vn_reference_op_s>
-    lhs_ops = vec<vn_reference_op_s>();
+    lhs_ops = vNULL;
   ao_ref lhs_ref;
   bool lhs_ref_ok = false;
 
@@ -1658,7 +1658,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
       HOST_WIDE_INT offset2, size2, maxsize2;
       int i, j;
       vec<vn_reference_op_s>
-	  rhs = vec<vn_reference_op_s>();
+	  rhs = vNULL;
       vn_reference_op_t vro;
       ao_ref r;
 
@@ -1715,7 +1715,7 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *vr_)
 	  vr->operands.safe_grow (i + 1 + rhs.length ());
 	  if (old == shared_lookup_references
 	      && vr->operands != old)
-	    shared_lookup_references = vec<vn_reference_op_s>();
+	    shared_lookup_references = vNULL;
 	}
       else
 	vr->operands.truncate (i + 1 + rhs.length ());
@@ -2507,7 +2507,7 @@ vn_phi_insert (gimple phi, tree result)
   void **slot;
   vn_phi_t vp1 = (vn_phi_t) pool_alloc (current_info->phis_pool);
   unsigned i;
-  vec<tree> args = vec<tree>();
+  vec<tree> args = vNULL;
 
   /* Canonicalize the SSA_NAME's to their value number.  */
   for (i = 0; i < gimple_phi_num_args (phi); i++)
@@ -3672,7 +3672,7 @@ process_scc (vec<tree> scc)
 static bool
 extract_and_process_scc_for_name (tree name)
 {
-  vec<tree> scc = vec<tree>();
+  vec<tree> scc = vNULL;
   tree x;
 
   /* Found an SCC, pop the components off the SCC stack and
@@ -3721,8 +3721,8 @@ extract_and_process_scc_for_name (tree name)
 static bool
 DFS (tree name)
 {
-  vec<ssa_op_iter> itervec = vec<ssa_op_iter>();
-  vec<tree> namevec = vec<tree>();
+  vec<ssa_op_iter> itervec = vNULL;
+  vec<tree> namevec = vNULL;
   use_operand_p usep = NULL;
   gimple defstmt;
   tree use;