re PR rtl-optimization/10776 (Large aggregate initializers with a single relocated entry causes excessive compile time regression)

        PR opt/10776
        * typeck2.c (split_nonconstant_init_1, split_nonconstant_init): New.
        (store_init_value): Use it.
        * decl.c (check_initializer): Expect full initialization code
        from store_init_value.
        * init.c (expand_aggr_init_1): Likewise.
        * decl2.c (maybe_emit_vtables): Abort if runtime init needed.

From-SVN: r75763

5 files changed, 131 insertions, 11 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 60e7192..941176d 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,13 @@
+2004-01-12  Richard Henderson  <rth@redhat.com>
+
+	PR opt/10776
+	* typeck2.c (split_nonconstant_init_1, split_nonconstant_init): New.
+	(store_init_value): Use it.
+	* decl.c (check_initializer): Expect full initialization code
+	from store_init_value.
+	* init.c (expand_aggr_init_1): Likewise.
+	* decl2.c (maybe_emit_vtables): Abort if runtime init needed.
+
 2004-01-12  Mark Mitchell  <mark@codesourcery.com>
 
 	* class.c (layout_class_type): For non-POD class types, also copy
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 3ce6d0a..9a83069 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -4395,6 +4395,7 @@ static tree
 check_initializer (tree decl, tree init, int flags, tree *cleanup)
 {
   tree type = TREE_TYPE (decl);
+  tree init_code = NULL;
 
   /* If `start_decl' didn't like having an initialization, ignore it now.  */
   if (init != NULL_TREE && DECL_INITIAL (decl) == NULL_TREE)
@@ -4511,7 +4512,10 @@ check_initializer (tree decl, tree init, int flags, tree *cleanup)
 	{
 	dont_use_constructor:
 	  if (TREE_CODE (init) != TREE_VEC)
-	    init = store_init_value (decl, init);
+	    {
+	      init_code = store_init_value (decl, init);
+	      init = NULL;
+	    }
 	}
     }
   else if (DECL_EXTERNAL (decl))
@@ -4534,9 +4538,9 @@ check_initializer (tree decl, tree init, int flags, tree *cleanup)
     check_for_uninitialized_const_var (decl);
 
   if (init && init != error_mark_node)
-    init = build (INIT_EXPR, type, decl, init);
+    init_code = build (INIT_EXPR, type, decl, init);
 
-  return init;
+  return init_code;
 }
 
 /* If DECL is not a local variable, give it RTL.  */
diff --git a/gcc/cp/decl2.c b/gcc/cp/decl2.c
index 4068826..ef8ea6e 100644
--- a/gcc/cp/decl2.c
+++ b/gcc/cp/decl2.c
@@ -1605,7 +1605,11 @@ maybe_emit_vtables (tree ctype)
 	cgraph_varpool_mark_needed_node (cgraph_varpool_node (vtbl));
 
       if (TREE_TYPE (DECL_INITIAL (vtbl)) == 0)
-	store_init_value (vtbl, DECL_INITIAL (vtbl));
+	{
+	  /* It had better be all done at compile-time.  */
+	  if (store_init_value (vtbl, DECL_INITIAL (vtbl)))
+	    abort ();
+	}
 
       if (write_symbols == DWARF_DEBUG || write_symbols == DWARF2_DEBUG)
 	{
diff --git a/gcc/cp/init.c b/gcc/cp/init.c
index f717fb2..1dc5d9d 100644
--- a/gcc/cp/init.c
+++ b/gcc/cp/init.c
@@ -1272,8 +1272,9 @@ expand_aggr_init_1 (tree binfo, tree true_exp, tree exp, tree init, int flags)
       /* If store_init_value returns NULL_TREE, the INIT has been
 	 record in the DECL_INITIAL for EXP.  That means there's
 	 nothing more we have to do.  */
-      if (store_init_value (exp, init))
-	finish_expr_stmt (build (INIT_EXPR, type, exp, init));
+      init = store_init_value (exp, init);
+      if (init)
+	finish_expr_stmt (init);
       return;
     }
 
diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index f839dddb..bad9b1e 100644
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -284,6 +284,108 @@ cxx_incomplete_type_error (tree value, tree type)
 }
 
 
+/* The recursive part of split_nonconstant_init.  DEST is an lvalue
+   expression to which INIT should be assigned.  INIT is a CONSTRUCTOR.
+   PCODE is a pointer to the tail of a chain of statements being emitted.
+   The return value is the new tail of that chain after new statements
+   are generated.  */
+
+static tree *
+split_nonconstant_init_1 (tree dest, tree init, tree *pcode)
+{
+  tree *pelt, elt, type = TREE_TYPE (dest);
+  tree sub, code, inner_type = NULL;
+  bool array_type_p = false;
+
+  pelt = &CONSTRUCTOR_ELTS (init);
+  switch (TREE_CODE (type))
+    {
+    case ARRAY_TYPE:
+      inner_type = TREE_TYPE (type);
+      array_type_p = true;
+      /* FALLTHRU */
+
+    case RECORD_TYPE:
+    case UNION_TYPE:
+    case QUAL_UNION_TYPE:
+      while ((elt = *pelt))
+	{
+	  tree field_index = TREE_PURPOSE (elt);
+	  tree value = TREE_VALUE (elt);
+
+	  if (!array_type_p)
+	    inner_type = TREE_TYPE (field_index);
+
+	  if (TREE_CODE (value) == CONSTRUCTOR)
+	    {
+	      if (array_type_p)
+	        sub = build (ARRAY_REF, inner_type, dest, field_index);
+	      else
+	        sub = build (COMPONENT_REF, inner_type, dest, field_index);
+
+	      pcode = split_nonconstant_init_1 (sub, value, pcode);
+	    }
+	  else if (!initializer_constant_valid_p (value, inner_type))
+	    {
+	      *pelt = TREE_CHAIN (elt);
+
+	      if (array_type_p)
+	        sub = build (ARRAY_REF, inner_type, dest, field_index);
+	      else
+	        sub = build (COMPONENT_REF, inner_type, dest, field_index);
+
+	      code = build (MODIFY_EXPR, inner_type, sub, value);
+	      code = build_stmt (EXPR_STMT, code);
+
+	      *pcode = code;
+	      pcode = &TREE_CHAIN (code);
+	      continue;
+	    }
+	  pelt = &TREE_CHAIN (elt);
+	}
+      break;
+
+    case VECTOR_TYPE:
+      if (!initializer_constant_valid_p (init, type))
+	{
+	  CONSTRUCTOR_ELTS (init) = NULL;
+	  code = build (MODIFY_EXPR, type, dest, init);
+	  code = build_stmt (EXPR_STMT, code);
+	  pcode = &TREE_CHAIN (code);
+	}
+      break;
+
+    default:
+      abort ();
+    }
+
+  return pcode;
+}
+
+/* A subroutine of store_init_value.  Splits non-constant static 
+   initializer INIT into a constant part and generates code to
+   perform the non-constant part of the initialization to DEST.
+   Returns the code for the runtime init.  */
+
+static tree
+split_nonconstant_init (tree dest, tree init)
+{
+  tree code;
+
+  if (TREE_CODE (init) == CONSTRUCTOR)
+    {
+      code = build_stmt (COMPOUND_STMT, NULL_TREE);
+      split_nonconstant_init_1 (dest, init, &COMPOUND_BODY (code));
+      code = build1 (STMT_EXPR, void_type_node, code);
+      TREE_SIDE_EFFECTS (code) = 1;
+      DECL_INITIAL (dest) = init;
+    }
+  else
+    code = build (INIT_EXPR, TREE_TYPE (dest), dest, init);
+
+  return code;
+}
+
 /* Perform appropriate conversions on the initial value of a variable,
    store it in the declaration DECL,
    and print any error messages that are appropriate.
@@ -299,9 +401,8 @@ cxx_incomplete_type_error (tree value, tree type)
    into a CONSTRUCTOR and use standard initialization techniques.
    Perhaps a warning should be generated?
 
-   Returns value of initializer if initialization could not be
-   performed for static variable.  In that case, caller must do
-   the storing.  */
+   Returns code to be executed if initialization could not be performed
+   for static variable.  In that case, caller must emit the code.  */
 
 tree
 store_init_value (tree decl, tree init)
@@ -356,11 +457,11 @@ store_init_value (tree decl, tree init)
      constructing never make it into DECL_INITIAL, and passes 'init' to
      build_aggr_init without checking DECL_INITIAL.  So just return.  */
   else if (TYPE_NEEDS_CONSTRUCTING (type))
-    return value;
+    return build (INIT_EXPR, type, decl, value);
   else if (TREE_STATIC (decl)
 	   && (! TREE_CONSTANT (value)
 	       || ! initializer_constant_valid_p (value, TREE_TYPE (value))))
-    return value;
+    return split_nonconstant_init (decl, value);
   
   /* Store the VALUE in DECL_INITIAL.  If we're building a
      statement-tree we will actually expand the initialization later