(expand_function_start): Don't set up context_display

        unless current_function_needs_context.

From-SVN: r11615

diff --git a/gcc/function.c b/gcc/function.c
index bdbfa541c2935aed5138a052029cc1573c7ead0e..f6ffe09ce7a329d750106f1bff6b9dce2c5a5d21 100644 (file)
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -5230,48 +5230,52 @@ expand_function_start (subr, parms_have_cleanups)
        use_variable (current_function_internal_arg_pointer);
     }
 
-  /* Fetch static chain values for containing functions.  */
-  tem = decl_function_context (current_function_decl);
-  /* If not doing stupid register allocation copy the static chain
-     pointer into a pseudo.  If we have small register classes, copy the
-     value from memory if static_chain_incoming_rtx is a REG.  If we do
-     stupid register allocation, we use the stack address generated above.  */
-  if (tem && ! obey_regdecls)
+  context_display = 0;
+  if (current_function_needs_context)
     {
+      /* Fetch static chain values for containing functions.  */
+      tem = decl_function_context (current_function_decl);
+      /* If not doing stupid register allocation copy the static chain
+        pointer into a pseudo.  If we have small register classes, copy
+        the value from memory if static_chain_incoming_rtx is a REG.  If
+        we do stupid register allocation, we use the stack address
+        generated above.  */
+      if (tem && ! obey_regdecls)
+       {
 #ifdef SMALL_REGISTER_CLASSES
-      /* If the static chain originally came in a register, put it back
-        there, then move it out in the next insn.  The reason for
-        this peculiar code is to satisfy function integration.  */
-      if (GET_CODE (static_chain_incoming_rtx) == REG)
-       emit_move_insn (static_chain_incoming_rtx, last_ptr);
+         /* If the static chain originally came in a register, put it back
+            there, then move it out in the next insn.  The reason for
+            this peculiar code is to satisfy function integration.  */
+         if (GET_CODE (static_chain_incoming_rtx) == REG)
+           emit_move_insn (static_chain_incoming_rtx, last_ptr);
 #endif
 
-      last_ptr = copy_to_reg (static_chain_incoming_rtx);
-    }
+         last_ptr = copy_to_reg (static_chain_incoming_rtx);
+       }
 
-  context_display = 0;
-  while (tem)
-    {
-      tree rtlexp = make_node (RTL_EXPR);
+      while (tem)
+       {
+         tree rtlexp = make_node (RTL_EXPR);
 
-      RTL_EXPR_RTL (rtlexp) = last_ptr;
-      context_display = tree_cons (tem, rtlexp, context_display);
-      tem = decl_function_context (tem);
-      if (tem == 0)
-       break;
-      /* Chain thru stack frames, assuming pointer to next lexical frame
-        is found at the place we always store it.  */
+         RTL_EXPR_RTL (rtlexp) = last_ptr;
+         context_display = tree_cons (tem, rtlexp, context_display);
+         tem = decl_function_context (tem);
+         if (tem == 0)
+           break;
+         /* Chain thru stack frames, assuming pointer to next lexical frame
+            is found at the place we always store it.  */
 #ifdef FRAME_GROWS_DOWNWARD
-      last_ptr = plus_constant (last_ptr, - GET_MODE_SIZE (Pmode));
+         last_ptr = plus_constant (last_ptr, - GET_MODE_SIZE (Pmode));
 #endif
-      last_ptr = copy_to_reg (gen_rtx (MEM, Pmode,
-                                      memory_address (Pmode, last_ptr)));
-
-      /* If we are not optimizing, ensure that we know that this
-        piece of context is live over the entire function.  */
-      if (! optimize)
-       save_expr_regs = gen_rtx (EXPR_LIST, VOIDmode, last_ptr,
-                                 save_expr_regs);
+         last_ptr = copy_to_reg (gen_rtx (MEM, Pmode,
+                                          memory_address (Pmode, last_ptr)));
+
+         /* If we are not optimizing, ensure that we know that this
+            piece of context is live over the entire function.  */
+         if (! optimize)
+           save_expr_regs = gen_rtx (EXPR_LIST, VOIDmode, last_ptr,
+                                     save_expr_regs);
+       }
     }
 
   /* After the display initializations is where the tail-recursion label