PR rtl-optimization/38245

	* calls.c (expand_call): Add stack arguments to
	CALL_INSN_FUNCTION_USAGE even for pure calls (when
	ACCUMULATE_OUTGOING_ARGS) and even for args partially passed
	in regs and partially in memory or BLKmode arguments.
	(emit_library_call_value_1): Add stack arguments to
	CALL_INSN_FUNCTION_USAGE even for pure calls (when
	ACCUMULATE_OUTGOING_ARGS).
	* dce.c: Include tm_p.h.
	(find_call_stack_args): New function.
	(deletable_insn_p): Call it for CALL_P insns.  Add ARG_STORES
	argument.
	(mark_insn): Call find_call_stack_args for CALL_Ps.
	(prescan_insns_for_dce): Walk insns backwards in bb rather than
	forwards.  Allocate and free arg_stores bitmap if needed, pass it
	down to deletable_insn_p, don't mark stores set in arg_stores
	bitmap, clear the bitmap at the beginning of each bb.
	* Makefile.in (dce.o): Depend on $(TM_P_H).

	* gcc.dg/pr38245-3.c: New test.
	* gcc.dg/pr38245-3.h: New file.
	* gcc.dg/pr38245-4.c: New file.
	* gcc.dg/pr38364.c: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@143387 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 25 insertions, 22 deletions

diff --git a/gcc/calls.c b/gcc/calls.c
index f6bc970b71b..a75e3b36569 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -1,6 +1,6 @@
 /* Convert function calls to rtl insns, for GNU C compiler.
    Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
-   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
+   1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
    Free Software Foundation, Inc.
 
 This file is part of GCC.
@@ -2705,26 +2705,28 @@ expand_call (tree exp, rtx target, int ignore)
 	 but we do preallocate space here if they want that.  */
 
       for (i = 0; i < num_actuals; i++)
-	if (args[i].reg == 0 || args[i].pass_on_stack)
-	  {
-	    rtx before_arg = get_last_insn ();
-
-	    if (store_one_arg (&args[i], argblock, flags,
-			       adjusted_args_size.var != 0,
-			       reg_parm_stack_space)
-		|| (pass == 0
-		    && check_sibcall_argument_overlap (before_arg,
-						       &args[i], 1)))
-	      sibcall_failure = 1;
-
-	    if (flags & ECF_CONST
-		&& args[i].stack
-		&& args[i].value == args[i].stack)
-	      call_fusage = gen_rtx_EXPR_LIST (VOIDmode,
-					       gen_rtx_USE (VOIDmode,
-							    args[i].value),
-					       call_fusage);
-	  }
+	{
+	  if (args[i].reg == 0 || args[i].pass_on_stack)
+	    {
+	      rtx before_arg = get_last_insn ();
+
+	      if (store_one_arg (&args[i], argblock, flags,
+				 adjusted_args_size.var != 0,
+				 reg_parm_stack_space)
+		  || (pass == 0
+		      && check_sibcall_argument_overlap (before_arg,
+							 &args[i], 1)))
+		sibcall_failure = 1;
+	      }
+
+	  if (((flags & ECF_CONST)
+	       || ((flags & ECF_PURE) && ACCUMULATE_OUTGOING_ARGS))
+	      && args[i].stack)
+	    call_fusage = gen_rtx_EXPR_LIST (VOIDmode,
+					     gen_rtx_USE (VOIDmode,
+							  args[i].stack),
+					     call_fusage);
+	}
 
       /* If we have a parm that is passed in registers but not in memory
 	 and whose alignment does not permit a direct copy into registers,
@@ -3672,7 +3674,8 @@ emit_library_call_value_1 (int retval, rtx orgfun, rtx value,
 
 	  NO_DEFER_POP;
 
-	  if (flags & ECF_CONST)
+	  if ((flags & ECF_CONST)
+	      || ((flags & ECF_PURE) && ACCUMULATE_OUTGOING_ARGS))
 	    {
 	      rtx use;