calls.c (compute_argument_addresses): Force stack slots into alias set 0.

	* calls.c (compute_argument_addresses): Force stack slots into
	alias set 0.
	* expr.c (emit_push_insn): Force pushes into alias set 0.

From-SVN: r34662

3 files changed, 36 insertions, 14 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index f0062aa..4a37027 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2000-06-23  Jakub Jelinek  <jakub@redhat.com>
+
+	* calls.c (compute_argument_addresses): Force stack slots into
+	alias set 0.
+	* expr.c (emit_push_insn): Force pushes into alias set 0.
+
 2000-06-23  Richard Henderson  <rth@cygnus.com>
 
 	* config/ia64/ia64.md (pred_rel_mutex): Only take one register.
diff --git a/gcc/calls.c b/gcc/calls.c
index 5892cba..3561f59 100644
--- a/gcc/calls.c
+++ b/gcc/calls.c
@@ -1595,6 +1595,13 @@ compute_argument_addresses (args, argblock, num_actuals)
 	  args[i].stack_slot = gen_rtx_MEM (args[i].mode, addr);
 	  set_mem_attributes (args[i].stack_slot,
 			      TREE_TYPE (args[i].tree_value), 1);
+
+	  /* Function incoming arguments may overlap with sibling call
+	     outgoing arguments and we cannot allow reordering of reads
+	     from function arguments with stores to outgoing arguments
+	     of sibling calls.  */
+	  MEM_ALIAS_SET (args[i].stack) = 0;
+	  MEM_ALIAS_SET (args[i].stack_slot) = 0;
 	}
     }
 }
diff --git a/gcc/expr.c b/gcc/expr.c
index c981580..07fa592 100644
--- a/gcc/expr.c
+++ b/gcc/expr.c
@@ -3052,6 +3052,8 @@ emit_push_insn (x, mode, type, size, align, partial, reg, extra,
       else
 #endif /* PUSH_ROUNDING */
 	{
+	  rtx target;
+
 	  /* Otherwise make space on the stack and copy the data
 	     to the address of that space.  */
 
@@ -3086,8 +3088,6 @@ emit_push_insn (x, mode, type, size, align, partial, reg, extra,
 						  skip));
 	  if (current_function_check_memory_usage && ! in_check_memory_usage)
 	    {
-	      rtx target;
-	      
 	      in_check_memory_usage = 1;
 	      target = copy_to_reg (temp);
 	      if (GET_CODE (x) == MEM && type && AGGREGATE_TYPE_P (type))
@@ -3104,27 +3104,29 @@ emit_push_insn (x, mode, type, size, align, partial, reg, extra,
 	      in_check_memory_usage = 0;
 	    }
 
+	    target = gen_rtx_MEM (BLKmode, temp);
+
+	    if (type != 0)
+	      {
+		set_mem_attributes (target, type, 1);
+		/* Function incoming arguments may overlap with sibling call
+		   outgoing arguments and we cannot allow reordering of reads
+		   from function arguments with stores to outgoing arguments
+		   of sibling calls.  */
+		MEM_ALIAS_SET (target) = 0;
+	      }
+
 	  /* TEMP is the address of the block.  Copy the data there.  */
 	  if (GET_CODE (size) == CONST_INT
 	      && MOVE_BY_PIECES_P ((unsigned) INTVAL (size), align))
 	    {
-	      rtx target = gen_rtx_MEM (BLKmode, temp);
-
-	      if (type != 0)
-		set_mem_attributes (target, type, 1);
-
-	      move_by_pieces (gen_rtx_MEM (BLKmode, temp), xinner,
-			      INTVAL (size), align);
+	      move_by_pieces (target, xinner, INTVAL (size), align);
 	      goto ret;
 	    }
 	  else
 	    {
 	      rtx opalign = GEN_INT (align / BITS_PER_UNIT);
 	      enum machine_mode mode;
-	      rtx target = gen_rtx_MEM (BLKmode, temp);
-
-	      if (type != 0)
-		set_mem_attributes (target, type, 1);
 
 	      for (mode = GET_CLASS_NARROWEST_MODE (MODE_INT);
 		   mode != VOIDmode;
@@ -3293,7 +3295,14 @@ emit_push_insn (x, mode, type, size, align, partial, reg, extra,
 
       dest = gen_rtx_MEM (mode, addr);
       if (type != 0)
-	set_mem_attributes (dest, type, 1);
+	{
+	  set_mem_attributes (dest, type, 1);
+	  /* Function incoming arguments may overlap with sibling call
+	     outgoing arguments and we cannot allow reordering of reads
+	     from function arguments with stores to outgoing arguments
+	     of sibling calls.  */
+	  MEM_ALIAS_SET (dest) = 0;
+	}
 
       emit_move_insn (dest, x);