PR target/15941

	* function.c (assign_parms): If not padding upward or intentionally
	forcing upward padding, take offset_rtx into account when determining
	the alignment for stack_parm.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@83396 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 19 insertions, 2 deletions

diff --git a/gcc/function.c b/gcc/function.c
index f4f2940f2eb..3f1f45bbcaa 100644
--- a/gcc/function.c
+++ b/gcc/function.c
@@ -4603,6 +4603,7 @@ assign_parms (tree fndecl)
 
       {
 	rtx offset_rtx;
+	unsigned int align, boundary;
 
 	/* If we're passing this arg using a reg, make its stack home
 	   the aligned stack slot.  */
@@ -4620,8 +4621,24 @@ assign_parms (tree fndecl)
 						  offset_rtx));
 
 	set_mem_attributes (stack_parm, parm, 1);
-	set_mem_align (stack_parm, 
-		       FUNCTION_ARG_BOUNDARY (promoted_mode, passed_type));
+
+	boundary = FUNCTION_ARG_BOUNDARY (promoted_mode, passed_type);
+	align = 0;
+
+	/* If we're padding upward, we know that the alignment of the slot
+	   is FUNCTION_ARG_BOUNDARY.  If we're using slot_offset, we're
+	   intentionally forcing upward padding.  Otherwise we have to come
+	   up with a guess at the alignment based on OFFSET_RTX.  */
+	if (locate.where_pad == upward || entry_parm)
+	  align = boundary;
+	else if (GET_CODE (offset_rtx) == CONST_INT)
+	  {
+	    align = INTVAL (offset_rtx) * BITS_PER_UNIT | boundary;
+	    align = align & -align;
+	  }
+	if (align > 0)
+	  set_mem_align (stack_parm, align);
+
 	if (entry_parm)
 	  set_reg_attrs_for_parm (entry_parm, stack_parm);
       }