[i386 PATCH] Tree type correctness in ix86_va_start

Roger Sayle roger@eyesopen.com
Tue Apr 4 03:29:00 GMT 2006


The following patch fixes another minor tree type mismatch issue
identified by instrumenting the middle-end.  In this case, the x86
back-end is constructing temporary MODIFY_EXPR trees where the LHS'
type doesn't match the RHS' type.   The problem is that the INTEGER_CSTs
that form the RHS are constructed without types.  This is unlikely to
ever be a problem, but it's good GCC coding style to specify consistent
types, especially as in this case the fix is trivial.  The obvious
patch below simply specifies the appropriate type to build_int_cst.

This patch has been tested on i686-pc-linux-gnu with a full "make
bootstrap", all default languages including Ada, and regression
tested with a top-level "make -k check" with no new failures.

Ok for mainline?



2006-04-03  Roger Sayle  <roger@eyesopen.com>

	* config/i386/i386.c (ix86_va_start): Ensure all integer constant
	trees are constructed with a suitable tree type.



Index: i386.c
===================================================================
*** i386.c	(revision 112626)
--- i386.c	(working copy)
*************** ix86_va_start (tree valist, rtx nextarg)
*** 4122,4127 ****
--- 4122,4128 ----
    HOST_WIDE_INT words, n_gpr, n_fpr;
    tree f_gpr, f_fpr, f_ovf, f_sav;
    tree gpr, fpr, ovf, sav, t;
+   tree type;

    /* Only 64bit target needs something special.  */
    if (!TARGET_64BIT)
*************** ix86_va_start (tree valist, rtx nextarg)
*** 4152,4177 ****

    if (cfun->va_list_gpr_size)
      {
!       t = build2 (MODIFY_EXPR, TREE_TYPE (gpr), gpr,
! 		  build_int_cst (NULL_TREE, n_gpr * 8));
        TREE_SIDE_EFFECTS (t) = 1;
        expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
      }

    if (cfun->va_list_fpr_size)
      {
!       t = build2 (MODIFY_EXPR, TREE_TYPE (fpr), fpr,
! 		  build_int_cst (NULL_TREE, n_fpr * 16 + 8*REGPARM_MAX));
        TREE_SIDE_EFFECTS (t) = 1;
        expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
      }

    /* Find the overflow area.  */
!   t = make_tree (TREE_TYPE (ovf), virtual_incoming_args_rtx);
    if (words != 0)
!     t = build2 (PLUS_EXPR, TREE_TYPE (ovf), t,
! 	        build_int_cst (NULL_TREE, words * UNITS_PER_WORD));
!   t = build2 (MODIFY_EXPR, TREE_TYPE (ovf), ovf, t);
    TREE_SIDE_EFFECTS (t) = 1;
    expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);

--- 4153,4181 ----

    if (cfun->va_list_gpr_size)
      {
!       type = TREE_TYPE (gpr);
!       t = build2 (MODIFY_EXPR, type, gpr,
! 		  build_int_cst (type, n_gpr * 8));
        TREE_SIDE_EFFECTS (t) = 1;
        expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
      }

    if (cfun->va_list_fpr_size)
      {
!       type = TREE_TYPE (fpr);
!       t = build2 (MODIFY_EXPR, type, fpr,
! 		  build_int_cst (type, n_fpr * 16 + 8*REGPARM_MAX));
        TREE_SIDE_EFFECTS (t) = 1;
        expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
      }

    /* Find the overflow area.  */
!   type = TREE_TYPE (ovf);
!   t = make_tree (type, virtual_incoming_args_rtx);
    if (words != 0)
!     t = build2 (PLUS_EXPR, type, t,
! 	        build_int_cst (type, words * UNITS_PER_WORD));
!   t = build2 (MODIFY_EXPR, type, ovf, t);
    TREE_SIDE_EFFECTS (t) = 1;
    expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);

*************** ix86_va_start (tree valist, rtx nextarg)
*** 4179,4186 ****
      {
        /* Find the register save area.
  	 Prologue of the function save it right above stack frame.  */
!       t = make_tree (TREE_TYPE (sav), frame_pointer_rtx);
!       t = build2 (MODIFY_EXPR, TREE_TYPE (sav), sav, t);
        TREE_SIDE_EFFECTS (t) = 1;
        expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
      }
--- 4183,4191 ----
      {
        /* Find the register save area.
  	 Prologue of the function save it right above stack frame.  */
!       type = TREE_TYPE (sav);
!       t = make_tree (type, frame_pointer_rtx);
!       t = build2 (MODIFY_EXPR, type, sav, t);
        TREE_SIDE_EFFECTS (t) = 1;
        expand_expr (t, const0_rtx, VOIDmode, EXPAND_NORMAL);
      }


Roger
--



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