tree-sra.c (scalarize_use): Adjust the vpos argument to sra_explode_bitfield_assignme...

gcc/
	* tree-sra.c (scalarize_use): Adjust the vpos argument to
	sra_explode_bitfield_assignment in cases where the type is
	wider than the bitfield.

From-SVN: r130408

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index c74de4f..6308dae 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2007-11-25  Richard Sandiford  <rsandifo@nildram.co.uk>
+
+       * tree-sra.c (scalarize_use): Adjust the vpos argument to
+       sra_explode_bitfield_assignment in cases where the type is
+       wider than the bitfield.
+
 2007-11-25  Richard Guenther  <rguenther@suse.de>
 
        * tree.h (struct tree_block): Move locus member next to

diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index 7060d54..83c5d8a 100644 (file)
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -3147,7 +3147,7 @@ scalarize_use (struct sra_elt *elt, tree *expr_p, block_stmt_iterator *bsi,
       if (!elt->use_block_copy)
        {
          tree type = TREE_TYPE (bfexpr);
-         tree var = make_rename_temp (type, "SR"), tmp, st;
+         tree var = make_rename_temp (type, "SR"), tmp, st, vpos;
 
          GIMPLE_STMT_OPERAND (stmt, 0) = var;
          update = true;
@@ -3162,8 +3162,16 @@ scalarize_use (struct sra_elt *elt, tree *expr_p, block_stmt_iterator *bsi,
              var = tmp;
            }
 
+         /* If VAR is wider than BLEN bits, it is padded at the
+            most-significant end.  We want to set VPOS such that
+            <BIT_FIELD_REF VAR BLEN VPOS> would refer to the
+            least-significant BLEN bits of VAR.  */
+         if (BYTES_BIG_ENDIAN)
+           vpos = size_binop (MINUS_EXPR, TYPE_SIZE (type), blen);
+         else
+           vpos = bitsize_int (0);
          sra_explode_bitfield_assignment
-           (var, bitsize_int (0), false, &listafter, blen, bpos, elt);
+           (var, vpos, false, &listafter, blen, bpos, elt);
        }
       else
        sra_sync_for_bitfield_assignment
@@ -3199,7 +3207,7 @@ scalarize_use (struct sra_elt *elt, tree *expr_p, block_stmt_iterator *bsi,
       if (!elt->use_block_copy)
        {
          tree type = TREE_TYPE (bfexpr);
-         tree var;
+         tree var, vpos;
 
          if (!TYPE_UNSIGNED (type))
            type = unsigned_type_for (type);
@@ -3210,8 +3218,16 @@ scalarize_use (struct sra_elt *elt, tree *expr_p, block_stmt_iterator *bsi,
                                    (var, build_int_cst_wide (type, 0, 0)),
                                    &list);
 
+         /* If VAR is wider than BLEN bits, it is padded at the
+            most-significant end.  We want to set VPOS such that
+            <BIT_FIELD_REF VAR BLEN VPOS> would refer to the
+            least-significant BLEN bits of VAR.  */
+         if (BYTES_BIG_ENDIAN)
+           vpos = size_binop (MINUS_EXPR, TYPE_SIZE (type), blen);
+         else
+           vpos = bitsize_int (0);
          sra_explode_bitfield_assignment
-           (var, bitsize_int (0), true, &list, blen, bpos, elt);
+           (var, vpos, true, &list, blen, bpos, elt);
 
          GIMPLE_STMT_OPERAND (stmt, 1) = var;
          update = true;