diff options
Diffstat (limited to 'gcc/expr.c')
| -rw-r--r-- | gcc/expr.c | 16 |
1 files changed, 15 insertions, 1 deletions
@@ -5215,7 +5215,21 @@ store_field (rtx target, HOST_WIDE_INT bitsize, HOST_WIDE_INT bitpos, && TREE_CODE (TYPE_SIZE (TREE_TYPE (exp))) == INTEGER_CST && compare_tree_int (TYPE_SIZE (TREE_TYPE (exp)), bitsize) != 0)) { - rtx temp = expand_expr (exp, NULL_RTX, VOIDmode, 0); + rtx temp; + + /* If EXP is a NOP_EXPR of precision less than its mode, then that + implies a mask operation. If the precision is the same size as + the field we're storing into, that mask is redundant. This is + particularly common with bit field assignments generated by the + C front end. */ + if (TREE_CODE (exp) == NOP_EXPR + && INTEGRAL_TYPE_P (TREE_TYPE (exp)) + && (TYPE_PRECISION (TREE_TYPE (exp)) + < GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (exp)))) + && bitsize == TYPE_PRECISION (TREE_TYPE (exp))) + exp = TREE_OPERAND (exp, 0); + + temp = expand_expr (exp, NULL_RTX, VOIDmode, 0); /* If BITSIZE is narrower than the size of the type of EXP we will be narrowing TEMP. Normally, what's wanted are the |