===================================================================
@@ -1569,7 +1569,11 @@ extract_bit_field_1 (rtx str_rtx, unsign
enum extraction_pattern pattern = unsignedp ? EP_extzv : EP_extv;
extraction_insn extv;
if (!MEM_P (op0)
- && get_best_reg_extraction_insn (&extv, pattern, bitnum + bitsize,
+ /* ??? We could limit the structure size to the part of OP0 that
+ contains the field, with appropriate checks for endianness
+ and TRULY_NOOP_TRUNCATION. */
+ && get_best_reg_extraction_insn (&extv, pattern,
+ GET_MODE_BITSIZE (GET_MODE (op0)),
tmode))
{
rtx result = extract_bit_field_using_extv (&extv, op0, bitsize, bitnum,