+ /* Extending a widening multiplication should be canonicalized to
+ a wider widening multiplication. */
+ if (GET_CODE (op) == MULT)
+ {
+ rtx lhs = XEXP (op, 0);
+ rtx rhs = XEXP (op, 1);
+ enum rtx_code lcode = GET_CODE (lhs);
+ enum rtx_code rcode = GET_CODE (rhs);
+
+ /* Widening multiplies usually extend both operands, but sometimes
+ they use a shift to extract a portion of a register. */
+ if ((lcode == ZERO_EXTEND
+ || (lcode == LSHIFTRT && CONST_INT_P (XEXP (lhs, 1))))
+ && (rcode == ZERO_EXTEND
+ || (rcode == LSHIFTRT && CONST_INT_P (XEXP (rhs, 1)))))
+ {
+ enum machine_mode lmode = GET_MODE (lhs);
+ enum machine_mode rmode = GET_MODE (rhs);
+ int bits;
+
+ if (lcode == LSHIFTRT)
+ /* Number of bits not shifted off the end. */
+ bits = GET_MODE_PRECISION (lmode) - INTVAL (XEXP (lhs, 1));
+ else /* lcode == ZERO_EXTEND */
+ /* Size of inner mode. */
+ bits = GET_MODE_PRECISION (GET_MODE (XEXP (lhs, 0)));
+
+ if (rcode == LSHIFTRT)
+ bits += GET_MODE_PRECISION (rmode) - INTVAL (XEXP (rhs, 1));
+ else /* rcode == ZERO_EXTEND */
+ bits += GET_MODE_PRECISION (GET_MODE (XEXP (rhs, 0)));
+
+ /* We can only widen multiplies if the result is mathematiclly
+ equivalent. I.e. if overflow was impossible. */
+ if (bits <= GET_MODE_PRECISION (GET_MODE (op)))
+ return simplify_gen_binary
+ (MULT, mode,
+ simplify_gen_unary (ZERO_EXTEND, mode, lhs, lmode),
+ simplify_gen_unary (ZERO_EXTEND, mode, rhs, rmode));
+ }
+ }
+
+ /* (zero_extend:M (zero_extend:N <X>)) is (zero_extend:M <X>). */
+ if (GET_CODE (op) == ZERO_EXTEND)
+ return simplify_gen_unary (ZERO_EXTEND, mode, XEXP (op, 0),
+ GET_MODE (XEXP (op, 0)));
+
+ /* (zero_extend:M (lshiftrt:N (ashift <X> (const_int I)) (const_int I)))
+ is (zero_extend:M (subreg:O <X>)) if there is mode with
+ GET_MODE_BITSIZE (N) - I bits. */
+ if (GET_CODE (op) == LSHIFTRT
+ && GET_CODE (XEXP (op, 0)) == ASHIFT
+ && CONST_INT_P (XEXP (op, 1))
+ && XEXP (XEXP (op, 0), 1) == XEXP (op, 1)
+ && GET_MODE_BITSIZE (GET_MODE (op)) > INTVAL (XEXP (op, 1)))
+ {
+ enum machine_mode tmode
+ = mode_for_size (GET_MODE_BITSIZE (GET_MODE (op))
+ - INTVAL (XEXP (op, 1)), MODE_INT, 1);
+ if (tmode != BLKmode)
+ {
+ rtx inner =
+ rtl_hooks.gen_lowpart_no_emit (tmode, XEXP (XEXP (op, 0), 0));
+ return simplify_gen_unary (ZERO_EXTEND, mode, inner, tmode);
+ }
+ }
+