/* Optimize jump instructions, for GNU compiler.
- Copyright (C) 1987, 88, 89, 91-95, 1996 Free Software Foundation, Inc.b
+ Copyright (C) 1987, 88, 89, 91-95, 1996 Free Software Foundation, Inc.
This file is part of GNU CC.
We could handle BLKmode if (1) emit_store_flag could
and (2) we could find the size reliably. */
&& GET_MODE (XEXP (temp4, 0)) != BLKmode
- /* No point in doing any of this if branches are cheap or we
- don't have conditional moves. */
- && (BRANCH_COST >= 2
-#ifdef HAVE_conditional_move
- || 1
-#endif
- )
+ /* Even if branches are cheap, the store_flag optimization
+ can win when the operation to be performed can be
+ expressed directly. */
#ifdef HAVE_cc0
/* If the previous insn sets CC0 and something else, we can't
do this since we are going to delete that insn. */
can reverse the condition. See if (3) applies possibly
by reversing the condition. Prefer reversing to (4) when
branches are very expensive. */
- && ((reversep = 0, temp2 == const0_rtx)
- || (temp3 == const0_rtx
+ && (((BRANCH_COST >= 2
+ || STORE_FLAG_VALUE == -1
+ || (STORE_FLAG_VALUE == 1
+ /* Check that the mask is a power of two,
+ so that it can probably be generated
+ with a shift. */
+ && exact_log2 (INTVAL (temp3)) >= 0))
+ && (reversep = 0, temp2 == const0_rtx))
+ || ((BRANCH_COST >= 2
+ || STORE_FLAG_VALUE == -1
+ || (STORE_FLAG_VALUE == 1
+ && exact_log2 (INTVAL (temp2)) >= 0))
+ && temp3 == const0_rtx
&& (reversep = can_reverse_comparison_p (temp4, insn)))
|| (BRANCH_COST >= 2
&& GET_CODE (temp2) == CONST_INT