contrib/gcc/combine.c

36    LOG_LINKS does not have links for use of the CC0.  They don't
74    also use the condition code; but in practice such insns would not
171      to (hard or pseudo) register n.  We use this information to see if an
176      We use an approach similar to that used by cse, but change it in the
191 				to use the value of this register in some
459 /* It is not safe to use ordinary gen_lowpart in combine.
746   /* Don't use reg_stat[].nonzero_bits when computing it.  This can cause
759      Also set any known values so that we can use it while searching
1100 	     sign-extend it for use in reg_stat[].nonzero_bits because some
1292 	 use REG_RETVAL notes for noconflict blocks, but other code here
1300 	 does not use any registers whose values alter in between.  However,
1301 	 If the insns are adjacent, a use can't cross a set even though we
1372 	     reject use-and-clobber patterns.  */
1693   rtx use = BB_END (this_basic_block);
1702   if (!NONJUMP_INSN_P (use) || GET_CODE (PATTERN (use)) != USE || insn == use)
1704   reg = XEXP (PATTERN (use), 0);
1717   for (p = PREV_INSN (use); info.mask && p != insn; p = PREV_INSN (p))
1756      the next use of that destination.  */
2265   /* Many machines that don't use CC0 have insns that can both perform an
2458 	  /* If there is no I1, use I2's body as is.  We used to also not do
2570 	 use I2DEST as a scratch register will help.  In the latter case,
2575       /* We can only use I2DEST as a scratch reg if it doesn't overlap any
2634       /* If recog_for_combine has discarded clobbers, try to use them
2662 	     register status, so don't use these insns.  If I2's destination
2663 	     is used between I2 and I3, we also can't use these insns.  */
2674 	     If so, we must show an extra use of it.  */
2698       /* If we can split it and use I2DEST, go ahead and see if that
2706 	     or the only use of a pseudo, we can change its mode.
2852 	     don't use one now.  */
3349 	   zero its use count so it won't make `reload' do any work.  */
3529 	 the machine-specific way to split large constants.  We use
3869 	 an AND, but XEXP (X, 0) is, use it as our split point.  */
4217 	     to be simpler, so don't use it.  */
4228 	     false arms to store-flag values.  Be careful to use copy_rtx
4469 	     haven't improved anything, so don't use it.  Otherwise,
4676 	     (xor X 1) or (minus 1 X); we use the former.  Finally, if X is
4681 	     comparison.  It may now be simpler to use, e.g., an AND.  If a
5214   /* If we are setting CC0 or if the source is a COMPARE, look for the use of
5271 	 need to use a different CC mode here.  */
5350 	 needed.  If we do not use cc0, we always have a COMPARE.  */
5471      are comparing an item known to be 0 or -1 against 0, use a logical
5636       /* We can't necessarily use a const_int for a multiword mode;
6182   /* Get the mode to use should INNER not be a MEM, the mode for the position,
6326      have to zero extend.  Otherwise, we can just use a SUBREG.  */
6366   /* Make the required operation.  See if we can use existing rtx.  */
6434    We try, as much as possible, to re-use rtl expressions to save memory.
7130 	 the mode of the shift, refine which bits we need.  Otherwise, use the
7342 	 use the full mask inside the NOT.  */
7925   /* The mode to use for the source is the mode of the assignment, or of
8308   /* If X is a register whose nonzero bits value is current, use it.
8309      Otherwise, if X is a register whose value we can find, use that
8310      value.  Otherwise, use the previously-computed global nonzero bits
8336 	 sign-extend it for use in reg_nonzero_bits because some
8640 	 minus 1.  For ASHIFT, use the size minus one as the count (this can
8760 	  /* Some machines use MULT instead of ASHIFT because MULT
8917 	      /* Give up if we can't compute an outer operation to use.  */
9354      we use to indicate that something didn't match.  If we find such a
9439 /* Like gen_lowpart_general but for use by combine.  In combine it
9483       /* For use in case we fall down into the address adjustments
9564    The result is a possibly different comparison code to use.  *POP0 and
10707      which we can use the wider mode.  */
10723 	     we can use the wider mode.  Similarly for sign-extended
10924 	 so just use the CLOBBER.  */
11163    truncated to MODE.  In this case we can use a subreg to refer to
11394      And, if it's set only once, and it's always set before use, then all
11408      we can't use it even if the register was only set once.  */
11531      we allow the machine description to decide whether use-and-clobber
11838 	 value, so use that as the destination.  */
12062 	     be present on any use of the register in I2 or I3.  */
12181 	     REG_EQUAL note, the original use of the dying register
12185 	     FROM_INSN for the previous use or set of this register,
12200 	     use of A and put the death note there.  */
12280 			     First set the pattern to something that won't use