contrib/gcc/reg-stack.c

31    them is not known until this pass is run.  On output, hard register
34    numbers completely overlap - before this pass, all stack register
43    after this pass is done.
47    After this pass, hard register numbers represent the distance from
103       use the input reg for an output reload.  Consider this example:
111       the output, if input B dies in this insn.
121       output operands fall in this category - there is no other way to
123       this in the constraints.
181 /* We use this array to cache info about insns, because otherwise we
349   /* Search forward looking for the first use of this value.
366 /* Reorganize the stack into ascending numbers, before this insn.  */
460    follow.  Those rules are explained at the top of this file: the rule
479      alternative matches, this asm is malformed.  */
492       /* Avoid further trouble with this insn.  */
618      ??? Detect this more deterministically by having constrain_asm_operands
637       /* Avoid further trouble with this insn.  */
722   rtx *note_link, this;
725   for (this = *note_link; this; this = XEXP (this, 1))
726     if (REG_NOTE_KIND (this) == note
727 	&& REG_P (XEXP (this, 0)) && REGNO (XEXP (this, 0)) == regno)
729 	*note_link = XEXP (this, 1);
733       note_link = &XEXP (this, 1);
758    REGSTACK is the stack state after INSN and is updated to reflect this
895   /* Avoid emitting the swap if this is the first register stack insn
897      and let compensate edges take care of this for us.  */
989 	  /* If this is a no-op move, there must not be a REG_DEAD note.  */
999 	  /* If the source is not live, this is yet another case of
1004 	  /* It is possible that the dest is unused after this insn.
1023       /* If this appears to be a no-op move, delete it, or else it
1067 	     this by reading back the value from the MEM.
1174   /* See if this is, or ends in, a fnstsw.  If so, we're not doing anything
1184       /* Search forward looking for the first use of this value.
1199       /* So we've found the insn using this value.  If it is anything
1209       /* Now we are prepared to handle this as a normal cc0 setter.  */
1245    to do this - a `fcomp' followed by a `fstpl %st(0)' may be easier to
1258      registers that die in this insn - move those to stack top first.  */
1305       /* As a special case, two regs may die in this insn if src2 is
1372 		   its own scratch register.  It does this by clobbering
1392 		   all other clobbers, this must be due to a function
1428 	/* See if this is a `movM' pattern, and handle elsewhere if so.  */
1835 		   CSE.  When optimizing this would have been broken
1951    asm_operands left in the RTL at this point may be assume to meet the
2078 	   actual reg this operand needs to be in.  */
2175      ???  Explain why this is true.  */
2179       /* See if there is an output for this hard reg.  */
2251 	 registers for this call, make sure they are in the right
2311   /* If this a noreturn call, we can't insert pop insns after it.
2321   /* If there is a REG_UNUSED note on a stack register on this insn,
2350    is no longer needed once this has executed.  */
2405 		  /* If this is a preference for the new top of stack, record
2452 	 pop the top of the stack, as this permits the use of the faster
2503 	 its correct slot, this algorithm will converge.  */
2536       /* At this point there must be no differences.  */
2745      insn scheduling.  We can do this when there is only one
2849 	 use as a template for this basic block.  */
2872   /* Process all insns in this block.  Keep track of NEXT so that we
2946      Note that, at this point, the CFG may have been damaged by the emission
2954      better to detect this earlier and avoid creating the EH edge in the first
3002 	 is that there is no way to preventively detect this case so we