Remove CC0

This removes CC0 and all directly related infrastructure.

CC_STATUS, CC_STATUS_MDEP, CC_STATUS_MDEP_INIT, and NOTICE_UPDATE_CC
are deleted and poisoned.  CC0 is only deleted (some targets use that
name for something else).  HAVE_cc0 is automatically generated, and we
no longer will do that after this patch.

CC_STATUS_INIT is suggested in final.c to also be useful for ports that
are not CC0, and at least arm seems to use it for something.  So I am
leaving that alone, but most targets that have it could remove it.

2021-05-04  Segher Boessenkool  <segher@kernel.crashing.org>

	* caller-save.c: Remove CC0.
	* cfgcleanup.c: Remove CC0.
	* cfgrtl.c: Remove CC0.
	* combine.c: Remove CC0.
	* compare-elim.c: Remove CC0.
	* conditions.h: Remove CC0.
	* config/h8300/h8300.h: Remove CC0.
	* config/h8300/h8300-protos.h: Remove CC0.
	* config/h8300/peepholes.md: Remove CC0.
	* config/i386/x86-tune-sched.c: Remove CC0.
	* config/m68k/m68k.c: Remove CC0.
	* config/rl78/rl78.c: Remove CC0.
	* config/sparc/sparc.c: Remove CC0.
	* config/xtensa/xtensa.c: Remove CC0.
	(gen_conditional_move):  Use pc_rtx instead of cc0_rtx in a piece of
	RTL where that is used as a placeholder only.
	* cprop.c: Remove CC0.
	* cse.c: Remove CC0.
	* cselib.c: Remove CC0.
	* df-problems.c: Remove CC0.
	* df-scan.c: Remove CC0.
	* doc/md.texi: Remove CC0.  Adjust an example.
	* doc/rtl.texi: Remove CC0.  Adjust an example.
	* doc/tm.texi: Regenerate.
	* doc/tm.texi.in: Remove CC0.
	* emit-rtl.c: Remove CC0.
	* final.c: Remove CC0.
	* fwprop.c: Remove CC0.
	* gcse-common.c: Remove CC0.
	* gcse.c: Remove CC0.
	* genattrtab.c: Remove CC0.
	* genconfig.c: Remove CC0.
	* genemit.c: Remove CC0.
	* genextract.c: Remove CC0.
	* gengenrtl.c: Remove CC0.
	* genrecog.c: Remove CC0.
	* haifa-sched.c: Remove CC0.
	* ifcvt.c: Remove CC0.
	* ira-costs.c: Remove CC0.
	* ira.c: Remove CC0.
	* jump.c: Remove CC0.
	* loop-invariant.c: Remove CC0.
	* lra-constraints.c: Remove CC0.
	* lra-eliminations.c: Remove CC0.
	* optabs.c: Remove CC0.
	* postreload-gcse.c: Remove CC0.
	* postreload.c: Remove CC0.
	* print-rtl.c: Remove CC0.
	* read-rtl-function.c: Remove CC0.
	* reg-notes.def: Remove CC0.
	* reg-stack.c: Remove CC0.
	* reginfo.c: Remove CC0.
	* regrename.c: Remove CC0.
	* reload.c: Remove CC0.
	* reload1.c: Remove CC0.
	* reorg.c: Remove CC0.
	* resource.c: Remove CC0.
	* rtl.c: Remove CC0.
	* rtl.def: Remove CC0.
	* rtl.h: Remove CC0.
	* rtlanal.c: Remove CC0.
	* sched-deps.c: Remove CC0.
	* sched-rgn.c: Remove CC0.
	* shrink-wrap.c: Remove CC0.
	* simplify-rtx.c: Remove CC0.
	* system.h: Remove CC0.  Poison NOTICE_UPDATE_CC, CC_STATUS_MDEP_INIT,
	CC_STATUS_MDEP, and CC_STATUS.
	* target.def: Remove CC0.
	* valtrack.c: Remove CC0.
	* var-tracking.c: Remove CC0.

1 files changed, 3 insertions, 22 deletions

diff --git a/gcc/gcse.c b/gcc/gcse.c
index 210dc7b..9114f30 100644
--- a/gcc/gcse.c
+++ b/gcc/gcse.c
@@ -926,7 +926,6 @@ oprs_unchanged_p (const_rtx x, const rtx_insn *insn, int avail_p)
       return 0;
 
     case PC:
-    case CC0: /*FIXME*/
     case CONST:
     CASE_CONST_ANY:
     case SYMBOL_REF:
@@ -2031,33 +2030,15 @@ insert_insn_end_basic_block (struct gcse_expr *expr, basic_block bb)
   while (NEXT_INSN (pat_end) != NULL_RTX)
     pat_end = NEXT_INSN (pat_end);
 
-  /* If the last insn is a jump, insert EXPR in front [taking care to
-     handle cc0, etc. properly].  Similarly we need to care trapping
-     instructions in presence of non-call exceptions.  */
+  /* If the last insn is a jump, insert EXPR in front.  Similarly we need to
+     take care of trapping instructions in presence of non-call exceptions.  */
 
   if (JUMP_P (insn)
       || (NONJUMP_INSN_P (insn)
 	  && (!single_succ_p (bb)
 	      || single_succ_edge (bb)->flags & EDGE_ABNORMAL)))
     {
-      /* FIXME: 'twould be nice to call prev_cc0_setter here but it aborts
-	 if cc0 isn't set.  */
-      if (HAVE_cc0)
-	{
-	  rtx note = find_reg_note (insn, REG_CC_SETTER, NULL_RTX);
-	  if (note)
-	    insn = safe_as_a <rtx_insn *> (XEXP (note, 0));
-	  else
-	    {
-	      rtx_insn *maybe_cc0_setter = prev_nonnote_insn (insn);
-	      if (maybe_cc0_setter
-		  && INSN_P (maybe_cc0_setter)
-		  && sets_cc0_p (PATTERN (maybe_cc0_setter)))
-		insn = maybe_cc0_setter;
-	    }
-	}
-
-      /* FIXME: What if something in cc0/jump uses value set in new insn?  */
+      /* FIXME: What if something in jump uses value set in new insn?  */
       new_insn = emit_insn_before_noloc (pat, insn, bb);
     }