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, 45 deletions

diff --git a/gcc/reload.c b/gcc/reload.c
index e18e27c..d21be91 100644
--- a/gcc/reload.c
+++ b/gcc/reload.c
@@ -1500,27 +1500,6 @@ push_reload (rtx in, rtx out, rtx *inloc, rtx *outloc,
   if (in != 0 && in != *inloc)
     rld[i].nocombine = 1;
 
-#if 0
-  /* This was replaced by changes in find_reloads_address_1 and the new
-     function inc_for_reload, which go with a new meaning of reload_inc.  */
-
-  /* If this is an IN/OUT reload in an insn that sets the CC,
-     it must be for an autoincrement.  It doesn't work to store
-     the incremented value after the insn because that would clobber the CC.
-     So we must do the increment of the value reloaded from,
-     increment it, store it back, then decrement again.  */
-  if (out != 0 && sets_cc0_p (PATTERN (this_insn)))
-    {
-      out = 0;
-      rld[i].out = 0;
-      rld[i].inc = find_inc_amount (PATTERN (this_insn), in);
-      /* If we did not find a nonzero amount-to-increment-by,
-	 that contradicts the belief that IN is being incremented
-	 in an address in this insn.  */
-      gcc_assert (rld[i].inc != 0);
-    }
-#endif
-
   /* If we will replace IN and OUT with the reload-reg,
      record where they are located so that substitution need
      not do a tree walk.  */
@@ -2696,17 +2675,10 @@ find_reloads (rtx_insn *insn, int replace, int ind_levels, int live_known,
 	}
     }
 
-  /* JUMP_INSNs and CALL_INSNs are not allowed to have any output reloads;
-     neither are insns that SET cc0.  Insns that use CC0 are not allowed
-     to have any input reloads.  */
+  /* JUMP_INSNs and CALL_INSNs are not allowed to have any output reloads.  */
   if (JUMP_P (insn) || CALL_P (insn))
     no_output_reloads = 1;
 
-  if (HAVE_cc0 && reg_referenced_p (cc0_rtx, PATTERN (insn)))
-    no_input_reloads = 1;
-  if (HAVE_cc0 && reg_set_p (cc0_rtx, PATTERN (insn)))
-    no_output_reloads = 1;
-
   /* The eliminated forms of any secondary memory locations are per-insn, so
      clear them out here.  */
 
@@ -4585,15 +4557,6 @@ find_reloads (rtx_insn *insn, int replace, int ind_levels, int live_known,
 	    rld[j].in = 0;
 	  }
 
-  /* If we made any reloads for addresses, see if they violate a
-     "no input reloads" requirement for this insn.  But loads that we
-     do after the insn (such as for output addresses) are fine.  */
-  if (HAVE_cc0 && no_input_reloads)
-    for (i = 0; i < n_reloads; i++)
-      gcc_assert (rld[i].in == 0
-		  || rld[i].when_needed == RELOAD_FOR_OUTADDR_ADDRESS
-		  || rld[i].when_needed == RELOAD_FOR_OUTPUT_ADDRESS);
-
   /* Compute reload_mode and reload_nregs.  */
   for (i = 0; i < n_reloads; i++)
     {
@@ -5323,7 +5286,6 @@ subst_reg_equivs (rtx ad, rtx_insn *insn)
     case SYMBOL_REF:
     case LABEL_REF:
     case PC:
-    case CC0:
       return ad;
 
     case REG:
@@ -5862,7 +5824,7 @@ find_reloads_address_1 (machine_mode mode, addr_space_t as,
 	      /* If we can output the register afterwards, do so, this
 		 saves the extra update.
 		 We can do so if we have an INSN - i.e. no JUMP_INSN nor
-		 CALL_INSN - and it does not set CC0.
+		 CALL_INSN.
 		 But don't do this if we cannot directly address the
 		 memory location, since this will make it harder to
 		 reuse address reloads, and increases register pressure.
@@ -5872,9 +5834,6 @@ find_reloads_address_1 (machine_mode mode, addr_space_t as,
 			   : reg_equiv_mem (regno));
 	      enum insn_code icode = optab_handler (add_optab, GET_MODE (x));
 	      if (insn && NONJUMP_INSN_P (insn)
-#if HAVE_cc0
-		  && ! sets_cc0_p (PATTERN (insn))
-#endif
 		  && (regno < FIRST_PSEUDO_REGISTER
 		      || (equiv
 			  && memory_operand (equiv, GET_MODE (equiv))
@@ -6621,8 +6580,7 @@ reg_overlap_mentioned_for_reload_p (rtx x, rtx in)
     }
   else if (MEM_P (x))
     return refers_to_mem_for_reload_p (in);
-  else if (GET_CODE (x) == SCRATCH || GET_CODE (x) == PC
-	   || GET_CODE (x) == CC0)
+  else if (GET_CODE (x) == SCRATCH || GET_CODE (x) == PC)
     return reg_mentioned_p (x, in);
   else
     {