xtensa: Revise complex hard register clobber elimination

In the previously posted patch
"xtensa: Make complex hard register clobber elimination more robust and accurate",
the check code for insns that refer to the [DS]Cmode hard register before
it is overwritten after it is clobbered is incomplete.  Fortunately such
insns are seldom emitted, so it didn't matter.

This patch fixes that for the sake of completeness.

gcc/ChangeLog:

	* config/xtensa/xtensa.md:
	Fix exit from loops detecting references before overwriting in the
	split pattern.

1 files changed, 37 insertions, 35 deletions

diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index dd3fc37..d3996b2 100644
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -2973,45 +2973,47 @@
 {
   auto_sbitmap bmp (FIRST_PSEUDO_REGISTER);
   rtx_insn *insn;
-  rtx reg = gen_rtx_REG (SImode, 0);
+  rtx reg = gen_rtx_REG (SImode, 0), dest;
+  unsigned int regno;
+  sbitmap_iterator iter;
   bitmap_set_range (bmp, REGNO (operands[0]), REG_NREGS (operands[0]));
   for (insn = next_nonnote_nondebug_insn_bb (curr_insn);
        insn; insn = next_nonnote_nondebug_insn_bb (insn))
-    {
-      sbitmap_iterator iter;
-      unsigned int regno;
-      if (NONJUMP_INSN_P (insn))
-	{
-	  EXECUTE_IF_SET_IN_BITMAP (bmp, 2, regno, iter)
-	    {
-	      set_regno_raw (reg, regno, REG_NREGS (reg));
-	      if (reg_overlap_mentioned_p (reg, PATTERN (insn)))
-		break;
-	    }
-	  if (GET_CODE (PATTERN (insn)) == SET)
-	    {
-	      rtx x = SET_DEST (PATTERN (insn));
-	      if (REG_P (x) && HARD_REGISTER_P (x))
-		bitmap_clear_range (bmp, REGNO (x), REG_NREGS (x));
-	      else if (SUBREG_P (x) && HARD_REGISTER_P (SUBREG_REG (x)))
-		{
-		  struct subreg_info info;
-		  subreg_get_info (regno = REGNO (SUBREG_REG (x)),
-				   GET_MODE (SUBREG_REG (x)),
-				   SUBREG_BYTE (x), GET_MODE (x), &info);
-		  if (!info.representable_p)
-		    break;
-		  bitmap_clear_range (bmp, regno + info.offset, info.nregs);
-		}
-	    }
-	  if (bitmap_empty_p (bmp))
-	    goto FALLTHRU;
-	}
-      else if (CALL_P (insn))
+    if (NONJUMP_INSN_P (insn))
+      {
 	EXECUTE_IF_SET_IN_BITMAP (bmp, 2, regno, iter)
-	 if (call_used_or_fixed_reg_p (regno))
-	   break;
-    }
+	  {
+	    set_regno_raw (reg, regno, REG_NREGS (reg));
+	    if (reg_referenced_p (reg, PATTERN (insn)))
+	      goto ABORT;
+	  }
+	if (GET_CODE (PATTERN (insn)) == SET
+	    || GET_CODE (PATTERN (insn)) == CLOBBER)
+	  {
+	    dest = SET_DEST (PATTERN (insn));
+	    if (REG_P (dest) && HARD_REGISTER_P (dest))
+	      bitmap_clear_range (bmp, REGNO (dest), REG_NREGS (dest));
+	    else if (SUBREG_P (dest)
+		     && HARD_REGISTER_P (SUBREG_REG (dest)))
+	      {
+		struct subreg_info info;
+		subreg_get_info (regno = REGNO (SUBREG_REG (dest)),
+				 GET_MODE (SUBREG_REG (dest)),
+				 SUBREG_BYTE (dest), GET_MODE (dest),
+				 &info);
+		if (!info.representable_p)
+		  break;
+		bitmap_clear_range (bmp, regno + info.offset, info.nregs);
+	      }
+	  }
+	if (bitmap_empty_p (bmp))
+	  goto FALLTHRU;
+      }
+    else if (CALL_P (insn))
+      EXECUTE_IF_SET_IN_BITMAP (bmp, 2, regno, iter)
+	if (call_used_or_fixed_reg_p (regno))
+	  goto ABORT;
+ABORT:
   FAIL;
 FALLTHRU:;
 })