From 1c407dc088231ba5f2cc63d9278f4b797db48de1 Mon Sep 17 00:00:00 2001
From: Takayuki 'January June' Suwa <jjsuwa_sys3175@yahoo.co.jp>
Date: Fri, 20 Jan 2023 12:33:37 +0900
Subject: [PATCH] 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.
---
 gcc/config/xtensa/xtensa.md | 72 +++++++++++++++++++------------------
 1 file changed, 37 insertions(+), 35 deletions(-)

diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index dd3fc37353b9..d3996b26cb5c 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:;
 })
-- 
2.47.2