From: Nick Clifton <nickc@redhat.com>
Date: Fri, 19 Sep 2014 07:45:22 +0000 (+0000)
Subject: rl78.c (rl78_expand_epilogue): Generate a USE of the pop'ed registers so that DCE... 
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=553130b0bad4cca01e95a3e920bfb494b1b530c0;p=gcc.git

rl78.c (rl78_expand_epilogue): Generate a USE of the pop'ed registers so that DCE does not eliminate them.

	* config/rl78/rl78.c (rl78_expand_epilogue): Generate a USE of the
	pop'ed registers so that DCE does not eliminate them.

From-SVN: r215375
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 0330a13997c..82dd6139764 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,8 @@
+2014-09-19  Nick Clifton  <nickc@redhat.com>
+
+	* config/rl78/rl78.c (rl78_expand_epilogue): Generate a USE of the
+	pop'ed registers so that DCE does not eliminate them.
+
 2014-09-18  Jan Hubicka  <hubicka@ucw.cz>
 
 	PR lto/63298
diff --git a/gcc/config/rl78/rl78.c b/gcc/config/rl78/rl78.c
index 5fe1f6fc6c9..5c2a9c6ddc5 100644
--- a/gcc/config/rl78/rl78.c
+++ b/gcc/config/rl78/rl78.c
@@ -1136,10 +1136,19 @@ rl78_expand_epilogue (void)
   for (i = 15; i >= 0; i--)
     if (cfun->machine->need_to_push [i])
       {
+	rtx dest = gen_rtx_REG (HImode, i * 2);
+
 	if (TARGET_G10)
 	  {
-	    emit_insn (gen_pop (gen_rtx_REG (HImode, 0)));
-	    emit_move_insn (gen_rtx_REG (HImode, i*2), gen_rtx_REG (HImode, 0));
+	    rtx ax = gen_rtx_REG (HImode, 0);
+
+	    emit_insn (gen_pop (ax));
+	    if (i != 0)
+	      {
+		emit_move_insn (dest, ax);
+		/* Generate a USE of the pop'd register so that DCE will not eliminate the move.  */
+		emit_insn (gen_use (dest));
+	      }
 	  }
 	else
 	  {
@@ -1150,7 +1159,7 @@ rl78_expand_epilogue (void)
 		emit_insn (gen_sel_rb (GEN_INT (need_bank)));
 		rb = need_bank;
 	      }
-	    emit_insn (gen_pop (gen_rtx_REG (HImode, i * 2)));
+	    emit_insn (gen_pop (dest));
 	  }
       }