From: Bernd Schmidt <bernds@redhat.com>
Date: Wed, 28 Mar 2001 09:02:18 +0000 (+0000)
Subject: Avoid deleting labels that got put into the constant pool
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=f004c6fd92e0c8d93c33785c165440d58a7baf24;p=thirdparty%2Fgcc.git

Avoid deleting labels that got put into the constant pool

From-SVN: r40923
---

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 921089dda7c4..98efc07a0175 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2001-03-28  Bernd Schmidt  <bernds@redhat.com>
+
+	* flow.c (propagate_block): When trying to delete a case vector, cope
+	if its label has LABEL_PRESERVE_P set.
+	* jump.c (jump_optimize_1): Move call to delete_barrier_successors to
+	a point where JUMP_LABELS and LABEL_NUSES are set up properly.
+	(delete_barrier_successors): If deleting a table jump, delete the case
+	vector as well.
+	* varasm.c (force_const_mem): If we have a label, set LABEL_PRESERVE_P
+	so it won't get deleted.
+
 Tue Mar 20 18:31:48 2001  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	1999-11-30  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
diff --git a/gcc/flow.c b/gcc/flow.c
index 432a990220ab..f3b32139541c 100644
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -2744,15 +2744,23 @@ propagate_block (old, first, last, final, significant, bnum, remove_dead_code)
 		{
 		  if (REG_NOTE_KIND (inote) == REG_LABEL)
 		    {
+		      int n_forced;
 		      rtx label = XEXP (inote, 0);
 		      rtx next;
 		      LABEL_NUSES (label)--;
 
+		      /* The label may be forced if it has been put in the
+		         constant pool.  We can't delete it in this case, but
+		         we still must discard a jump table following it.  */
+		      n_forced = 0;
+		      if (LABEL_PRESERVE_P (label))
+			n_forced++;
+
 		      /* If this label was attached to an ADDR_VEC, it's
 			 safe to delete the ADDR_VEC.  In fact, it's pretty much
 			 mandatory to delete it, because the ADDR_VEC may
 			 be referencing labels that no longer exist.  */
-		      if (LABEL_NUSES (label) == 0
+		      if (LABEL_NUSES (label) == n_forced
 			  && (next = next_nonnote_insn (label)) != NULL
 			  && GET_CODE (next) == JUMP_INSN
 			  && (GET_CODE (PATTERN (next)) == ADDR_VEC
diff --git a/gcc/jump.c b/gcc/jump.c
index 32eebd1eb6c0..68f967382ed1 100644
--- a/gcc/jump.c
+++ b/gcc/jump.c
@@ -200,8 +200,6 @@ jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, mark_labels_only)
   if (flag_exceptions && cross_jump)
     init_insn_eh_region (f, max_uid);
 
-  delete_barrier_successors (f);
-
   /* Leave some extra room for labels and duplicate exit test insns
      we make.  */
   max_jump_chain = max_uid * 14 / 10;
@@ -224,6 +222,8 @@ jump_optimize_1 (f, cross_jump, noop_moves, after_regscan, mark_labels_only)
   for (insn = exception_handler_labels; insn; insn = XEXP (insn, 1))
     LABEL_NUSES (XEXP (insn, 0))++;
 
+  delete_barrier_successors (f);
+
   /* Quit now if we just wanted to rebuild the JUMP_LABEL and REG_LABEL
      notes and recompute LABEL_NUSES.  */
   if (mark_labels_only)
@@ -2139,7 +2139,23 @@ delete_barrier_successors (f)
 	  insn = NEXT_INSN (insn);
 	  while (insn != 0 && GET_CODE (insn) != CODE_LABEL)
 	    {
-	      if (GET_CODE (insn) == NOTE
+	      if (GET_CODE (insn) == JUMP_INSN)
+		{
+		  /* Detect when we're deleting a tablejump; get rid of
+		     the jump table as well.  */
+		  rtx next1 = next_nonnote_insn (insn);
+		  rtx next2 = next1 ? next_nonnote_insn (next1) : 0;
+		  if (next2 && GET_CODE (next1) == CODE_LABEL
+		      && (GET_CODE (PATTERN (next2)) == ADDR_VEC
+			  || GET_CODE (PATTERN (next2)) == ADDR_DIFF_VEC))
+		    {
+		      delete_insn (insn);
+		      insn = next2;
+		    }
+		  else
+		    insn = delete_insn (insn);
+		}
+	      else if (GET_CODE (insn) == NOTE
 		  && NOTE_LINE_NUMBER (insn) != NOTE_INSN_FUNCTION_END)
 		insn = NEXT_INSN (insn);
 	      else
diff --git a/gcc/varasm.c b/gcc/varasm.c
index b93506546bcf..e5df1d8b52fe 100644
--- a/gcc/varasm.c
+++ b/gcc/varasm.c
@@ -3495,6 +3495,9 @@ force_const_mem (mode, x)
 	  pop_obstacks ();
 	}
 
+      if (GET_CODE (x) == LABEL_REF)
+	LABEL_PRESERVE_P (XEXP (x, 0)) = 1;
+
       /* Allocate a pool constant descriptor, fill it in, and chain it in.  */
 
       pool = (struct pool_constant *) savealloc (sizeof (struct pool_constant));