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[PATCH] prevents labels referenced in the exception table to be deleted


While running validations on the SH for PR target/42841, we found an issue with undefined labels, that happened to be landing pad entries deleted by reorg_redirect_jump.

The situation was that we had sh_reorg inserting a constant pool just
bellow a barrier, which happens to be before a landing pad (whose first
instruction was a jump), and creates a jump over the constant pool. Then reorg_redirect_jump (from dbr), deletes the label despite its reference in the exception table.

A label referenced in the exception table is not dead and should not be
deleted when jumps are merged, This patch just prevents this.



2010-02-10  Christian Bruel  <>

	* except.c (eh_landing_pad_p): New function.
	* except.h (eh_landing_pad_p): Declare.
	* jump.c (redirect_jump_2): Check if label is a landing pad.

Index: jump.c
--- jump.c	(revision 156449)
+++ jump.c	(working copy)
@@ -1485,7 +1485,8 @@
   if (olabel && --LABEL_NUSES (olabel) == 0 && delete_unused > 0
       /* Undefined labels will remain outside the insn stream.  */
-      && INSN_UID (olabel))
+      && INSN_UID (olabel)
+      && !eh_landing_pad_p (olabel))
     delete_related_insns (olabel);
   if (invert)
     invert_br_probabilities (jump);
Index: except.c
--- except.c	(revision 156449)
+++ except.c	(working copy)
@@ -455,6 +455,22 @@
   return lp;
+eh_landing_pad_p (rtx lab)
+  int n = VEC_length (eh_landing_pad, cfun->eh->lp_array);
+  int i;
+  for (i = 0; i < n; ++i)
+    {
+      eh_landing_pad lp = VEC_index (eh_landing_pad, cfun->eh->lp_array, i);
+      if (lp && lp->landing_pad == lab)
+	  return true;
+    }
+  return false;
 get_eh_region_from_number_fn (struct function *ifun, int i)
Index: except.h
--- except.h	(revision 156449)
+++ except.h	(working copy)
@@ -297,6 +297,8 @@
 /* Return true if type A catches type B.  */
 extern int (*lang_eh_type_covers) (tree a, tree b);
+/* Return true if label l is a landing pad.  */
+bool eh_landing_pad_p (rtx l);
 /* Just because the user configured --with-sjlj-exceptions=no doesn't
    mean that we can use call frame exceptions.  Detect that the target

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