* flow.c (tidy_fallthru_edges): Don't combine complex edges.

        (calculate_global_regs_live): Kill call-clobbered registers
        across exception edges.
        * reg-stack.c (convert_regs_1): Kill the entire target stack
        across non-call exception edges.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@40909 138bc75d-0d04-0410-961f-82ee72b054a4

3 files changed, 37 insertions, 7 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 15a9dd295ad..de13830884d 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -28,6 +28,12 @@
 	* final.c: Don't check it.
 	* except.c: Provide stub definition.
 
+	* flow.c (tidy_fallthru_edges): Don't combine complex edges.
+	(calculate_global_regs_live): Kill call-clobbered registers
+	across exception edges.
+	* reg-stack.c (convert_regs_1): Kill the entire target stack
+	across non-call exception edges.
+
 2001-03-27  Kaveh R. Ghazi  <ghazi@caip.rutgers.edu>
 
 	* configure.in: Don't check for bcopy.
diff --git a/gcc/flow.c b/gcc/flow.c
index bf5043a5e7b..e8bf0400262 100644
--- a/gcc/flow.c
+++ b/gcc/flow.c
@@ -2995,6 +2995,7 @@ tidy_fallthru_edges ()
 	 merge the flags for the duplicate edges.  So we do not want to
 	 check that the edge is not a FALLTHRU edge.  */
       if ((s = b->succ) != NULL
+	  && ! (s->flags & EDGE_COMPLEX)
 	  && s->succ_next == NULL
 	  && s->dest == c
 	  /* If the jump insn has side effects, we can't tidy the edge.  */
@@ -3542,13 +3543,19 @@ calculate_global_regs_live (blocks_in, blocks_out, flags)
      int flags;
 {
   basic_block *queue, *qhead, *qtail, *qend;
-  regset tmp, new_live_at_end;
-  regset_head tmp_head;
+  regset tmp, new_live_at_end, call_used;
+  regset_head tmp_head, call_used_head;
   regset_head new_live_at_end_head;
   int i;
 
   tmp = INITIALIZE_REG_SET (tmp_head);
   new_live_at_end = INITIALIZE_REG_SET (new_live_at_end_head);
+  call_used = INITIALIZE_REG_SET (call_used_head);
+
+  /* Inconveniently, this is only redily available in hard reg set form.  */
+  for (i = 0; i < FIRST_PSEUDO_REGISTER; ++i)
+    if (call_used_regs[i])
+      SET_REGNO_REG_SET (call_used, i);
 
   /* Create a worklist.  Allocate an extra slot for ENTRY_BLOCK, and one
      because the `head == tail' style test for an empty queue doesn't
@@ -3602,7 +3609,18 @@ calculate_global_regs_live (blocks_in, blocks_out, flags)
       for (e = bb->succ; e; e = e->succ_next)
 	{
 	  basic_block sb = e->dest;
-	  IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
+
+	  /* Call-clobbered registers die across exception and call edges.  */
+	  /* ??? Abnormal call edges ignored for the moment, as this gets
+	     confused by sibling call edges, which crashes reg-stack.  */
+	  if (e->flags & EDGE_EH)
+	    {
+	      bitmap_operation (tmp, sb->global_live_at_start,
+				call_used, BITMAP_AND_COMPL);
+	      IOR_REG_SET (new_live_at_end, tmp);
+	    }
+	  else
+	    IOR_REG_SET (new_live_at_end, sb->global_live_at_start);
 	}
 
       /* The all-important stack pointer must always be live.  */
@@ -3750,6 +3768,7 @@ calculate_global_regs_live (blocks_in, blocks_out, flags)
 
   FREE_REG_SET (tmp);
   FREE_REG_SET (new_live_at_end);
+  FREE_REG_SET (call_used);
 
   if (blocks_out)
     {
diff --git a/gcc/reg-stack.c b/gcc/reg-stack.c
index 0e85a5ab922..54c3f086a48 100644
--- a/gcc/reg-stack.c
+++ b/gcc/reg-stack.c
@@ -2553,10 +2553,15 @@ convert_regs_1 (file, block)
 	    }
 	}
 
-      /* Care for EH edges specially.  The normal return path may return
-	 a value in st(0), but the EH path will not, and there's no need
-	 to add popping code to the edge.  */
-      if (e->flags & (EDGE_EH | EDGE_ABNORMAL_CALL))
+      /* Care for non-call EH edges specially.  The normal return path have
+	 values in registers.  These will be popped en masse by the unwind
+	 library.  */
+      if ((e->flags & (EDGE_EH | EDGE_ABNORMAL_CALL)) == EDGE_EH)
+	target_stack->top = -1;
+
+      /* Other calls may appear to have values live in st(0), but the
+	 abnormal return path will not have actually loaded the values.  */
+      else if (e->flags & EDGE_ABNORMAL_CALL)
 	{
 	  /* Assert that the lifetimes are as we expect -- one value
 	     live at st(0) on the end of the source block, and no