flow.c (EH_USES): Provide default.

        * flow.c (EH_USES): Provide default.
        (calculate_global_regs_live): Use it for EH edges and noreturn calls.
        * doc/tm.texi (EH_USES): New.

        * config/ia64/ia64.c (ia64_eh_uses): New.
        * config/ia64/ia64-protos.h: Update.
        * config/ia64/ia64.h (EH_USES): New.

From-SVN: r51060

gcc/ChangeLog

 2002-03-19  Richard Henderson  <rth@redhat.com>
 
+	* flow.c (EH_USES): Provide default.
+	(calculate_global_regs_live): Use it for EH edges and noreturn calls.
+	* doc/tm.texi (EH_USES): New.
+
+	* config/ia64/ia64.c (ia64_eh_uses): New.
+	* config/ia64/ia64-protos.h: Update.
+	* config/ia64/ia64.h (EH_USES): New.
+
+2002-03-19  Richard Henderson  <rth@redhat.com>
+
 	* varasm.c (output_constant_def): Fix stupid typo.
 
 2002-03-19  Richard Henderson  <rth@redhat.com>

gcc/config/ia64/ia64-protos.h

@@ -122,6 +122,7 @@ extern void ia64_encode_section_info PARAMS((tree, int));
 extern int ia64_register_move_cost PARAMS((enum machine_mode, enum reg_class,
 					   enum reg_class));
 extern int ia64_epilogue_uses PARAMS((int));
+extern int ia64_eh_uses PARAMS((int));
 extern void emit_safe_across_calls PARAMS((FILE *));
 extern void ia64_init_builtins PARAMS((void));
 extern void ia64_override_options PARAMS((void));

gcc/config/ia64/ia64.c

@@ -6816,6 +6816,34 @@ ia64_epilogue_uses (regno)
       return 0;
     }
 }
+
+/* Return true if REGNO is used by the frame unwinder.  */
+
+int
+ia64_eh_uses (regno)
+     int regno;
+{
+  if (! reload_completed)
+    return 0;
+
+  if (current_frame_info.reg_save_b0
+      && regno == current_frame_info.reg_save_b0)
+    return 1;
+  if (current_frame_info.reg_save_pr
+      && regno == current_frame_info.reg_save_pr)
+    return 1;
+  if (current_frame_info.reg_save_ar_pfs
+      && regno == current_frame_info.reg_save_ar_pfs)
+    return 1;
+  if (current_frame_info.reg_save_ar_unat
+      && regno == current_frame_info.reg_save_ar_unat)
+    return 1;
+  if (current_frame_info.reg_save_ar_lc
+      && regno == current_frame_info.reg_save_ar_lc)
+    return 1;
+
+  return 0;
+}
 
 /* For ia64, SYMBOL_REF_FLAG set means that it is a function.
 

gcc/config/ia64/ia64.h

@@ -1406,6 +1406,10 @@ do {									\
 
 #define EPILOGUE_USES(REGNO) ia64_epilogue_uses (REGNO)
 
+/* Nonzero for registers used by the exception handling mechanism.  */
+
+#define EH_USES(REGNO) ia64_eh_uses (REGNO)
+
 /* Output at beginning of assembler file.  */
 
 #define ASM_FILE_START(FILE) \

gcc/doc/tm.texi

@@ -4042,6 +4042,12 @@ Define this macro as a C expression that is nonzero for registers that are
 used by the epilogue or the @samp{return} pattern.  The stack and frame
 pointer registers are already be assumed to be used as needed.
 
+@findex EH_USES
+@item EH_USES (@var{regno})
+Define this macro as a C expression that is nonzero for registers that are
+used by the exception handling mechanism, and so should be considered live
+on entry to an exception edge.
+
 @findex DELAY_SLOTS_FOR_EPILOGUE
 @item DELAY_SLOTS_FOR_EPILOGUE
 Define this macro if the function epilogue contains delay slots to which

gcc/flow.c

@@ -167,6 +167,9 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA
 #ifndef EPILOGUE_USES
 #define EPILOGUE_USES(REGNO)  0
 #endif
+#ifndef EH_USES
+#define EH_USES(REGNO)  0
+#endif
 
 #ifdef HAVE_conditional_execution
 #ifndef REVERSE_CONDEXEC_PREDICATES_P
@@ -1144,21 +1147,40 @@ calculate_global_regs_live (blocks_in, blocks_out, flags)
 
       /* Begin by propagating live_at_start from the successor blocks.  */
       CLEAR_REG_SET (new_live_at_end);
-      for (e = bb->succ; e; e = e->succ_next)
-	{
-	  basic_block sb = e->dest;
 
-	  /* 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);
+      if (bb->succ)
+	for (e = bb->succ; e; e = e->succ_next)
+	  {
+	    basic_block sb = e->dest;
+
+	    /* 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);
+
+	    /* If a target saves one register in another (instead of on
+	       the stack) the save register will need to be live for EH.  */
+	    if (e->flags & EDGE_EH)
+	      for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+		if (EH_USES (i))
+		  SET_REGNO_REG_SET (new_live_at_end, i);
+	  }
+      else
+	{
+	  /* This might be a noreturn function that throws.  And
+	     even if it isn't, getting the unwind info right helps
+	     debugging.  */
+	  for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
+	    if (EH_USES (i))
+	      SET_REGNO_REG_SET (new_live_at_end, i);
 	}
 
       /* The all-important stack pointer must always be live.  */