re PR rtl-optimization/49994 (ICE: in maybe_record_trace_start, at…

re PR rtl-optimization/49994 (ICE: in maybe_record_trace_start, at dwarf2cfi.c:2234 with -fsched2-use-superblocks)

PR rtl-opt/49994
        * sched-init.h (struct deps_desc): Add sched_before_next_jump.
        * sched-deps.c (init_deps): Clear it.
        (deps_analyze_insn): Consume it.
        (sched_analyze_insn): Fill it.

From-SVN: r177721

gcc/ChangeLog

+2011-08-12  Richard Henderson  <rth@redhat.com>
+
+	PR rtl-opt/49994
+	* sched-init.h (struct deps_desc): Add sched_before_next_jump.
+	* sched-deps.c (init_deps): Clear it.
+	(deps_analyze_insn): Consume it.
+	(sched_analyze_insn): Fill it.
+
 2011-08-12  Ramana Radhakrishnan  <ramana.radhakrishnan@linaro.org>
 
         PR target/48328

gcc/sched-deps.c

@@ -2696,6 +2696,18 @@ sched_analyze_insn (struct deps_desc *deps, rtx x, rtx insn)
     add_dependence_list (insn, deps->last_function_call_may_noreturn,
 			 1, REG_DEP_ANTI);
 
+  /* We must avoid creating a situation in which two successors of the
+     current block have different unwind info after scheduling.  If at any
+     point the two paths re-join this leads to incorrect unwind info.  */
+  /* ??? There are certain situations involving a forced frame pointer in
+     which, with extra effort, we could fix up the unwind info at a later
+     CFG join.  However, it seems better to notice these cases earlier
+     during prologue generation and avoid marking the frame pointer setup
+     as frame-related at all.  */
+  if (RTX_FRAME_RELATED_P (insn))
+    deps->sched_before_next_jump
+      = alloc_INSN_LIST (insn, deps->sched_before_next_jump);
+
   if (code == COND_EXEC)
     {
       sched_analyze_2 (deps, COND_EXEC_TEST (x), insn);
@@ -3302,12 +3314,11 @@ deps_analyze_insn (struct deps_desc *deps, rtx insn)
   if (NONDEBUG_INSN_P (insn))
     sched_get_condition_with_rev (insn, NULL);
 
-  if (NONJUMP_INSN_P (insn) || DEBUG_INSN_P (insn) || JUMP_P (insn))
+  if (JUMP_P (insn))
     {
       /* Make each JUMP_INSN (but not a speculative check)
          a scheduling barrier for memory references.  */
       if (!deps->readonly
-          && JUMP_P (insn)
           && !(sel_sched_p ()
                && sel_insn_is_speculation_check (insn)))
         {
@@ -3326,6 +3337,15 @@ deps_analyze_insn (struct deps_desc *deps, rtx insn)
 	    }
         }
 
+      /* For each insn which shouldn't cross a jump, add a dependence.  */
+      add_dependence_list_and_free (deps, insn,
+				    &deps->sched_before_next_jump, 1,
+				    REG_DEP_ANTI);
+
+      sched_analyze_insn (deps, PATTERN (insn), insn);
+    }
+  else if (NONJUMP_INSN_P (insn) || DEBUG_INSN_P (insn))
+    {
       sched_analyze_insn (deps, PATTERN (insn), insn);
     }
   else if (CALL_P (insn))
@@ -3571,6 +3591,7 @@ init_deps (struct deps_desc *deps, bool lazy_reg_last)
   deps->last_function_call = 0;
   deps->last_function_call_may_noreturn = 0;
   deps->sched_before_next_call = 0;
+  deps->sched_before_next_jump = 0;
   deps->in_post_call_group_p = not_post_call;
   deps->last_debug_insn = 0;
   deps->last_reg_pending_barrier = NOT_A_BARRIER;

gcc/sched-int.h

@@ -496,6 +496,9 @@ struct deps_desc
      scheduling is done.  */
   rtx sched_before_next_call;
 
+  /* Similarly, a list of insns which should not cross a branch.  */
+  rtx sched_before_next_jump;
+
   /* Used to keep post-call pseudo/hard reg movements together with
      the call.  */
   enum post_call_group in_post_call_group_p;

gcc/testsuite/gcc.dg/pr49994-1.c

+/* { dg-do compile } */
+/* { dg-options "-Os -fsched2-use-superblocks -g" } */
+
+void x (int a)
+{
+  __label__ xlab;
+  void y (int b)
+  {
+    switch (b)
+      {
+      case 1:
+	goto xlab;
+      case 2:
+	goto xlab;
+      }
+  }
+  y (a);
+xlab:;
+}

gcc/testsuite/gcc.dg/pr49994-2.c

+/* { dg-do compile } */
+/* { dg-options "-O -fno-omit-frame-pointer -fschedule-insns2 -fsched2-use-superblocks -g" } */
+
+int
+bar (int i)
+{
+  while (i)
+    if (i)
+      return i;
+}
+
+void
+foo ()
+{
+  bar (0);
+}

gcc/testsuite/gcc.dg/pr49994-3.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -fsched2-use-superblocks -g" } */
+
+void *
+foo (int offset)
+{
+  switch (offset)
+    {
+    case 0:
+      return __builtin_return_address (0);
+    case 1:
+      return __builtin_return_address (1);
+    case 2:
+      return __builtin_return_address (2);
+    case 3:
+      return __builtin_return_address (3);
+    case 4:
+      return __builtin_return_address (4);
+    }
+  return 0;
+}