[PATCH] Fix -fprofile-use optimization of a noreturn indirect call (PR gcov-profile/49299)

[Jakub Jelinek]

Hi!

When an indirect noreturn call has a likely call target, value-prof.c
ICEs on it, as there is no fallthru edge after the call (nor a join bb).
Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
ok for trunk/4.6?

2011-06-06  Jakub Jelinek  <ja...@redhat.com>

        PR gcov-profile/49299
        * value-prof.c (gimple_ic): Don't assume icall has
        a fallthru edge.

        * gcc.dg/tree-prof/pr49299-1.c: New test.
        * gcc.dg/tree-prof/pr49299-2.c: New test.

--- gcc/value-prof.c.jj 2011-05-02 18:39:28.000000000 +0200
+++ gcc/value-prof.c    2011-06-06 12:37:30.000000000 +0200
@@ -1145,9 +1145,9 @@ gimple_ic (gimple icall_stmt, struct cgr
 {
   gimple dcall_stmt, load_stmt, cond_stmt;
   tree tmp0, tmp1, tmpv, tmp;
-  basic_block cond_bb, dcall_bb, icall_bb, join_bb;
+  basic_block cond_bb, dcall_bb, icall_bb, join_bb = NULL;
   tree optype = build_pointer_type (void_type_node);
-  edge e_cd, e_ci, e_di, e_dj, e_ij;
+  edge e_cd, e_ci, e_di, e_dj = NULL, e_ij;
   gimple_stmt_iterator gsi;
   int lp_nr;
 
@@ -1194,12 +1194,19 @@ gimple_ic (gimple icall_stmt, struct cgr
   else
     {
       e_ij = find_fallthru_edge (icall_bb->succs);
-      e_ij->probability = REG_BR_PROB_BASE;
-      e_ij->count = all - count;
-      e_ij = single_pred_edge (split_edge (e_ij));
+      /* The indirect call might be noreturn.  */
+      if (e_ij != NULL)
+       {
+         e_ij->probability = REG_BR_PROB_BASE;
+         e_ij->count = all - count;
+         e_ij = single_pred_edge (split_edge (e_ij));
+       }
+    }
+  if (e_ij != NULL)
+    {
+      join_bb = e_ij->dest;
+      join_bb->count = all;
     }
-  join_bb = e_ij->dest;
-  join_bb->count = all;
 
   e_cd->flags = (e_cd->flags & ~EDGE_FALLTHRU) | EDGE_TRUE_VALUE;
   e_cd->probability = prob;
@@ -1211,12 +1218,15 @@ gimple_ic (gimple icall_stmt, struct cgr
 
   remove_edge (e_di);
 
-  e_dj = make_edge (dcall_bb, join_bb, EDGE_FALLTHRU);
-  e_dj->probability = REG_BR_PROB_BASE;
-  e_dj->count = count;
+  if (e_ij != NULL)
+    {
+      e_dj = make_edge (dcall_bb, join_bb, EDGE_FALLTHRU);
+      e_dj->probability = REG_BR_PROB_BASE;
+      e_dj->count = count;
 
-  e_ij->probability = REG_BR_PROB_BASE;
-  e_ij->count = all - count;
+      e_ij->probability = REG_BR_PROB_BASE;
+      e_ij->count = all - count;
+    }
 
   /* Insert PHI node for the call result if necessary.  */
   if (gimple_call_lhs (icall_stmt)
--- gcc/testsuite/gcc.dg/tree-prof/pr49299-1.c.jj       2011-06-06 
11:34:58.000000000 +0200
+++ gcc/testsuite/gcc.dg/tree-prof/pr49299-1.c  2011-06-06 11:34:51.000000000 
+0200
@@ -0,0 +1,34 @@
+/* { dg-options "-O2" } */
+
+__attribute__((noreturn)) void (*fn) (void);
+
+volatile int v;
+
+__attribute__((noreturn)) void
+fn0 (void)
+{
+  __builtin_exit (0);
+}
+
+__attribute__((noreturn)) void
+fn1 (void)
+{
+  __builtin_exit (1);
+}
+
+__attribute__((noinline, noclone)) void
+setfn (__attribute__((noreturn)) void (*x) (void))
+{
+  fn = x;
+}
+
+int
+main ()
+{
+  int i;
+  if (v < 1)
+    setfn (fn0);
+  else
+    setfn (fn1);
+  fn ();
+}
--- gcc/testsuite/gcc.dg/tree-prof/pr49299-2.c.jj       2011-06-06 
12:46:25.000000000 +0200
+++ gcc/testsuite/gcc.dg/tree-prof/pr49299-2.c  2011-06-06 12:39:15.000000000 
+0200
@@ -0,0 +1,34 @@
+/* { dg-options "-O2" } */
+
+void (*fn) (void);
+
+volatile int v;
+
+__attribute__((noreturn)) void
+fn0 (void)
+{
+  __builtin_exit (0);
+}
+
+void
+fn1 (void)
+{
+}
+
+__attribute__((noinline, noclone)) void
+setfn (void (*x) (void))
+{
+  fn = x;
+}
+
+int
+main ()
+{
+  int i;
+  if (v < 1)
+    setfn (fn0);
+  else
+    setfn (fn1);
+  fn ();
+  return 0;
+}

        Jakub