re PR rtl-optimization/81290 (ICE in update_br_prob_note)

	PR middle-end/81290
	* predict.c (force_edge_cold): Be more careful about propagation
	backward.
	* profile-count.h (profile_probability::guessed,
	profile_probability::fdo, profile_count::guessed, profile_count::fdo):
	New.
	* tree-ssa-threadupdate.c (recompute_probabilities): Result is guessed.

	* gcc.c-torture/compile/pr81290.c: New.

From-SVN: r249924

gcc/ChangeLog

+2017-07-02  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR middle-end/81290
+	* predict.c (force_edge_cold): Be more careful about propagation
+	backward.
+	* profile-count.h (profile_probability::guessed,
+	profile_probability::fdo, profile_count::guessed, profile_count::fdo):
+	New.
+	* tree-ssa-threadupdate.c (recompute_probabilities): Result is guessed.
+
 2017-07-03  James Greenhalgh  <james.greenhalgh@arm.com>
 
 	* doc/invoke.texi (rcpc architecture extension): Document it.

gcc/predict.c

@@ -3962,15 +3962,26 @@ force_edge_cold (edge e, bool impossible)
 	      e2->count.apply_scale (count_sum2, count_sum);
 	    e2->probability /= prob_comp;
 	  }
-      if (current_ir_type () != IR_GIMPLE)
+      if (current_ir_type () != IR_GIMPLE
+	  && e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
 	update_br_prob_note (e->src);
     }
   /* If all edges out of e->src are unlikely, the basic block itself
      is unlikely.  */
   else
     {
-      e->probability = profile_probability::always ();
-      if (current_ir_type () != IR_GIMPLE)
+      if (prob_sum == profile_probability::never ())
+        e->probability = profile_probability::always ();
+      else
+	{
+	  if (impossible)
+	    e->probability = profile_probability::never ();
+	  /* If BB has some edges out that are not impossible, we can not
+	     assume that BB itself is.  */
+	  impossible = false;
+	}
+      if (current_ir_type () != IR_GIMPLE
+	  && e->src != ENTRY_BLOCK_PTR_FOR_FN (cfun))
 	update_br_prob_note (e->src);
       if (e->src->count == profile_count::zero ())
 	return;

gcc/profile-count.h

@@ -351,6 +351,22 @@ public:
       return profile_probability::always() - *this;
     }
 
+  /* Return THIS with quality dropped to GUESSED.  */
+  profile_probability guessed () const
+    {
+      profile_probability ret = *this;
+      ret.m_quality = profile_guessed;
+      return ret;
+    }
+
+  /* Return THIS with quality dropped to AFDO.  */
+  profile_probability afdo () const
+    {
+      profile_probability ret = *this;
+      ret.m_quality = profile_afdo;
+      return ret;
+    }
+
   profile_probability combine_with_freq (int freq1, profile_probability other,
 					 int freq2) const
     {
@@ -767,6 +783,22 @@ public:
       return ret;
     }
 
+  /* Return THIS with quality dropped to GUESSED.  */
+  profile_count guessed () const
+    {
+      profile_count ret = *this;
+      ret.m_quality = profile_guessed;
+      return ret;
+    }
+
+  /* Return THIS with quality dropped to AFDO.  */
+  profile_count afdo () const
+    {
+      profile_count ret = *this;
+      ret.m_quality = profile_afdo;
+      return ret;
+    }
+
   /* Return probability of event with counter THIS within event with counter
      OVERALL.  */
   profile_probability probability_in (const profile_count overall) const

gcc/testsuite/ChangeLog

+2017-07-02  Jan Hubicka  <hubicka@ucw.cz>
+
+	PR middle-end/81290
+	* gcc.c-torture/compile/pr81290.c: New.
+
 2017-07-03  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/60510

gcc/testsuite/gcc.c-torture/compile/pr81290.c

+/* { dg-options "-funroll-loops -w" } */
+int vz;
+
+void
+ms (int sw, int cm)
+{
+  for (vz = 0; vz < 19; ++vz)
+    {
+ fx:
+      sw *= 2;
+    }
+
+  for (;;)
+    {
+      if (sw != 0)
+        for (;;)
+          {
+          }
+      if (1 / 0 && cm != 0)
+        goto fx;
+    }
+}

gcc/tree-ssa-threadupdate.c

@@ -908,7 +908,7 @@ recompute_probabilities (basic_block bb)
 
       /* Prevent overflow computation due to insane profiles.  */
       if (esucc->count < bb->count)
-	esucc->probability = esucc->count.probability_in (bb->count);
+	esucc->probability = esucc->count.probability_in (bb->count).guessed ();
       else
 	/* Can happen with missing/guessed probabilities, since we
 	   may determine that more is flowing along duplicated
@@ -1051,7 +1051,8 @@ freqs_to_counts_path (struct redirection_data *rd)
       if (ein->probability.initialized_p ())
         ein->count = profile_count::from_gcov_type
 		  (apply_probability (ein->src->frequency * REG_BR_PROB_BASE,
-				        ein->probability.to_reg_br_prob_base ()));
+				        ein->probability
+					  .to_reg_br_prob_base ())).guessed ();
       else
 	/* FIXME: this is hack; we should track uninitialized values.  */
 	ein->count = profile_count::zero ();