Merge PR-1392 from margnus1/hipe-range-fixpoint-bug OTP-14306

HiPE: Fix ERL-278: Fix range analysis miscompilation bug

3 files changed, 54 insertions, 13 deletions

diff --git a/lib/hipe/cerl/erl_bif_types.erl b/lib/hipe/cerl/erl_bif_types.erl
index 8c96e60229..9321750d44 100644
--- a/lib/hipe/cerl/erl_bif_types.erl
+++ b/lib/hipe/cerl/erl_bif_types.erl
@@ -2029,17 +2029,14 @@ arith_rem(Min1, Max1, Min2, Max2) ->
   Min1_geq_zero = infinity_geq(Min1, 0),
   Max1_leq_zero = infinity_geq(0, Max1),
   Max_range2 = infinity_max([infinity_abs(Min2), infinity_abs(Max2)]),
-  Max_range2_leq_zero = infinity_geq(0, Max_range2),
-  New_min = 
+  New_min =
     if Min1_geq_zero -> 0;
        Max_range2 =:= 0 -> 0;
-       Max_range2_leq_zero -> infinity_add(Max_range2, 1);
        true -> infinity_add(infinity_inv(Max_range2), 1)
     end,
   New_max = 
     if Max1_leq_zero -> 0;
        Max_range2 =:= 0 -> 0;
-       Max_range2_leq_zero -> infinity_add(infinity_inv(Max_range2), -1);
        true -> infinity_add(Max_range2, -1)
     end,
   {New_min, New_max}.
diff --git a/lib/hipe/icode/hipe_icode_range.erl b/lib/hipe/icode/hipe_icode_range.erl
index b884132327..287b1c80fe 100644
--- a/lib/hipe/icode/hipe_icode_range.erl
+++ b/lib/hipe/icode/hipe_icode_range.erl
@@ -392,14 +392,17 @@ widen(#range{range=Old}, #range{range=New}, T = #range{range=Wide}) ->
 -spec analyse_call(#icode_call{}, call_fun()) -> #icode_call{}.
 
 analyse_call(Call, LookupFun) ->
+  Args = hipe_icode:args(Call),
+  Fun = hipe_icode:call_fun(Call),
+  Type = hipe_icode:call_type(Call),
+  %% This call has side-effects (it might call LookupFun which sends messages to
+  %% hipe_icode_coordinator to update the argument ranges of Fun), and must thus
+  %% not be moved into the case statement.
+  DstRanges = analyse_call_or_enter_fun(Fun, Args, Type, LookupFun),
   case hipe_icode:call_dstlist(Call) of
     [] ->
       Call;
     Dsts ->
-      Args = hipe_icode:args(Call),
-      Fun = hipe_icode:call_fun(Call),
-      Type = hipe_icode:call_type(Call),
-      DstRanges = analyse_call_or_enter_fun(Fun, Args, Type, LookupFun),
       NewDefs = [update_info(Var, R) || {Var,R} <- lists:zip(Dsts, DstRanges)],
       hipe_icode:subst_defines(lists:zip(Dsts, NewDefs), Call)
   end.
@@ -1306,16 +1309,15 @@ range_rem(Range1, Range2) ->
   Min1_geq_zero = inf_geq(Min1, 0),
   Max1_leq_zero = inf_geq(0, Max1),
   Max_range2 = inf_max([inf_abs(Min2), inf_abs(Max2)]),
-  Max_range2_leq_zero = inf_geq(0, Max_range2),
   New_min = 
     if Min1_geq_zero ->	0;
-       Max_range2_leq_zero -> Max_range2;
-       true -> inf_inv(Max_range2)
+       Max_range2 =:= 0 -> 0;
+       true -> inf_add(inf_inv(Max_range2), 1)
     end,
   New_max = 
     if Max1_leq_zero -> 0;
-       Max_range2_leq_zero -> inf_inv(Max_range2);
-       true -> Max_range2
+       Max_range2 =:= 0 -> 0;
+       true -> inf_add(Max_range2, -1)
     end,
   range_init({New_min, New_max}, false).
 
diff --git a/lib/hipe/test/basic_SUITE_data/basic_bugs_hipe.erl b/lib/hipe/test/basic_SUITE_data/basic_bugs_hipe.erl
index caa0e71d0b..430e097b91 100644
--- a/lib/hipe/test/basic_SUITE_data/basic_bugs_hipe.erl
+++ b/lib/hipe/test/basic_SUITE_data/basic_bugs_hipe.erl
@@ -18,6 +18,7 @@ test() ->
   ok = test_R12B5_seg_fault(),
   ok = test_switch_neg_int(),
   ok = test_icode_range_anal(),
+  ok = test_icode_range_call(),
   ok.
 
 %%-----------------------------------------------------------------------
@@ -461,3 +462,44 @@ g(X, Z) ->
     test -> non_zero_test;
     other -> other
   end.
+
+%%-----------------------------------------------------------------------
+%% From: Rich Neswold
+%% Date: Oct 5, 2016
+%%
+%% The following was a bug in the HiPE compiler's range analysis. The
+%% function range_client/2 below would would not stop when N reached 0,
+%% but keep recursing into the second clause forever.
+%%
+%% The problem turned out to be in hipe_icode_range:analyse_call/2,
+%% which would note update the argument ranges of the callee if the
+%% result of the call was ignored.
+%% -----------------------------------------------------------------------
+-define(TIMEOUT, 42).
+
+test_icode_range_call() ->
+    Self = self(),
+    Client = spawn_link(fun() -> range_client(Self, 4) end),
+    range_server(4, Client).
+
+range_server(0, _Client) ->
+    receive
+        stopping -> ok;
+        {called_with, 0} -> error(failure)
+    after ?TIMEOUT -> error(timeout)
+    end;
+range_server(N, Client) ->
+    receive
+        {called_with, N} ->
+            Client ! proceed
+    after ?TIMEOUT -> error(timeout)
+    end,
+    range_server(N-1, Client). % tailcall (so the bug does not affect it)
+
+range_client(Server, 0) ->
+    Server ! stopping;
+range_client(Server, N) ->
+    Server ! {called_with, N},
+    receive proceed -> ok end,
+    range_client(Server, N - 1), % non-tailrecursive call with ignored result
+    ok.