From 6ce54e9665788e6a172950c68fb58158e923c6ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20L=C3=A5ng?= <margnus1@telia.com>
Date: Mon, 14 Nov 2016 15:31:28 +0100
Subject: hipe_icode: Always const-propagate if&call args

---
 lib/hipe/icode/hipe_icode.erl                |  4 +++
 lib/hipe/icode/hipe_icode_ssa_const_prop.erl | 43 ++++++++++++++++------------
 2 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/lib/hipe/icode/hipe_icode.erl b/lib/hipe/icode/hipe_icode.erl
index dce2fcb392..d2d08e0253 100644
--- a/lib/hipe/icode/hipe_icode.erl
+++ b/lib/hipe/icode/hipe_icode.erl
@@ -438,6 +438,7 @@
 	 if_true_label/1,
 	 if_false_label/1,
 	 if_args/1,
+	 if_args_update/2,
 	 if_pred/1,
 	 %% is_if/1,
 	 
@@ -714,6 +715,9 @@ if_op_update(IF, NewOp) -> IF#icode_if{op=NewOp}.
 -spec if_args(#icode_if{}) -> [icode_term_arg()].
 if_args(#icode_if{args=Args}) -> Args.
 
+-spec if_args_update(#icode_if{}, [icode_term_arg()]) -> #icode_if{}.
+if_args_update(IF, Args) -> IF#icode_if{args=Args}.
+
 -spec if_true_label(#icode_if{}) -> icode_lbl().
 if_true_label(#icode_if{true_label=TrueLbl}) -> TrueLbl.
 
diff --git a/lib/hipe/icode/hipe_icode_ssa_const_prop.erl b/lib/hipe/icode/hipe_icode_ssa_const_prop.erl
index 4ab4d7e95d..5d3d5413bc 100644
--- a/lib/hipe/icode/hipe_icode_ssa_const_prop.erl
+++ b/lib/hipe/icode/hipe_icode_ssa_const_prop.erl
@@ -97,11 +97,13 @@ visit_expression(Instruction, Environment) ->
       visit_begin_handler     (Instruction, EvaluatedArguments, Environment);
     #icode_begin_try{} ->
       visit_begin_try         (Instruction, EvaluatedArguments, Environment);
-    #icode_fail{} ->                
+    #icode_fail{} ->
       visit_fail              (Instruction, EvaluatedArguments, Environment);
-    _ ->
-      %% label, end_try, comment, return,
-      {[], [], Environment}
+    #icode_comment{} -> {[], [], Environment};
+    #icode_end_try{} -> {[], [], Environment};
+    #icode_enter{} ->   {[], [], Environment};
+    #icode_label{} ->   {[], [], Environment};
+    #icode_return{} ->  {[], [], Environment}
   end.
 
 %%-----------------------------------------------------------------------------
@@ -463,11 +465,15 @@ update_instruction(Instruction, Environment) ->
       update_type(Instruction, Environment);
     #icode_switch_tuple_arity{} ->
       update_switch_tuple_arity(Instruction, Environment);
-    _ ->
-      %% goto, comment, label, return, begin_handler, end_try,
-      %% begin_try, fail
-      %% We could but don't handle: catch?, fail?
-      [Instruction]
+    %% We could but don't handle: catch?, fail?
+    #icode_begin_handler{} -> [Instruction];
+    #icode_begin_try{} ->     [Instruction];
+    #icode_comment{} ->       [Instruction];
+    #icode_end_try{} ->       [Instruction];
+    #icode_fail{} ->          [Instruction];
+    #icode_goto{} ->          [Instruction];
+    #icode_label{} ->         [Instruction];
+    #icode_return{} ->        [Instruction]
   end.
 
 %%-----------------------------------------------------------------------------
@@ -502,14 +508,12 @@ update_call(Instruction, Environment) ->
 			  [Instruction, NewInstructions]),
 	  NewInstructions
       end;
-%%     %% [] ->  %% No destination; we don't touch this
-%%     [] -> 
-%%       NewArguments = update_arguments(hipe_icode:call_args(Instruction),
-%%                                       Environment),
-%%       [hipe_icode:call_args_update(Instruction, NewArguments)];
+    %% [] ->  %% No destination; we don't touch this
     %% List-> %% Means register allocation; not implemented at this point
     _ ->
-      [Instruction]
+      NewArguments = update_arguments(hipe_icode:call_args(Instruction),
+                                      Environment),
+      [hipe_icode:call_args_update(Instruction, NewArguments)]
   end.
 
 %%-----------------------------------------------------------------------------
@@ -574,7 +578,9 @@ update_if(Instruction, Environment) ->
       %% Convert the if-test to a type test if possible.
       Op = hipe_icode:if_op(Instruction),
       case Op =:= '=:=' orelse Op =:= '=/=' of
-	false -> [Instruction];
+	false ->
+	  [hipe_icode:if_args_update(
+	     Instruction, update_arguments(Args, Environment))];
 	true ->
 	  [Arg1, Arg2] = Args,
 	  case EvaluatedArguments of
@@ -604,8 +610,9 @@ conv_if_to_type(I, Const, Arg) when is_atom(Const);
   NewI = hipe_icode:mk_type([Arg], Test, T, F),
   ?CONST_PROP_MSG("if: ~w ---> type ~w\n", [I, NewI]),
   [NewI];
-conv_if_to_type(I, _, _) ->
-  [I].
+conv_if_to_type(I, Const, Arg) ->
+  %% Note: we are potentially commuting the (equality) comparison here
+  [hipe_icode:if_args_update(I, [Arg, hipe_icode:mk_const(Const)])].
 
 %%-----------------------------------------------------------------------------
 
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