hipe_rtl: unify branch and alub

branch and alub overlap in their use cases, but the backends rely on
knowing that the result is unused in their lowering of branch. By
extending alub so that the destination is optional, it can fully replace
branch.

This simplifies rtl by reducing code duplication and the number of
instructions.

Also, in the x86 and arm backends, we can now use 'test' and
{'tst','mvn','teq'} to lower some alubs without destinations. This is
particularly good for x86, as sequences such as 'is_boxed' type tests
now get shorter (both from not needing a mov to copy the variable, but
also from the fact that 'testb' encodes shorter than 'andq').

1 files changed, 18 insertions, 59 deletions

diff --git a/lib/hipe/rtl/hipe_rtl.erl b/lib/hipe/rtl/hipe_rtl.erl
index 0726827299..e4e857ec43 100644
--- a/lib/hipe/rtl/hipe_rtl.erl
+++ b/lib/hipe/rtl/hipe_rtl.erl
@@ -187,18 +187,14 @@
 
 	 mk_branch/5,
 	 mk_branch/6,
-	 branch_src1/1,
-	 branch_src2/1,
-	 branch_cond/1,
-	 branch_true_label/1,
-	 branch_false_label/1,
-	 branch_pred/1,
+	 mk_branch/7,
 	 %% is_branch/1,
 	 %% branch_true_label_update/2,
 	 %% branch_false_label_update/2,
 
 	 mk_alub/7,
 	 mk_alub/8,
+	 alub_has_dst/1,
 	 alub_dst/1,
 	 alub_src1/1,
 	 alub_op/1,
@@ -588,37 +584,25 @@ is_label(#label{}) -> true;
 is_label(_) -> false.
 
 %%
-%% branch
-%%
-
-mk_branch(Src1, Op, Src2, True, False) ->
-  mk_branch(Src1, Op, Src2, True, False, 0.5).
-mk_branch(Src1, Op, Src2, True, False, P) ->
-  #branch{src1=Src1, 'cond'=Op, src2=Src2, true_label=True,
-	  false_label=False, p=P}.
-branch_src1(#branch{src1=Src1}) -> Src1.
-branch_src1_update(Br, NewSrc) -> Br#branch{src1=NewSrc}.
-branch_src2(#branch{src2=Src2}) -> Src2.
-branch_src2_update(Br, NewSrc) -> Br#branch{src2=NewSrc}.
-branch_cond(#branch{'cond'=Cond}) -> Cond.
-branch_true_label(#branch{true_label=TrueLbl}) -> TrueLbl.
-branch_true_label_update(Br, NewTrue) -> Br#branch{true_label=NewTrue}.
-branch_false_label(#branch{false_label=FalseLbl}) -> FalseLbl.
-branch_false_label_update(Br, NewFalse) -> Br#branch{false_label=NewFalse}.
-branch_pred(#branch{p=P}) -> P.
-
-%%
 %% alub
 %%
 
 -type alub_cond() :: 'eq' | 'ne' | 'ge' | 'geu' | 'gt' | 'gtu' | 'le'
                    | 'leu' | 'lt' | 'ltu' | 'overflow' | 'not_overflow'.
 
+mk_branch(Src1, Cond, Src2, True, False) ->
+  mk_branch(Src1, Cond, Src2, True, False, 0.5).
+mk_branch(Src1, Cond, Src2, True, False, P) ->
+  mk_branch(Src1, 'sub', Src2, Cond, True, False, P).
+mk_branch(Src1, Op, Src2, Cond, True, False, P) ->
+  mk_alub([], Src1, Op, Src2, Cond, True, False, P).
+
 mk_alub(Dst, Src1, Op, Src2, Cond, True, False) ->
   mk_alub(Dst, Src1, Op, Src2, Cond, True, False, 0.5).
 mk_alub(Dst, Src1, Op, Src2, Cond, True, False, P) ->
   #alub{dst=Dst, src1=Src1, op=Op, src2=Src2, 'cond'=Cond,
 	true_label=True, false_label=False, p=P}.
+alub_has_dst(#alub{dst=Dst}) -> Dst =/= [].
 alub_dst(#alub{dst=Dst}) -> Dst.
 alub_dst_update(A, NewDst) -> A#alub{dst=NewDst}.
 alub_src1(#alub{src1=Src1}) -> Src1.
@@ -943,8 +927,7 @@ args(I) ->
   case I of
     #alu{} -> [alu_src1(I), alu_src2(I)];
     #alub{} -> [alub_src1(I), alub_src2(I)];
-    #branch{} -> [branch_src1(I), branch_src2(I)];
-    #call{} -> 
+    #call{} ->
       Args = call_arglist(I) ++ hipe_rtl_arch:call_used(),
       case call_is_known(I) of
 	false -> [call_fun(I) | Args];
@@ -987,8 +970,8 @@ args(I) ->
 defines(Instr) ->
   Defs = case Instr of
 	   #alu{} -> [alu_dst(Instr)];
+	   #alub{dst=[]} -> [];
 	   #alub{} -> [alub_dst(Instr)];
-	   #branch{} -> [];
 	   #call{} -> call_dstlist(Instr) ++ hipe_rtl_arch:call_defined();
 	   #comment{} -> [];
 	   #enter{} -> [];
@@ -1042,9 +1025,6 @@ subst_uses(Subst, I) ->
     #alub{} ->
       I0 = alub_src1_update(I, subst1(Subst, alub_src1(I))),
       alub_src2_update(I0, subst1(Subst, alub_src2(I)));
-    #branch{} ->
-      I0 = branch_src1_update(I, subst1(Subst, branch_src1(I))),
-      branch_src2_update(I0, subst1(Subst, branch_src2(I)));
     #call{} ->
       case call_is_known(I) of
 	false ->
@@ -1126,11 +1106,6 @@ subst_uses_llvm(Subst, I) ->
       {NewSrc1, _ } = subst1_llvm(Subst1, alub_src1(I)),
       I0 =  alub_src1_update(I, NewSrc1),
       alub_src2_update(I0, NewSrc2);
-    #branch{} ->
-      {NewSrc2, Subst1} = subst1_llvm(Subst, branch_src2(I)),
-      {NewSrc1, _ } = subst1_llvm(Subst1, branch_src1(I)),
-      I0 = branch_src1_update(I, NewSrc1),
-      branch_src2_update(I0, NewSrc2);
     #call{} ->
       case call_is_known(I) of
         false ->
@@ -1243,10 +1218,10 @@ subst_defines(Subst, I)->
   case I of
     #alu{} ->
       alu_dst_update(I, subst1(Subst, alu_dst(I)));
+    #alub{dst=[]} ->
+      I;
     #alub{} ->
       alub_dst_update(I, subst1(Subst, alub_dst(I)));
-    #branch{} ->
-      I;
     #call{} ->
       call_dstlist_update(I, subst_list(Subst, call_dstlist(I)));
     #comment{} ->
@@ -1313,7 +1288,6 @@ is_safe(Instr) ->
   case Instr of
     #alu{} -> true;
     #alub{} -> false;
-    #branch{} -> false;
     #call{} -> false;
     #comment{} -> false;
     #enter{} -> false;
@@ -1386,17 +1360,6 @@ redirect_jmp(Jmp, ToOld, ToNew) ->
   %% OBS: In a jmp instruction more than one labels may be identical
   %%      and thus need redirection!
   case Jmp of
-    #branch{} ->
-      TmpJmp = case branch_true_label(Jmp) of
-		 ToOld -> branch_true_label_update(Jmp, ToNew);
-		 _ -> Jmp
-	       end,
-      case branch_false_label(TmpJmp) of
-	ToOld ->
-	  branch_false_label_update(TmpJmp, ToNew);
-	_ ->
-	  TmpJmp
-      end;
     #switch{} ->
       NewLbls = [case Lbl =:= ToOld of
 		   true -> ToNew;
@@ -1591,13 +1554,6 @@ pp_instr(Dev, I) ->
       io:format(Dev, "~n", []);
     #label{} ->
       io:format(Dev, "L~w:~n", [label_name(I)]);
-    #branch{} ->
-      io:format(Dev, "    if (", []),
-      pp_arg(Dev, branch_src1(I)),
-      io:format(Dev, " ~w ", [branch_cond(I)]),
-      pp_arg(Dev, branch_src2(I)),
-      io:format(Dev, ") then L~w (~.2f) else L~w~n", 
-		[branch_true_label(I), branch_pred(I), branch_false_label(I)]);
     #switch{} ->
       io:format(Dev, "    switch (", []),
       pp_arg(Dev, switch_src(I)),
@@ -1606,7 +1562,10 @@ pp_instr(Dev, I) ->
       io:format(Dev, ">\n", []);
     #alub{} ->
       io:format(Dev, "    ", []),
-      pp_arg(Dev, alub_dst(I)),
+      case alub_has_dst(I) of
+	true -> pp_arg(Dev, alub_dst(I));
+	false -> io:format(Dev, "_", [])
+      end,
       io:format(Dev, " <- ", []),
       pp_arg(Dev, alub_src1(I)),
       io:format(Dev, " ~w ", [alub_op(I)]),