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, 23 insertions, 116 deletions

diff --git a/lib/hipe/sparc/hipe_rtl_to_sparc.erl b/lib/hipe/sparc/hipe_rtl_to_sparc.erl
index e170fec3d6..7fab0d95c7 100644
--- a/lib/hipe/sparc/hipe_rtl_to_sparc.erl
+++ b/lib/hipe/sparc/hipe_rtl_to_sparc.erl
@@ -63,7 +63,6 @@ conv_insn(I, Map, Data) ->
   case I of
     #alu{} -> conv_alu(I, Map, Data);
     #alub{} -> conv_alub(I, Map, Data);
-    #branch{} -> conv_branch(I, Map, Data);
     #call{} -> conv_call(I, Map, Data);
     #comment{} -> conv_comment(I, Map, Data);
     #enter{} -> conv_enter(I, Map, Data);
@@ -281,7 +280,12 @@ mk_alu_rs(XAluOp, Src1, Src2, Dst) ->
 
 conv_alub(I, Map, Data) ->
   %% dst = src1 aluop src2; if COND goto label
-  {Dst, Map0} = conv_dst(hipe_rtl:alub_dst(I), Map),
+  HasDst = hipe_rtl:alub_has_dst(I),
+  {Dst, Map0} =
+    case HasDst of
+      false -> {hipe_sparc:mk_g0(), Map};
+      true -> conv_dst(hipe_rtl:alub_dst(I), Map)
+    end,
   {Src1, Map1} = conv_src(hipe_rtl:alub_src1(I), Map0),
   {Src2, Map2} = conv_src(hipe_rtl:alub_src2(I), Map1),
   Cond = conv_cond(hipe_rtl:alub_cond(I)),
@@ -307,67 +311,33 @@ conv_alub(I, Map, Data) ->
 	I1 ++
 	[hipe_sparc:mk_rdy(TmpHi),
 	 hipe_sparc:mk_alu('sra', Dst, hipe_sparc:mk_uimm5(31), TmpSign) |
-	 conv_alub2(G0, TmpSign, 'sub', NewCond, TmpHi, I)];
+	 conv_alub2(G0, TmpSign, 'cmpcc', NewCond, TmpHi, I)];
       _ ->
-	conv_alub2(Dst, Src1, RtlAlubOp, Cond, Src2, I)
+	XAluOp =
+	  case (not HasDst) andalso RtlAlubOp =:= 'sub' of
+	    true -> 'cmpcc'; % == a subcc that commutes
+	    false -> conv_alubop_cc(RtlAlubOp)
+	  end,
+	conv_alub2(Dst, Src1, XAluOp, Cond, Src2, I)
     end,
   {I2, Map2, Data}.
 
--ifdef(notdef).	% XXX: only for sparc64, alas
-conv_alub2(Dst, Src1, RtlAlubOp, Cond, Src2, I) ->
-  case conv_cond_rcond(Cond) of
-    [] ->
-      conv_alub_bp(Dst, Src1, RtlAlubOp, Cond, Src2, I);
-    RCond ->
-      conv_alub_br(Dst, Src1, RtlAlubOp, RCond, Src2, I)
-  end.
+conv_alub2(Dst, Src1, XAluOp, Cond, Src2, I) ->
+  conv_alub_bp(Dst, Src1, XAluOp, Cond, Src2, I).
 
-conv_alub_br(Dst, Src1, RtlAlubOp, RCond, Src2, I) ->
-  TrueLab = hipe_rtl:alub_true_label(I),
-  FalseLab = hipe_rtl:alub_false_label(I),
-  Pred = hipe_rtl:alub_pred(I),
-  %% "Dst = Src1 AluOp Src2; if COND" becomes
-  %% "Dst = Src1 AluOp Src2; if-COND(Dst)"
-  {I2, _DidCommute} = mk_alu(conv_alubop_nocc(RtlAlubOp), Src1, Src2, Dst),
-  I2 ++ mk_pseudo_br(RCond, Dst, TrueLab, FalseLab, Pred).
-
-conv_cond_rcond(Cond) ->
-  case Cond of
-    'e'  -> 'z';
-    'ne' -> 'nz';
-    'g'  -> 'gz';
-    'ge' -> 'gez';
-    'l'  -> 'lz';
-    'le' -> 'lez';
-    _	 -> []	% vs, vc, gu, geu, lu, leu
-  end.
-
-conv_alubop_nocc(RtlAlubOp) ->
-  case RtlAlubOp of
-    'add' -> 'add';
-    'sub' -> 'sub';
-    %% mul: handled elsewhere
-    'or' -> 'or';
-    'and' -> 'and';
-    'xor' -> 'xor'
-    %% no shift ops
-  end.
-
-mk_pseudo_br(RCond, Dst, TrueLab, FalseLab, Pred) ->
-  [hipe_sparc:mk_pseudo_br(RCond, Dst, TrueLab, FalseLab, Pred)].
--else.
-conv_alub2(Dst, Src1, RtlAlubOp, Cond, Src2, I) ->
-  conv_alub_bp(Dst, Src1, RtlAlubOp, Cond, Src2, I).
--endif.
-
-conv_alub_bp(Dst, Src1, RtlAlubOp, Cond, Src2, I) ->
+conv_alub_bp(Dst, Src1, XAluOp, Cond, Src2, I) ->
   TrueLab = hipe_rtl:alub_true_label(I),
   FalseLab = hipe_rtl:alub_false_label(I),
   Pred = hipe_rtl:alub_pred(I),
   %% "Dst = Src1 AluOp Src2; if COND" becomes
   %% "Dst = Src1 AluOpCC Src22; if-COND(CC)"
-  {I2, _DidCommute} = mk_alu(conv_alubop_cc(RtlAlubOp), Src1, Src2, Dst),
-  I2 ++ mk_pseudo_bp(Cond, TrueLab, FalseLab, Pred).
+  {I2, DidCommute} = mk_alu(XAluOp, Src1, Src2, Dst),
+  NewCond =
+    case DidCommute andalso XAluOp =:= 'cmpcc' of
+      true -> commute_cond(Cond); % subcc does not commute; its conditions do
+      false -> Cond
+    end,
+  I2 ++ mk_pseudo_bp(NewCond, TrueLab, FalseLab, Pred).
 
 conv_alubop_cc(RtlAlubOp) ->
   case RtlAlubOp of
@@ -380,69 +350,6 @@ conv_alubop_cc(RtlAlubOp) ->
     %% no shift ops
   end.
 
-conv_branch(I, Map, Data) ->
-  %% <unused> = src1 - src2; if COND goto label
-  {Src1, Map0} = conv_src(hipe_rtl:branch_src1(I), Map),
-  {Src2, Map1} = conv_src(hipe_rtl:branch_src2(I), Map0),
-  Cond = conv_cond(hipe_rtl:branch_cond(I)),
-  I2 = conv_branch2(Src1, Cond, Src2, I),
-  {I2, Map1, Data}.
-
--ifdef(notdef).	% XXX: only for sparc64, alas
-conv_branch2(Src1, Cond, Src2, I) ->
-  case conv_cond_rcond(Cond) of
-    [] ->
-      conv_branch_bp(Src1, Cond, Src2, I);
-    RCond ->
-      conv_branch_br(Src1, RCond, Src2, I)
-  end.
-
-conv_branch_br(Src1, RCond, Src2, I) ->
-  TrueLab = hipe_rtl:branch_true_label(I),
-  FalseLab = hipe_rtl:branch_false_label(I),
-  Pred = hipe_rtl:branch_pred(I),
-  %% "if src1-COND-src2" becomes
-  %% "sub src1,src2,tmp; if-COND(tmp)"
-  Dst = hipe_sparc:mk_new_temp('untagged'),
-  XAluOp = 'cmp',	% == a sub that commutes
-  {I1, DidCommute} = mk_alu(XAluOp, Src1, Src2, Dst),
-  NewRCond =
-    case DidCommute of
-      true -> commute_rcond(RCond);
-      false -> RCond
-    end,
-  I1 ++ mk_pseudo_br(NewRCond, Dst, TrueLab, FalseLab, Pred).
-
-commute_rcond(RCond) ->	% if x RCond y, then y commute_rcond(RCond) x
-  case RCond of
-    'z'   -> 'z';	% ==, ==
-    'nz'  -> 'nz';	% !=, !=
-    'gz'  -> 'lz';	% >, <
-    'gez' -> 'lez';	% >=, <=
-    'lz'  -> 'gz';	% <, >
-    'lez' -> 'gez'	% <=, >=
-  end.
--else.
-conv_branch2(Src1, Cond, Src2, I) ->
-  conv_branch_bp(Src1, Cond, Src2, I).
--endif.
-
-conv_branch_bp(Src1, Cond, Src2, I) ->
-  TrueLab = hipe_rtl:branch_true_label(I),
-  FalseLab = hipe_rtl:branch_false_label(I),
-  Pred = hipe_rtl:branch_pred(I),
-  %% "if src1-COND-src2" becomes
-  %% "subcc src1,src2,%g0; if-COND(CC)"
-  Dst = hipe_sparc:mk_g0(),
-  XAluOp = 'cmpcc',	% == a subcc that commutes
-  {I1, DidCommute} = mk_alu(XAluOp, Src1, Src2, Dst),
-  NewCond =
-    case DidCommute of
-      true -> commute_cond(Cond);
-      false -> Cond
-    end,
-  I1 ++ mk_pseudo_bp(NewCond, TrueLab, FalseLab, Pred).
-
 conv_call(I, Map, Data) ->
   {Args, Map0} = conv_src_list(hipe_rtl:call_arglist(I), Map),
   {Dsts, Map1} = conv_dst_list(hipe_rtl:call_dstlist(I), Map0),