hipe: Add pseudo_spill_f?move instructions

These pseudo instructions are added to all backends and allow spill slot
to spill slot move coalescing in a clean way.

They have regular move semantics, but contain an additional scratch
register to be used if both source and destination are spilled, and can
not be move coalesced.

Additionally, a register allocator callback
Target:is_spill_move(Instr, Context) is added which allows the spill
slot allocators to check for these instructions and try to coalesce the
spill slots the two temporaries are allocated to.

1 files changed, 20 insertions, 5 deletions

diff --git a/lib/hipe/arm/hipe_arm_ra_finalise.erl b/lib/hipe/arm/hipe_arm_ra_finalise.erl
index 9bfe0a9a83..80cd470708 100644
--- a/lib/hipe/arm/hipe_arm_ra_finalise.erl
+++ b/lib/hipe/arm/hipe_arm_ra_finalise.erl
@@ -25,11 +25,17 @@ ra_bb(BB, Map) ->
   hipe_bb:code_update(BB, ra_code(hipe_bb:code(BB), Map, [])).
 
 ra_code([I|Insns], Map, Accum) ->
-  ra_code(Insns, Map, [ra_insn(I, Map) | Accum]);
+  ra_code(Insns, Map, ra_insn(I, Map, Accum));
 ra_code([], _Map, Accum) ->
   lists:reverse(Accum).
 
-ra_insn(I, Map) ->
+ra_insn(I, Map, Accum) ->
+  case I of
+    #pseudo_move{} -> ra_pseudo_move(I, Map, Accum);
+    _ -> [ra_insn_1(I, Map) | Accum]
+  end.
+
+ra_insn_1(I, Map) ->
   case I of
     #alu{} -> ra_alu(I, Map);
     #cmp{} -> ra_cmp(I, Map);
@@ -38,7 +44,7 @@ ra_insn(I, Map) ->
     #move{} -> ra_move(I, Map);
     #pseudo_call{} -> ra_pseudo_call(I, Map);
     #pseudo_li{} -> ra_pseudo_li(I, Map);
-    #pseudo_move{} -> ra_pseudo_move(I, Map);
+    #pseudo_spill_move{} -> ra_pseudo_spill_move(I, Map);
     #pseudo_switch{} -> ra_pseudo_switch(I, Map);
     #pseudo_tailcall{} -> ra_pseudo_tailcall(I, Map);
     #smull{} -> ra_smull(I, Map);
@@ -80,10 +86,19 @@ ra_pseudo_li(I=#pseudo_li{dst=Dst}, Map) ->
   NewDst = ra_temp(Dst, Map),
   I#pseudo_li{dst=NewDst}.
 
-ra_pseudo_move(I=#pseudo_move{dst=Dst,src=Src}, Map) ->
+ra_pseudo_move(I=#pseudo_move{dst=Dst,src=Src}, Map, Accum) ->
+  NewDst = ra_temp(Dst, Map),
+  NewSrc = ra_temp(Src, Map),
+  case NewSrc#arm_temp.reg =:= NewDst#arm_temp.reg of
+    true -> Accum;
+    false -> [I#pseudo_move{dst=NewDst,src=NewSrc} | Accum]
+  end.
+
+ra_pseudo_spill_move(I=#pseudo_spill_move{dst=Dst,temp=Temp,src=Src}, Map) ->
   NewDst = ra_temp(Dst, Map),
+  NewTemp = ra_temp(Temp, Map),
   NewSrc = ra_temp(Src, Map),
-  I#pseudo_move{dst=NewDst,src=NewSrc}.
+  I#pseudo_spill_move{dst=NewDst, temp=NewTemp, src=NewSrc}.
 
 ra_pseudo_switch(I=#pseudo_switch{jtab=JTab,index=Index}, Map) ->
   NewJTab = ra_temp(JTab, Map),