hipe: Add hipe_regalloc_prepass

hipe_regalloc_prepass speeds up register allocation by spilling any temp
that is live over a call (which clobbers all register).

In order to detect these, a new function was added to the target
interface; defines_all_alloc/1, that takes an instruction and returns a
boolean.

2 files changed, 13 insertions, 1 deletions

diff --git a/lib/hipe/x86/hipe_x86_defuse.erl b/lib/hipe/x86/hipe_x86_defuse.erl
index 9cba6cbe4b..4455def74e 100644
--- a/lib/hipe/x86/hipe_x86_defuse.erl
+++ b/lib/hipe/x86/hipe_x86_defuse.erl
@@ -35,7 +35,7 @@
 -endif.
 
 -module(?HIPE_X86_DEFUSE).
--export([insn_def/1, insn_use/1]). %% src_use/1]).
+-export([insn_def/1, insn_defs_all/1, insn_use/1]). %% src_use/1]).
 -include("../x86/hipe_x86.hrl").
 
 %%%
@@ -64,6 +64,16 @@ insn_def(I) ->
     _ -> []
   end.
 
+
+%% @doc Answers whether instruction I defines all allocatable registers. Used by
+%% hipe_regalloc_prepass.
+-spec insn_defs_all(_) -> boolean().
+insn_defs_all(I) ->
+  case I of
+    #pseudo_call{} -> true;
+    _ -> false
+  end.
+
 dst_def(Dst) ->
   case Dst of
     #x86_temp{} -> [Dst];
diff --git a/lib/hipe/x86/hipe_x86_registers.erl b/lib/hipe/x86/hipe_x86_registers.erl
index 179d734501..f00bbfb280 100644
--- a/lib/hipe/x86/hipe_x86_registers.erl
+++ b/lib/hipe/x86/hipe_x86_registers.erl
@@ -224,6 +224,8 @@ ret(N) ->
 	    exit({?MODULE, ret, N})
     end.
 
+%% Note: the fact that (allocatable() UNION allocatable_x87()) is a subset of
+%% call_clobbered() is hard-coded in hipe_x86_defuse:insn_defs_all/1
 call_clobbered() ->
     [{?EAX,tagged},{?EAX,untagged},	% does the RA strip the type or not?
      {?EDX,tagged},{?EDX,untagged},