From 1567585dda8bc604871be06a37aa5d19ad6d28f3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20L=C3=A5ng?= <margnus1@telia.com>
Date: Sat, 4 Jun 2016 20:10:02 +0200
Subject: hipe_x86: Use lea instead of move+add

This is primarily useful for heap allocations, as a two-address 'add'
can't be used to both copy the heap pointer to another register, and add
the tag.
---
 lib/hipe/x86/hipe_rtl_to_x86.erl            | 18 +++++++++++++++++-
 lib/hipe/x86/hipe_x86_ra_postconditions.erl | 24 ++++++++++++++++--------
 2 files changed, 33 insertions(+), 9 deletions(-)

(limited to 'lib/hipe/x86')

diff --git a/lib/hipe/x86/hipe_rtl_to_x86.erl b/lib/hipe/x86/hipe_rtl_to_x86.erl
index 79028b0652..4c8c98551c 100644
--- a/lib/hipe/x86/hipe_rtl_to_x86.erl
+++ b/lib/hipe/x86/hipe_rtl_to_x86.erl
@@ -85,7 +85,7 @@ conv_insn(I, Map, Data) ->
 	  true ->
 	    conv_shift(Dst, Src1, BinOp, Src2);
 	  false ->
-	    conv_alu(Dst, Src1, BinOp, Src2, [])
+	    conv_alu_nocc(Dst, Src1, BinOp, Src2, [])
 	end,
       {FixSrc1++FixSrc2++I2, Map2, Data};
     #alub{} ->
@@ -250,6 +250,22 @@ conv_insn(I, Map, Data) ->
 %%% Finalise the conversion of a 3-address ALU operation, taking
 %%% care to not introduce more temps and moves than necessary.
 
+conv_alu_nocc(Dst, Src1, 'add', Src2, Tail) ->
+  case (not same_opnd(Dst, Src1)) andalso (not same_opnd(Dst, Src2))
+    andalso (hipe_x86:is_temp(Src1) orelse hipe_x86:is_temp(Src2))
+  of
+    false -> conv_alu(Dst, Src1, 'add', Src2, Tail);
+    true -> % Use LEA
+      Type = typeof_dst(Dst),
+      Mem = case hipe_x86:is_temp(Src1) of
+	      true  -> hipe_x86:mk_mem(Src1, Src2, Type);
+	      false -> hipe_x86:mk_mem(Src2, Src1, Type)
+	    end,
+      [hipe_x86:mk_lea(Mem, Dst) | Tail]
+  end;
+conv_alu_nocc(Dst, Src1, BinOp, Src2, Tail) ->
+  conv_alu(Dst, Src1, BinOp, Src2, Tail).
+
 conv_alu(Dst, Src1, 'imul', Src2, Tail) ->
   mk_imul(Src1, Src2, Dst, Tail);
 conv_alu(Dst, Src1, BinOp, Src2, Tail) ->
diff --git a/lib/hipe/x86/hipe_x86_ra_postconditions.erl b/lib/hipe/x86/hipe_x86_ra_postconditions.erl
index 343d04977d..c73d029b9b 100644
--- a/lib/hipe/x86/hipe_x86_ra_postconditions.erl
+++ b/lib/hipe/x86/hipe_x86_ra_postconditions.erl
@@ -173,14 +173,22 @@ do_jmp_switch(I, TempMap, Strategy) ->
 %%% Fix a lea op.
 
 do_lea(I, TempMap, Strategy) ->
-  #lea{temp=Temp} = I,
-  case is_spilled(Temp, TempMap) of
-    false ->
-      {[I], false};
-    true ->
-      NewTmp = spill_temp('untagged', Strategy),
-      {[I#lea{temp=NewTmp}, hipe_x86:mk_move(NewTmp, Temp)],
-       true}
+  #lea{mem=Mem0,temp=Temp0} = I,
+  {FixMem, Mem, DidSpill1} = fix_mem_operand(Mem0, TempMap, temp1(Strategy)),
+  case Mem of
+    #x86_mem{base=Base, off=#x86_imm{value=0}} ->
+      %% We've decayed into a move due to both operands being memory (there's an
+      %% 'add' in FixMem).
+      {FixMem ++ [hipe_x86:mk_move(Base, Temp0)], DidSpill1};
+    #x86_mem{} ->
+      {StoreTemp, Temp, DidSpill2} =
+	case is_mem_opnd(Temp0, TempMap) of
+	  false -> {[], Temp0, false};
+	  true ->
+	    Temp1 = clone2(Temp0, temp0(Strategy)),
+	    {[hipe_x86:mk_move(Temp1, Temp0)], Temp1, true}
+	end,
+      {FixMem ++ [I#lea{mem=Mem,temp=Temp} | StoreTemp], DidSpill1 or DidSpill2}
   end.
 
 %%% Fix a move op.
-- 
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