diff --git a/.depend b/.depend
index 7fff8d312..112100725 100644
--- a/.depend
+++ b/.depend
@@ -10,6 +10,8 @@ utils/misc.cmo: utils/misc.cmi
 utils/misc.cmx: utils/misc.cmi 
 utils/nativeint.cmo: utils/nativeint.cmi 
 utils/nativeint.cmx: utils/nativeint.cmi 
+utils/safearith.cmo: utils/safearith.cmi 
+utils/safearith.cmx: utils/safearith.cmi 
 utils/tbl.cmo: utils/tbl.cmi 
 utils/tbl.cmx: utils/tbl.cmi 
 utils/terminfo.cmo: utils/terminfo.cmi 
@@ -368,6 +370,7 @@ asmcomp/closure.cmi: asmcomp/clambda.cmi bytecomp/lambda.cmi
 asmcomp/cmm.cmi: typing/ident.cmi utils/nativeint.cmi 
 asmcomp/cmmgen.cmi: asmcomp/clambda.cmi asmcomp/cmm.cmi 
 asmcomp/codegen.cmi: asmcomp/cmm.cmi 
+asmcomp/comballoc.cmi: asmcomp/mach.cmi 
 asmcomp/compilenv.cmi: asmcomp/clambda.cmi typing/ident.cmi 
 asmcomp/emit.cmi: asmcomp/cmm.cmi asmcomp/linearize.cmi 
 asmcomp/emitaux.cmi: utils/nativeint.cmi 
@@ -390,24 +393,24 @@ asmcomp/selectgen.cmi: asmcomp/arch.cmo asmcomp/cmm.cmi typing/ident.cmi \
 asmcomp/selection.cmi: asmcomp/cmm.cmi asmcomp/mach.cmi 
 asmcomp/spill.cmi: asmcomp/mach.cmi 
 asmcomp/split.cmi: asmcomp/mach.cmi 
-asmcomp/arch.cmo: utils/config.cmi 
-asmcomp/arch.cmx: utils/config.cmx 
+asmcomp/arch.cmo: utils/nativeint.cmi 
+asmcomp/arch.cmx: utils/nativeint.cmx 
 asmcomp/asmgen.cmo: utils/clflags.cmo asmcomp/closure.cmi asmcomp/cmm.cmi \
-    asmcomp/cmmgen.cmi asmcomp/coloring.cmi utils/config.cmi asmcomp/emit.cmi \
-    asmcomp/emitaux.cmi asmcomp/interf.cmi asmcomp/linearize.cmi \
-    asmcomp/liveness.cmi asmcomp/mach.cmi utils/misc.cmi asmcomp/printcmm.cmi \
-    asmcomp/printlinear.cmi asmcomp/printmach.cmi asmcomp/proc.cmi \
-    asmcomp/reg.cmi asmcomp/reload.cmi asmcomp/scheduling.cmi \
-    asmcomp/selection.cmi asmcomp/spill.cmi asmcomp/split.cmi \
-    asmcomp/asmgen.cmi 
+    asmcomp/cmmgen.cmi asmcomp/coloring.cmi asmcomp/comballoc.cmi \
+    utils/config.cmi asmcomp/emit.cmi asmcomp/emitaux.cmi asmcomp/interf.cmi \
+    asmcomp/linearize.cmi asmcomp/liveness.cmi asmcomp/mach.cmi \
+    utils/misc.cmi asmcomp/printcmm.cmi asmcomp/printlinear.cmi \
+    asmcomp/printmach.cmi asmcomp/proc.cmi asmcomp/reg.cmi asmcomp/reload.cmi \
+    asmcomp/scheduling.cmi asmcomp/selection.cmi asmcomp/spill.cmi \
+    asmcomp/split.cmi asmcomp/asmgen.cmi 
 asmcomp/asmgen.cmx: utils/clflags.cmx asmcomp/closure.cmx asmcomp/cmm.cmx \
-    asmcomp/cmmgen.cmx asmcomp/coloring.cmx utils/config.cmx asmcomp/emit.cmx \
-    asmcomp/emitaux.cmx asmcomp/interf.cmx asmcomp/linearize.cmx \
-    asmcomp/liveness.cmx asmcomp/mach.cmx utils/misc.cmx asmcomp/printcmm.cmx \
-    asmcomp/printlinear.cmx asmcomp/printmach.cmx asmcomp/proc.cmx \
-    asmcomp/reg.cmx asmcomp/reload.cmx asmcomp/scheduling.cmx \
-    asmcomp/selection.cmx asmcomp/spill.cmx asmcomp/split.cmx \
-    asmcomp/asmgen.cmi 
+    asmcomp/cmmgen.cmx asmcomp/coloring.cmx asmcomp/comballoc.cmx \
+    utils/config.cmx asmcomp/emit.cmx asmcomp/emitaux.cmx asmcomp/interf.cmx \
+    asmcomp/linearize.cmx asmcomp/liveness.cmx asmcomp/mach.cmx \
+    utils/misc.cmx asmcomp/printcmm.cmx asmcomp/printlinear.cmx \
+    asmcomp/printmach.cmx asmcomp/proc.cmx asmcomp/reg.cmx asmcomp/reload.cmx \
+    asmcomp/scheduling.cmx asmcomp/selection.cmx asmcomp/spill.cmx \
+    asmcomp/split.cmx asmcomp/asmgen.cmi 
 asmcomp/asmlibrarian.cmo: utils/ccomp.cmi asmcomp/clambda.cmi \
     utils/clflags.cmo asmcomp/compilenv.cmi utils/config.cmi utils/misc.cmi \
     asmcomp/asmlibrarian.cmi 
@@ -458,17 +461,19 @@ asmcomp/codegen.cmx: asmcomp/cmm.cmx asmcomp/coloring.cmx asmcomp/emit.cmx \
     asmcomp/codegen.cmi 
 asmcomp/coloring.cmo: asmcomp/proc.cmi asmcomp/reg.cmi asmcomp/coloring.cmi 
 asmcomp/coloring.cmx: asmcomp/proc.cmx asmcomp/reg.cmx asmcomp/coloring.cmi 
+asmcomp/comballoc.cmo: utils/config.cmi asmcomp/reg.cmi asmcomp/comballoc.cmi 
+asmcomp/comballoc.cmx: utils/config.cmx asmcomp/reg.cmx asmcomp/comballoc.cmi 
 asmcomp/compilenv.cmo: asmcomp/clambda.cmi utils/config.cmi typing/env.cmi \
     typing/ident.cmi utils/misc.cmi asmcomp/compilenv.cmi 
 asmcomp/compilenv.cmx: asmcomp/clambda.cmx utils/config.cmx typing/env.cmx \
     typing/ident.cmx utils/misc.cmx asmcomp/compilenv.cmi 
-asmcomp/emit.cmo: asmcomp/arch.cmo asmcomp/cmm.cmi asmcomp/compilenv.cmi \
-    utils/config.cmi asmcomp/emitaux.cmi asmcomp/linearize.cmi \
-    parsing/location.cmi asmcomp/mach.cmi utils/misc.cmi utils/nativeint.cmi \
+asmcomp/emit.cmo: asmcomp/arch.cmo utils/clflags.cmo asmcomp/cmm.cmi \
+    asmcomp/compilenv.cmi utils/config.cmi asmcomp/emitaux.cmi \
+    asmcomp/linearize.cmi asmcomp/mach.cmi utils/misc.cmi utils/nativeint.cmi \
     asmcomp/proc.cmi asmcomp/reg.cmi asmcomp/emit.cmi 
-asmcomp/emit.cmx: asmcomp/arch.cmx asmcomp/cmm.cmx asmcomp/compilenv.cmx \
-    utils/config.cmx asmcomp/emitaux.cmx asmcomp/linearize.cmx \
-    parsing/location.cmx asmcomp/mach.cmx utils/misc.cmx utils/nativeint.cmx \
+asmcomp/emit.cmx: asmcomp/arch.cmx utils/clflags.cmx asmcomp/cmm.cmx \
+    asmcomp/compilenv.cmx utils/config.cmx asmcomp/emitaux.cmx \
+    asmcomp/linearize.cmx asmcomp/mach.cmx utils/misc.cmx utils/nativeint.cmx \
     asmcomp/proc.cmx asmcomp/reg.cmx asmcomp/emit.cmi 
 asmcomp/emitaux.cmo: utils/nativeint.cmi asmcomp/emitaux.cmi 
 asmcomp/emitaux.cmx: utils/nativeint.cmx asmcomp/emitaux.cmi 
@@ -502,16 +507,16 @@ asmcomp/printmach.cmo: asmcomp/arch.cmo asmcomp/cmm.cmi asmcomp/mach.cmi \
 asmcomp/printmach.cmx: asmcomp/arch.cmx asmcomp/cmm.cmx asmcomp/mach.cmx \
     utils/nativeint.cmx asmcomp/printcmm.cmx asmcomp/proc.cmx asmcomp/reg.cmx \
     asmcomp/printmach.cmi 
-asmcomp/proc.cmo: asmcomp/arch.cmo utils/ccomp.cmi utils/clflags.cmo \
-    asmcomp/cmm.cmi asmcomp/mach.cmi utils/misc.cmi asmcomp/reg.cmi \
-    asmcomp/proc.cmi 
-asmcomp/proc.cmx: asmcomp/arch.cmx utils/ccomp.cmx utils/clflags.cmx \
-    asmcomp/cmm.cmx asmcomp/mach.cmx utils/misc.cmx asmcomp/reg.cmx \
-    asmcomp/proc.cmi 
+asmcomp/proc.cmo: asmcomp/arch.cmo utils/ccomp.cmi asmcomp/cmm.cmi \
+    asmcomp/mach.cmi utils/misc.cmi asmcomp/reg.cmi asmcomp/proc.cmi 
+asmcomp/proc.cmx: asmcomp/arch.cmx utils/ccomp.cmx asmcomp/cmm.cmx \
+    asmcomp/mach.cmx utils/misc.cmx asmcomp/reg.cmx asmcomp/proc.cmi 
 asmcomp/reg.cmo: asmcomp/cmm.cmi asmcomp/reg.cmi 
 asmcomp/reg.cmx: asmcomp/cmm.cmx asmcomp/reg.cmi 
-asmcomp/reload.cmo: asmcomp/reloadgen.cmi asmcomp/reload.cmi 
-asmcomp/reload.cmx: asmcomp/reloadgen.cmx asmcomp/reload.cmi 
+asmcomp/reload.cmo: asmcomp/arch.cmo asmcomp/cmm.cmi asmcomp/mach.cmi \
+    asmcomp/reg.cmi asmcomp/reloadgen.cmi asmcomp/reload.cmi 
+asmcomp/reload.cmx: asmcomp/arch.cmx asmcomp/cmm.cmx asmcomp/mach.cmx \
+    asmcomp/reg.cmx asmcomp/reloadgen.cmx asmcomp/reload.cmi 
 asmcomp/reloadgen.cmo: asmcomp/mach.cmi utils/misc.cmi asmcomp/reg.cmi \
     asmcomp/reloadgen.cmi 
 asmcomp/reloadgen.cmx: asmcomp/mach.cmx utils/misc.cmx asmcomp/reg.cmx \
@@ -520,10 +525,8 @@ asmcomp/schedgen.cmo: asmcomp/arch.cmo asmcomp/cmm.cmi asmcomp/linearize.cmi \
     asmcomp/mach.cmi utils/misc.cmi asmcomp/reg.cmi asmcomp/schedgen.cmi 
 asmcomp/schedgen.cmx: asmcomp/arch.cmx asmcomp/cmm.cmx asmcomp/linearize.cmx \
     asmcomp/mach.cmx utils/misc.cmx asmcomp/reg.cmx asmcomp/schedgen.cmi 
-asmcomp/scheduling.cmo: asmcomp/arch.cmo asmcomp/mach.cmi \
-    asmcomp/schedgen.cmi asmcomp/scheduling.cmi 
-asmcomp/scheduling.cmx: asmcomp/arch.cmx asmcomp/mach.cmx \
-    asmcomp/schedgen.cmx asmcomp/scheduling.cmi 
+asmcomp/scheduling.cmo: asmcomp/schedgen.cmi asmcomp/scheduling.cmi 
+asmcomp/scheduling.cmx: asmcomp/schedgen.cmx asmcomp/scheduling.cmi 
 asmcomp/selectgen.cmo: asmcomp/arch.cmo asmcomp/cmm.cmi typing/ident.cmi \
     asmcomp/mach.cmi utils/misc.cmi utils/nativeint.cmi asmcomp/proc.cmi \
     asmcomp/reg.cmi utils/tbl.cmi asmcomp/selectgen.cmi 
@@ -531,11 +534,11 @@ asmcomp/selectgen.cmx: asmcomp/arch.cmx asmcomp/cmm.cmx typing/ident.cmx \
     asmcomp/mach.cmx utils/misc.cmx utils/nativeint.cmx asmcomp/proc.cmx \
     asmcomp/reg.cmx utils/tbl.cmx asmcomp/selectgen.cmi 
 asmcomp/selection.cmo: asmcomp/arch.cmo asmcomp/cmm.cmi asmcomp/mach.cmi \
-    utils/misc.cmi asmcomp/reg.cmi asmcomp/selectgen.cmi \
-    asmcomp/selection.cmi 
+    utils/misc.cmi utils/nativeint.cmi asmcomp/proc.cmi asmcomp/reg.cmi \
+    asmcomp/selectgen.cmi asmcomp/selection.cmi 
 asmcomp/selection.cmx: asmcomp/arch.cmx asmcomp/cmm.cmx asmcomp/mach.cmx \
-    utils/misc.cmx asmcomp/reg.cmx asmcomp/selectgen.cmx \
-    asmcomp/selection.cmi 
+    utils/misc.cmx utils/nativeint.cmx asmcomp/proc.cmx asmcomp/reg.cmx \
+    asmcomp/selectgen.cmx asmcomp/selection.cmi 
 asmcomp/spill.cmo: asmcomp/mach.cmi asmcomp/proc.cmi asmcomp/reg.cmi \
     asmcomp/spill.cmi 
 asmcomp/spill.cmx: asmcomp/mach.cmx asmcomp/proc.cmx asmcomp/reg.cmx \
diff --git a/Makefile b/Makefile
index dc955c9d4..c160f5f72 100644
--- a/Makefile
+++ b/Makefile
@@ -54,7 +54,8 @@ ASMCOMP=asmcomp/arch.cmo asmcomp/cmm.cmo asmcomp/printcmm.cmo \
   asmcomp/clambda.cmo asmcomp/compilenv.cmo \
   asmcomp/closure.cmo asmcomp/cmmgen.cmo \
   asmcomp/printmach.cmo asmcomp/selectgen.cmo asmcomp/selection.cmo \
-  asmcomp/liveness.cmo asmcomp/spill.cmo asmcomp/split.cmo \
+  asmcomp/comballoc.cmo asmcomp/liveness.cmo \
+  asmcomp/spill.cmo asmcomp/split.cmo \
   asmcomp/interf.cmo asmcomp/coloring.cmo \
   asmcomp/reloadgen.cmo asmcomp/reload.cmo \
   asmcomp/printlinear.cmo asmcomp/linearize.cmo \
diff --git a/Makefile.nt b/Makefile.nt
index 461ac1d1f..594c690e1 100644
--- a/Makefile.nt
+++ b/Makefile.nt
@@ -52,7 +52,8 @@ ASMCOMP=asmcomp\arch.cmo asmcomp\cmm.cmo asmcomp\printcmm.cmo \
   asmcomp\clambda.cmo asmcomp\compilenv.cmo \
   asmcomp\closure.cmo asmcomp\cmmgen.cmo \
   asmcomp\printmach.cmo asmcomp\selectgen.cmo asmcomp\selection.cmo \
-  asmcomp\liveness.cmo asmcomp\spill.cmo asmcomp\split.cmo \
+  amscomp\comballoc.cmo asmcomp\liveness.cmo \
+  asmcomp\spill.cmo asmcomp\split.cmo \
   asmcomp\interf.cmo asmcomp\coloring.cmo \
   asmcomp\reloadgen.cmo asmcomp\reload.cmo \
   asmcomp\printlinear.cmo asmcomp\linearize.cmo \
diff --git a/asmcomp/asmgen.ml b/asmcomp/asmgen.ml
index 358f8528e..460408ab6 100644
--- a/asmcomp/asmgen.ml
+++ b/asmcomp/asmgen.ml
@@ -62,6 +62,8 @@ let compile_fundecl fd_cmm =
   fd_cmm
   ++ Selection.fundecl
   ++ pass_dump_if dump_selection "After instruction selection"
+  ++ Comballoc.fundecl
+  ++ pass_dump_if dump_combine "After allocation combining"
   ++ liveness
   ++ pass_dump_if dump_live "Liveness analysis"
   ++ Spill.fundecl
diff --git a/asmcomp/comballoc.ml b/asmcomp/comballoc.ml
new file mode 100644
index 000000000..1eb361df2
--- /dev/null
+++ b/asmcomp/comballoc.ml
@@ -0,0 +1,88 @@
+(***********************************************************************)
+(*                                                                     *)
+(*                           Objective Caml                            *)
+(*                                                                     *)
+(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
+(*                                                                     *)
+(*  Copyright 1999 Institut National de Recherche en Informatique et   *)
+(*  en Automatique.  Distributed only by permission.                   *)
+(*                                                                     *)
+(***********************************************************************)
+
+(* $Id$ *)
+
+(* Combine heap allocations occurring in the same basic block *)
+
+open Mach
+
+type allocation_state =
+    No_alloc                            (* no allocation is pending *)
+  | Pending_alloc of Reg.t * int        (* an allocation is pending *)
+(* The arguments of Pending_alloc(reg, ofs) are:
+     reg  the register holding the result of the last allocation
+     ofs  the alloc position in the allocated block *)
+
+let allocated_size = function
+    No_alloc -> 0
+  | Pending_alloc(reg, ofs) -> ofs
+
+let rec combine i allocstate =
+  match i.desc with
+    Iend | Ireturn | Iexit | Iraise ->
+      (i, allocated_size allocstate)
+  | Iop(Ialloc sz) ->
+      begin match allocstate with
+        No_alloc ->
+          let (newnext, newsz) =
+            combine i.next (Pending_alloc(i.res.(0), sz)) in
+          (instr_cons (Iop(Ialloc newsz)) i.arg i.res newnext, 0)
+      | Pending_alloc(reg, ofs) ->
+          if ofs + sz < Config.max_young_wosize then begin
+            let (newnext, newsz) =
+              combine i.next (Pending_alloc(reg, ofs + sz)) in
+            (instr_cons (Iop(Iintop_imm(Iadd, ofs))) [| reg |] i.res newnext,
+             newsz)
+          end else begin
+            let (newnext, newsz) =
+              combine i.next (Pending_alloc(i.res.(0), sz)) in
+            (instr_cons (Iop(Ialloc newsz)) i.arg i.res newnext, ofs)
+          end
+      end
+  | Iop(Icall_ind | Icall_imm _ | Iextcall(_, _) |
+        Itailcall_ind | Itailcall_imm _) ->
+      let newnext = combine_restart i.next in
+      (instr_cons i.desc i.arg i.res newnext, allocated_size allocstate)
+  | Iop op ->
+      let (newnext, sz) = combine i.next allocstate in
+      (instr_cons i.desc i.arg i.res newnext, sz)
+  | Iifthenelse(test, ifso, ifnot) ->
+      let newifso = combine_restart ifso in
+      let newifnot = combine_restart ifnot in
+      let newnext = combine_restart i.next in
+      (instr_cons (Iifthenelse(test, newifso, newifnot)) i.arg i.res newnext,
+       allocated_size allocstate)
+  | Iswitch(table, cases) ->
+      let newcases = Array.map combine_restart cases in
+      let newnext = combine_restart i.next in
+      (instr_cons (Iswitch(table, newcases)) i.arg i.res newnext,
+       allocated_size allocstate)
+  | Iloop(body) ->
+      let newbody = combine_restart body in
+      (instr_cons (Iloop(newbody)) i.arg i.res i.next,
+       allocated_size allocstate)
+  | Icatch(body, handler) ->
+      let (newbody, sz) = combine body allocstate in
+      let newhandler = combine_restart handler in
+      let newnext = combine_restart i.next in
+      (instr_cons (Icatch(newbody, newhandler)) i.arg i.res newnext, sz)
+  | Itrywith(body, handler) ->
+      let (newbody, sz) = combine body allocstate in
+      let newhandler = combine_restart handler in
+      let newnext = combine_restart i.next in
+      (instr_cons (Itrywith(newbody, newhandler)) i.arg i.res newnext, sz)
+
+and combine_restart i =
+  let (newi, _) = combine i No_alloc in newi
+
+let fundecl f =
+  {f with fun_body = combine_restart f.fun_body}
diff --git a/asmcomp/comballoc.mli b/asmcomp/comballoc.mli
new file mode 100644
index 000000000..903c1605c
--- /dev/null
+++ b/asmcomp/comballoc.mli
@@ -0,0 +1,16 @@
+(***********************************************************************)
+(*                                                                     *)
+(*                           Objective Caml                            *)
+(*                                                                     *)
+(*            Xavier Leroy, projet Cristal, INRIA Rocquencourt         *)
+(*                                                                     *)
+(*  Copyright 1999 Institut National de Recherche en Informatique et   *)
+(*  en Automatique.  Distributed only by permission.                   *)
+(*                                                                     *)
+(***********************************************************************)
+
+(* $Id$ *)
+
+(* Combine heap allocations occurring in the same basic block *)
+
+val fundecl: Mach.fundecl -> Mach.fundecl
diff --git a/asmcomp/selectgen.ml b/asmcomp/selectgen.ml
index 5da131c88..fe4269313 100644
--- a/asmcomp/selectgen.ml
+++ b/asmcomp/selectgen.ml
@@ -44,60 +44,33 @@ let oper_result_type = function
 
 (* Infer the size in bytes of the result of a simple expression *)
 
-let rec size env localenv = function
-    Cconst_int _ | Cconst_natint _ -> Arch.size_int
-  | Cconst_symbol _ | Cconst_pointer _ -> Arch.size_addr
-  | Cconst_float _ -> Arch.size_float
-  | Cvar id ->
-      begin try
-        Tbl.find id localenv
-      with Not_found ->
-      try
-        let regs = Tbl.find id env in
-        size_machtype (Array.map (fun r -> r.typ) regs)
-      with Not_found ->
-        fatal_error("Selection.size_expr: unbound var " ^
-                    Ident.unique_name id)
-      end
-  | Ctuple el ->
-      size_list env localenv el
-  | Cop(op, args) ->
-      size_machtype(oper_result_type op)
-  | Clet(id, arg, body) ->
-      size env (Tbl.add id (size env localenv arg) localenv) body
-  | Csequence(e1, e2) ->
-      size env localenv e2
-  | _ ->
-      fatal_error "Selection.size"
-
-and size_list env localenv el =
-  List.fold_right (fun e sz -> size env localenv e + sz) el 0
-
-let size_expr env exp = size env Tbl.empty exp
-
-(* Compute the total size (in bytes) of memory allocated by
-   a simple expression *)
-
-let rec alloc_sz env localenv = function
-    Ctuple el ->
-      alloc_sz_list env localenv el
-  | Cop(op, args) ->
-      let s = alloc_sz_list env localenv args in
-      begin match op with
-        Calloc -> s + size_list env localenv args
-      | _ -> s
-      end
-  | Clet(id, arg, body) ->
-      alloc_sz env localenv arg +
-      alloc_sz env (Tbl.add id (size env localenv arg) localenv) body
-  | Csequence(e1, e2) ->
-      alloc_sz env localenv e1 + alloc_sz env localenv e2
-  | _ -> 0
-
-and alloc_sz_list env localenv el =
-  List.fold_right (fun e sz -> alloc_sz env localenv e + sz) el 0
-
-let alloc_size env exp = alloc_sz env Tbl.empty exp
+let size_expr env exp =
+  let rec size localenv = function
+      Cconst_int _ | Cconst_natint _ -> Arch.size_int
+    | Cconst_symbol _ | Cconst_pointer _ -> Arch.size_addr
+    | Cconst_float _ -> Arch.size_float
+    | Cvar id ->
+        begin try
+          Tbl.find id localenv
+        with Not_found ->
+        try
+          let regs = Tbl.find id env in
+          size_machtype (Array.map (fun r -> r.typ) regs)
+        with Not_found ->
+          fatal_error("Selection.size_expr: unbound var " ^
+                      Ident.unique_name id)
+        end
+    | Ctuple el ->
+        List.fold_right (fun e sz -> size localenv e + sz) el 0
+    | Cop(op, args) ->
+        size_machtype(oper_result_type op)
+    | Clet(id, arg, body) ->
+        size (Tbl.add id (size localenv arg) localenv) body
+    | Csequence(e1, e2) ->
+        size localenv e2
+    | _ ->
+        fatal_error "Selection.size_expr"
+  in size Tbl.empty exp
 
 (* Says if an expression is "simple". A "simple" expression has no
    side-effects and its execution can be delayed until its value
@@ -119,7 +92,7 @@ let rec is_simple_expr = function
   | Cop(op, args) ->
       begin match op with
         (* The following may have side effects *)
-        Capply _ | Cextcall(_, _, _) | Cstore | Cstorechunk _ | 
+        Capply _ | Cextcall(_, _, _) | Calloc | Cstore | Cstorechunk _ | 
         Craise -> false
         (* The remaining operations are simple if their args are *)
       | _ -> List.for_all is_simple_expr args
@@ -197,11 +170,6 @@ let join_array rs =
     res
   end
 
-(* Addressing mode to refer to the header word of a newly allocated object *)
-
-let header_addressing =
-  Arch.offset_addressing Arch.identity_addressing (-Arch.size_int)
-
 (* The default instruction selection class *)
 
 class virtual selector_generic = object (self)
@@ -357,14 +325,6 @@ method extract =
     else extract (instr_cons i.desc i.arg i.res res) i.next in
   extract (end_instr()) instr_seq
 
-(* Are we inside a combined allocation? *)
-
-val mutable alloc_state = (None : (Reg.t array * int) option)
-
-(* None: no combined allocation
-   Some(r, n): earlier allocation left result in register [r],
-     current offset in allocated block is [n]. *)
-
 (* Insert a sequence of moves from one pseudoreg set to another. *)
 
 method insert_move src dst =
@@ -491,35 +451,17 @@ method emit_expr env exp =
           Proc.contains_calls := true;
           let rd = Reg.createv typ_addr in
           let size = size_expr env (Ctuple new_args) in
-          begin match alloc_state with
-            None ->
-              let total_size = alloc_size env (Cop(Calloc, new_args)) in
-              self#insert (Iop(Ialloc total_size)) [||] rd;
-              alloc_state <- Some(rd, size);
-              self#emit_stores env new_args rd header_addressing;
-              alloc_state <- None;
-              rd
-          | Some(ralloc, ofs) ->
-              if self#is_immediate ofs then
-                ignore(self#insert_op (Iintop_imm(Iadd, ofs)) ralloc rd)
-              else begin
-                let r = Reg.createv typ_int in
-                ignore(self#insert_op (Iconst_int(Nativeint.from ofs)) [||] r);
-                ignore(self#insert_op (Iintop Iadd)
-                                      (Array.append ralloc r) rd)
-              end;
-              alloc_state <- Some(ralloc, ofs + size);
-              self#emit_stores env new_args ralloc
-                               (Arch.offset_addressing header_addressing ofs);
-              rd
-          end
+          self#insert (Iop(Ialloc size)) [||] rd;
+          self#emit_stores env new_args rd 
+            (Arch.offset_addressing Arch.identity_addressing (-Arch.size_int));
+          rd
       | op ->
           let r1 = self#emit_tuple env new_args in
           let rd = Reg.createv ty in
           self#insert_op op r1 rd
       end        
   | Csequence(e1, e2) ->
-      ignore(self#emit_expr env e1);
+      let _ = self#emit_expr env e1 in
       self#emit_expr env e2
   | Cifthenelse(econd, eif, eelse) ->
       let (cond, earg) = self#select_condition econd in
@@ -695,7 +637,7 @@ method emit_tail env exp =
       self#insert (Iop Imove) r1 rd;
       self#insert Iraise rd [||]
   | Csequence(e1, e2) ->
-      ignore(self#emit_expr env e1);
+      let _ = self#emit_expr env e1 in
       self#emit_tail env e2
   | Cifthenelse(econd, eif, eelse) ->
       let (cond, earg) = self#select_condition econd in