Index: VERSION
===================================================================
--- VERSION	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ VERSION	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -1,4 +1,4 @@
-4.00.0
+4.00.0+xsim-3.1.6
 
 # The version string is the first line of this file.
 # It must be in the format described in stdlib/sys.mli
Index: asmcomp/schedgen.ml
===================================================================
--- asmcomp/schedgen.ml	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ asmcomp/schedgen.ml	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -10,11 +10,10 @@
 (*                                                                     *)
 (***********************************************************************)
 
-(* $Id: schedgen.ml 12179 2012-02-21 17:41:02Z xleroy $ *)
+(* $Id$ *)
 
 (* Instruction scheduling *)
 
-open Misc
 open Reg
 open Mach
 open Linearize
@@ -65,6 +64,33 @@
 
 let add_edge_after son ancestor = add_edge ancestor son 0
 
+(* Add edges from all instructions that define a pseudoregister [arg] being used
+   as argument to node [node] (RAW dependencies *)
+
+let add_RAW_dependencies node arg =
+  try
+    let ancestor = Hashtbl.find code_results arg.loc in
+    add_edge ancestor node ancestor.delay
+  with Not_found ->
+    ()
+
+(* Add edges from all instructions that use a pseudoregister [res] that is
+   defined by node [node] (WAR dependencies). *)
+
+let add_WAR_dependencies node res =
+  let ancestors = Hashtbl.find_all code_uses res.loc in
+  List.iter (add_edge_after node) ancestors
+
+(* Add edges from all instructions that have already defined a pseudoregister
+   [res] that is defined by node [node] (WAW dependencies). *)
+
+let add_WAW_dependencies node res =
+  try
+    let ancestor = Hashtbl.find code_results res.loc in
+    add_edge ancestor node 0
+  with Not_found ->
+    ()
+
 (* Compute length of longest path to a result.
    For leafs of the DAG, see whether their result is used in the instruction
    immediately following the basic block (a "critical" output). *)
@@ -200,10 +226,19 @@
   | Lreloadretaddr -> self#reload_retaddr_issue_cycles
   | _ -> assert false
 
+(* Pseudoregisters destroyed by an instruction *)
+
+method private destroyed_by_instr instr =
+  match instr.desc with
+  | Lop op -> Proc.destroyed_at_oper (Iop op)
+  | Lreloadretaddr -> [||]
+  | _ -> assert false
+
 (* Add an instruction to the code dag *)
 
 method private add_instruction ready_queue instr =
   let delay = self#instr_latency instr in
+  let destroyed = self#destroyed_by_instr instr in
   let node =
     { instr = instr;
       delay = delay;
@@ -214,28 +249,17 @@
       emitted_ancestors = 0 } in
   (* Add edges from all instructions that define one of the registers used
      (RAW dependencies) *)
-  for i = 0 to Array.length instr.arg - 1 do
-    try
-      let ancestor = Hashtbl.find code_results instr.arg.(i).loc in
-      add_edge ancestor node ancestor.delay
-    with Not_found ->
-      ()
-  done;
+  Array.iter (add_RAW_dependencies node) instr.arg;
   (* Also add edges from all instructions that use one of the result regs
-     of this instruction (WAR dependencies). *)
-  for i = 0 to Array.length instr.res - 1 do
-    let ancestors = Hashtbl.find_all code_uses instr.res.(i).loc in
-    List.iter (add_edge_after node) ancestors
-  done;
+     of this instruction, or a reg destroyed by this instruction
+     (WAR dependencies). *)
+  Array.iter (add_WAR_dependencies node) instr.res;
+  Array.iter (add_WAR_dependencies node) destroyed;   (* PR#5731 *)
   (* Also add edges from all instructions that have already defined one
-     of the results of this instruction (WAW dependencies). *)
-  for i = 0 to Array.length instr.res - 1 do
-    try
-      let ancestor = Hashtbl.find code_results instr.res.(i).loc in
-      add_edge ancestor node 0
-    with Not_found ->
-      ()
-  done;
+     of the results of this instruction, or a reg destroyed by
+     this instruction (WAW dependencies). *)
+  Array.iter (add_WAW_dependencies node) instr.res;
+  Array.iter (add_WAW_dependencies node) destroyed;   (* PR#5731 *)
   (* If this is a load, add edges from the most recent store viewed so
      far (if any) and remember the load.  Also add edges from the most
      recent checkbound and forget that checkbound. *)
@@ -264,6 +288,9 @@
   for i = 0 to Array.length instr.res - 1 do
     Hashtbl.add code_results instr.res.(i).loc node
   done;
+  for i = 0 to Array.length destroyed - 1 do
+    Hashtbl.add code_results destroyed.(i).loc node  (* PR#5731 *)
+  done;
   for i = 0 to Array.length instr.arg - 1 do
     Hashtbl.add code_uses instr.arg.(i).loc node
   done;
Index: asmcomp/i386/emit.mlp
===================================================================
--- asmcomp/i386/emit.mlp	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ asmcomp/i386/emit.mlp	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -85,7 +85,14 @@
 let emit_data_label lbl =
   emit_string label_prefix; emit_string "d"; emit_int lbl
 
+(* Emit truncated native int, necessary when cross compiling from 64 to
+ * 32 bit environments.  For the usual self-hosted 32-bit environment
+ * this acts exactly like emit_nativeint.
+ *)
+let emit_t_nativeint n =
+    emit_int32 (Nativeint.to_int32 n)
 
+
 (* Some data directives have different names under Solaris *)
 
 let word_dir =
@@ -451,7 +458,7 @@
             Reg n -> `	xorl	{emit_reg i.res.(0)}, {emit_reg i.res.(0)}\n`
           | _     -> `	movl	$0, {emit_reg i.res.(0)}\n`
         end else
-          `	movl	${emit_nativeint n}, {emit_reg i.res.(0)}\n`
+          `	movl	${emit_t_nativeint n}, {emit_reg i.res.(0)}\n`
     | Lop(Iconst_float s) ->
         begin match Int64.bits_of_float (float_of_string s) with
         | 0x0000_0000_0000_0000L ->       (* +0.0 *)
@@ -685,7 +692,7 @@
     | Lop(Ispecific(Ilea addr)) ->
         `	lea	{emit_addressing addr i.arg 0}, {emit_reg i.res.(0)}\n`
     | Lop(Ispecific(Istore_int(n, addr))) ->
-        `	movl	${emit_nativeint n}, {emit_addressing addr i.arg 0}\n`
+        `	movl	${emit_t_nativeint n}, {emit_addressing addr i.arg 0}\n`
     | Lop(Ispecific(Istore_symbol(s, addr))) ->
         `	movl	${emit_symbol s}, {emit_addressing addr i.arg 0}\n`
     | Lop(Ispecific(Ioffset_loc(n, addr))) ->
@@ -712,7 +719,7 @@
               stack_offset := !stack_offset + 4
         done
     | Lop(Ispecific(Ipush_int n)) ->
-        `	pushl	${emit_nativeint n}\n`;
+        `	pushl	${emit_t_nativeint n}\n`;
         cfi_adjust_cfa_offset 4;
         stack_offset := !stack_offset + 4
     | Lop(Ispecific(Ipush_symbol s)) ->
@@ -961,9 +968,9 @@
   | Cint16 n ->
       `	{emit_string word_dir}	{emit_int n}\n`
   | Cint32 n ->
-      `	.long	{emit_nativeint n}\n`
+      `	.long	{emit_t_nativeint n}\n`
   | Cint n ->
-      `	.long	{emit_nativeint n}\n`
+      `	.long	{emit_t_nativeint n}\n`
   | Csingle f ->
       emit_float32_directive ".long" f
   | Cdouble f ->

Index: tools/make-package-macosx
===================================================================
--- tools/make-package-macosx	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ tools/make-package-macosx	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -30,9 +30,9 @@
           <key>IFPkgDescriptionDeleteWarning</key>
           <string></string>
           <key>IFPkgDescriptionDescription</key>
-          <string>The OCaml compiler and tools</string>
+          <string>The OCaml compiler and tools for iOS Simulator</string>
           <key>IFPkgDescriptionTitle</key>
-          <string>OCaml</string>
+          <string>OCaml for iOS Simulator</string>
           <key>IFPkgDescriptionVersion</key>
           <string>${VERSION}</string>
   </dict>
@@ -46,11 +46,11 @@
 <plist version="1.0">
 <dict>
         <key>CFBundleGetInfoString</key>
-        <string>OCaml ${VERSION}</string>
+        <string>OCaml ${VERSION} for iOS Simulator</string>
         <key>CFBundleIdentifier</key>
-        <string>fr.inria.ocaml</string>
+        <string>com.psellos.ocamlxsim</string>
         <key>CFBundleName</key>
-        <string>OCaml</string>
+        <string>OCaml iOSSim</string>
         <key>CFBundleShortVersionString</key>
         <string>${VERSION}</string>
         <key>IFMajorVersion</key>
@@ -62,7 +62,7 @@
         <key>IFPkgFlagAuthorizationAction</key>
         <string>AdminAuthorization</string>
         <key>IFPkgFlagDefaultLocation</key>
-        <string>/usr/local</string>
+        <string>/usr/local/ocamlxsim</string>
         <key>IFPkgFlagInstallFat</key>
         <false/>
         <key>IFPkgFlagIsRequired</key>
@@ -85,15 +85,16 @@
 
 #                                         stop here -> |
 cat >resources/ReadMe.txt <<EOF
-This package installs OCaml version ${VERSION}.
-You need Mac OS X 10.7.x (Lion), with the
-XCode tools installed (v3.2.6 or later).
+This package installs OCaml version ${VERSION},
+for cross compiling to the iOS Simulator.
+You need Mac OS X 10.7.x (Lion) or later, with the
+XCode tools installed (v4.2 or later).
 
 Files will be installed in the following directories:
 
-/usr/local/bin - command-line executables
-/usr/local/lib/ocaml - library and support files
-/usr/local/man - manual pages
+/usr/local/ocamlxsim/bin - command-line executables
+/usr/local/ocamlxsim/lib/ocaml - library and support files
+/usr/local/ocamlxsim/man - manual pages
 
 Note that this package installs only command-line
 tools and does not include any GUI application.
@@ -102,7 +103,7 @@
 chmod -R g-w root
 sudo chown -R root:wheel root
 
-/Developer/Applications/Utilities/PackageMaker.app/Contents/MacOS/PackageMaker \
+/Developer/Auxiliary\ Tools/PackageMaker.app/Contents/MacOS/PackageMaker \
   -build -p "`pwd`/ocaml.pkg" -f "`pwd`/root" -i "`pwd`/Info.plist" \
   -d "`pwd`/Description.plist" -r "`pwd`/resources"
 

Index: xsim-build
===================================================================
--- xsim-build	(.../vendor/ocaml/4.00.0)	(revision 0)
+++ xsim-build	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -0,0 +1,169 @@
+#!/bin/sh
+#
+# Build OCamlXSim, OCaml cross-compiler for iOS Simulator, based on
+# OCaml 4.00.0
+#
+# Jeffrey Scofield, jeffsco@psellos.com
+#
+# Copyright (c) 2012 Psellos   http://psellos.com/
+# Licensed under the MIT License:
+#     http://www.opensource.org/licenses/mit-license.php
+#
+# Page of OCaml-on-iOS resources: http://psellos.com/ocaml/
+#
+# Expects one parameter:
+# Single big step:  all
+# Medium steps:     phase1           phase2
+# Small steps:      config1  build1  config2  build2
+
+# We use fancy features of the sed that comes with OS X.  For now,
+# specify full path.  If this becomes a problem, stop using the fancy
+# features.
+#
+SED=/usr/bin/sed
+
+export PLT=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneSimulator.platform
+export SDK=/Developer/SDKs/iPhoneSimulator5.1.sdk
+export XSIMTARGET=/usr/local/ocamlxsim
+export OSXARCH=i386
+
+# Small steps
+config1 () {
+    # Configure for building bytecode interpreter to run on Intel OS X.
+    # But specify iOSSim parameters for assembly and partial link.
+    echo 'xsim-build: ----- configure phase 1 -----'
+    ./configure \
+            -bindir $XSIMTARGET/bin \
+            -libdir $XSIMTARGET/lib/ocaml \
+            -mandir $XSIMTARGET/man/man1 \
+            -no-curses \
+            -no-tk \
+            -no-graph \
+            -host i386-apple-darwin11.3.0 \
+            -cc "gcc -arch $OSXARCH" \
+            -as "$PLT/Developer/usr/bin/gcc -arch i386 -c" \
+            -aspp "$PLT/Developer/usr/bin/gcc -arch i386 -c"
+    # Post-modify config/Makefile to select i386 back end for ocamlopt
+    # (i386 assembly code).
+    $SED -i .bak \
+        -e '1i\
+# modified by xsim-build for OCamlXSim' \
+        -e 's/^ARCH[    ]*=.*/ARCH=i386/' \
+        -e 's/^MODEL[    ]*=.*/MODEL=default/' \
+        -e "s#^PARTIALLD[    ]*=.*#PARTIALLD=$PLT/Developer/usr/bin/ld -r#" \
+        config/Makefile
+    # Post-modify utils/config.ml
+    make utils/config.ml
+    $SED -i .bak \
+        -e 's#let[ 	][ 	]*mkexe[ 	]*=.*#let mkexe ="'"$PLT/Developer/usr/bin/gcc -arch i386 -Wl,-objc_abi_version,2 -Wl,-no_pie -gdwarf-2 -isysroot $PLT$SDK"'"#' \
+        -e 's#let[ 	][ 	]*bytecomp_c_compiler[ 	]*=.*#let bytecomp_c_compiler ="'"$PLT/Developer/usr/bin/gcc -arch i386 -gdwarf-2 -isysroot $PLT$SDK"'"#' \
+        -e 's#let[ 	][ 	]*native_c_compiler[ 	]*=.*#let native_c_compiler ="'"$PLT/Developer/usr/bin/gcc -arch i386 -gdwarf-2 -isysroot $PLT$SDK"'"#' \
+        utils/config.ml
+}
+
+build1 () {
+    echo 'xsim-build: ----- build phase 1 -----'
+    # Don't assemble asmrun/i386.S for Phase 1 build.  Modify
+    # asmrun/Makefile temporarily to disable.  Be really sure to put
+    # back for Phase 2.
+    trap 'mv -f asmrun/Makefile.aside asmrun/Makefile' EXIT
+    grep -q '^[ 	]*ASMOBJS[ 	]*=' asmrun/Makefile && \
+        mv -f asmrun/Makefile asmrun/Makefile.aside
+    $SED -e '/^[ 	]*ASMOBJS[ 	]*=/s/^/#/' \
+        asmrun/Makefile.aside > asmrun/Makefile
+    make world && make opt
+    mv -f asmrun/Makefile.aside asmrun/Makefile
+    trap - EXIT
+    # Save the Phase 1 shared (dynamically loadable) libraries and
+    # restore them after Phase 2.  They're required by some OCaml
+    # utilities, such as camlp4.
+    #
+    # The shared libraries are useful only with the bytecode
+    # interpreter, which we don't support under iOS.  This lets us (just
+    # barely) fit OCamlXSim into the form of a usual OCaml release.
+    find . -name '*.so' -exec mv {} {}phase1 \;
+}
+
+config2 () {
+    # Clean out OS X runtime
+    echo 'xsim-build: ----- configure phase 2 -----'
+    cd asmrun; make clean; cd ..
+    cd stdlib; make clean; cd ..
+    cd otherlibs/bigarray; make clean; cd ../..
+    cd otherlibs/dynlink; make clean; cd ../..
+    cd otherlibs/num; make clean; cd ../..
+    cd otherlibs/str; make clean; cd ../..
+    cd otherlibs/systhreads; make clean; cd ../..
+    cd otherlibs/threads; make clean; cd ../..
+    cd otherlibs/unix; make clean; cd ../..
+    # Reconfigure for iOSSim environment
+    ./configure \
+            -bindir $XSIMTARGET/bin \
+            -libdir $XSIMTARGET/lib/ocaml \
+            -mandir $XSIMTARGET/man/man1 \
+            -no-curses \
+            -no-tk \
+            -no-graph \
+            -host i386-apple-darwin10.0.0d3 \
+            -cc "$PLT/Developer/usr/bin/gcc -arch i386 -gdwarf-2 -isysroot $PLT$SDK" \
+            -as "$PLT/Developer/usr/bin/gcc -arch i386 -c" \
+            -aspp "$PLT/Developer/usr/bin/gcc -arch i386 -c"
+    # Rebuild ocamlmklib, so libraries work with iOSSim.
+    rm myocamlbuild_config.ml
+    cd tools
+    make ocamlmklib
+    cd ..
+}
+
+build2 () {
+    # Make iOSSim runtime
+    echo 'xsim-build: ----- build phase 2 -----'
+    cd asmrun; make all; cd ..
+    cd stdlib; make all allopt; cd ..
+    cd otherlibs/unix; make all allopt; cd ../..
+    cd otherlibs/str; make all allopt; cd ../..
+    cd otherlibs/num; make all allopt; cd ../..
+    cd otherlibs/dynlink; make all allopt; cd ../..
+    cd otherlibs/bigarray; make all allopt; cd ../..
+    cd otherlibs/systhreads; make all allopt; cd ../..
+    cd otherlibs/threads; make all allopt; cd ../..
+    # Restore the saved Phase 1 .so files (see above).
+    find . -name '*.sophase1' -print | \
+        while read f; do \
+            fso="$(expr "$f" : '\(.*\)sophase1$')so"; mv -f $f $fso; \
+        done
+}
+
+# Bigger steps
+
+phase1 () {
+    config1 && build1
+}
+
+phase2 () {
+    config2 && build2
+}
+
+all () {
+    phase1 && phase2
+}
+
+clean () {
+    rm -f myocamlbuild_config.ml
+    make clean
+}
+
+case "$1" in
+config1) config1 ;;
+build1) build1 ;;
+config2) config2 ;;
+build2) build2 ;;
+phase1) phase1 ;;
+phase2) phase2 ;;
+all) all ;;
+clean) clean ;;
+*) echo "usage: $(basename $0) {all|phase1|phase2|config1|build1|config2|build2}" >&2;
+   echo "       $(basename $0) clean" >&2;
+   exit 1
+   ;;
+esac

Index: Makefile
===================================================================
--- Makefile	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ Makefile	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -762,7 +762,10 @@
 
 package-macosx:
 	sudo rm -rf package-macosx/root
-	$(MAKE) PREFIX="`pwd`"/package-macosx/root install
+	$(MAKE) BINDIR="`pwd`"/package-macosx/root/bin \
+		LIBDIR="`pwd`"/package-macosx/root/lib/ocaml \
+		MANDIR="`pwd`"/package-macosx/root/man \
+		install
 	tools/make-package-macosx
 	sudo rm -rf package-macosx/root
 

Index: byterun/intern.c
===================================================================
--- byterun/intern.c	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ byterun/intern.c	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -558,7 +558,7 @@
     Assert(intern_dest <= end_extra_block);
     if (intern_dest < end_extra_block){
       caml_make_free_blocks ((value *) intern_dest,
-                             end_extra_block - intern_dest, 0);
+                             end_extra_block - intern_dest, 0, Caml_white);
     }
     caml_allocated_words +=
       Wsize_bsize ((char *) intern_dest - intern_extra_block);
Index: byterun/memory.c
===================================================================
--- byterun/memory.c	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ byterun/memory.c	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -318,7 +318,7 @@
   }
   remain = malloc_request;
   prev = hp = mem;
-  /* XXX find a way to do this with a call to caml_make_free_blocks */
+  /* FIXME find a way to do this with a call to caml_make_free_blocks */
   while (Wosize_bhsize (remain) > Max_wosize){
     Hd_hp (hp) = Make_header (Max_wosize, 0, Caml_blue);
 #ifdef DEBUG
Index: byterun/freelist.c
===================================================================
--- byterun/freelist.c	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ byterun/freelist.c	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -509,8 +509,11 @@
    p: pointer to the first word of the block
    size: size of the block (in words)
    do_merge: 1 -> do merge; 0 -> do not merge
+   color: which color to give to the pieces; if [do_merge] is 1, this
+          is overridden by the merge code, but we have historically used
+          [Caml_white].
 */
-void caml_make_free_blocks (value *p, mlsize_t size, int do_merge)
+void caml_make_free_blocks (value *p, mlsize_t size, int do_merge, int color)
 {
   mlsize_t sz;
 
@@ -520,7 +523,7 @@
     }else{
       sz = size;
     }
-    *(header_t *)p = Make_header (Wosize_whsize (sz), 0, Caml_white);
+    *(header_t *)p = Make_header (Wosize_whsize (sz), 0, color);
     if (do_merge) caml_fl_merge_block (Bp_hp (p));
     size -= sz;
     p += sz;
Index: byterun/freelist.h
===================================================================
--- byterun/freelist.h	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ byterun/freelist.h	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -29,7 +29,7 @@
 void caml_fl_reset (void);
 char *caml_fl_merge_block (char *);
 void caml_fl_add_blocks (char *);
-void caml_make_free_blocks (value *, mlsize_t, int);
+void caml_make_free_blocks (value *, mlsize_t, int, int);
 void caml_set_allocation_policy (uintnat);
 
 
Index: byterun/compact.c
===================================================================
--- byterun/compact.c	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ byterun/compact.c	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -331,7 +331,7 @@
         word q = *p;
         if (Color_hd (q) == Caml_white){
           size_t sz = Bhsize_hd (q);
-          char *newadr = compact_allocate (sz);  Assert (newadr <= (char *)p);
+          char *newadr = compact_allocate (sz);
           memmove (newadr, p, sz);
           p += Wsize_bsize (sz);
         }else{
@@ -384,7 +384,8 @@
     while (ch != NULL){
       if (Chunk_size (ch) > Chunk_alloc (ch)){
         caml_make_free_blocks ((value *) (ch + Chunk_alloc (ch)),
-                               Wsize_bsize (Chunk_size(ch)-Chunk_alloc(ch)), 1);
+                               Wsize_bsize (Chunk_size(ch)-Chunk_alloc(ch)), 1,
+                               Caml_white);
       }
       ch = Chunk_next (ch);
     }
@@ -397,7 +398,7 @@
 
 void caml_compact_heap (void)
 {
-  uintnat target_size, live;
+  uintnat target_words, target_size, live;
 
   do_compaction ();
   /* Compaction may fail to shrink the heap to a reasonable size
@@ -414,26 +415,33 @@
      See PR#5389
   */
   /* We compute:
-     freewords = caml_fl_cur_size          (exact)
-     heapsize = caml_heap_size             (exact)
-     live = heap_size - freewords
-     target_size = live * (1 + caml_percent_free / 100)
-                 = live / 100 * (100 + caml_percent_free)
-     We add 1 to live/100 to make sure it isn't 0.
+     freewords = caml_fl_cur_size                  (exact)
+     heapwords = Wsize_bsize (caml_heap_size)      (exact)
+     live = heapwords - freewords
+     wanted = caml_percent_free * (live / 100 + 1) (same as in do_compaction)
+     target_words = live + wanted
+     We add one page to make sure a small difference in counting sizes
+     won't make [do_compaction] keep the second block (and break all sorts
+     of invariants).
 
      We recompact if target_size < heap_size / 2
   */
-  live = caml_stat_heap_size - Bsize_wsize (caml_fl_cur_size);
-  target_size = (live / 100 + 1) * (100 + caml_percent_free);
-  target_size = caml_round_heap_chunk_size (target_size);
+  live = Wsize_bsize (caml_stat_heap_size) - caml_fl_cur_size;
+  target_words = live + caml_percent_free * (live / 100 + 1)
+                 + Wsize_bsize (Page_size);
+  target_size = caml_round_heap_chunk_size (Bsize_wsize (target_words));
   if (target_size < caml_stat_heap_size / 2){
     char *chunk;
 
-    /* round it up to a page size */
+    caml_gc_message (0x10, "Recompacting heap (target=%luk)\n",
+                     target_size / 1024);
+
     chunk = caml_alloc_for_heap (target_size);
     if (chunk == NULL) return;
+    /* PR#5757: we need to make the new blocks blue, or they won't be
+       recognized as free by the recompaction. */
     caml_make_free_blocks ((value *) chunk,
-                           Wsize_bsize (Chunk_size (chunk)), 0);
+                           Wsize_bsize (Chunk_size (chunk)), 0, Caml_blue);
     if (caml_page_table_add (In_heap, chunk, chunk + Chunk_size (chunk)) != 0){
       caml_free_for_heap (chunk);
       return;
@@ -448,6 +456,7 @@
     do_compaction ();
     Assert (caml_stat_heap_chunks == 1);
     Assert (Chunk_next (caml_heap_start) == NULL);
+    Assert (caml_stat_heap_size == Chunk_size (chunk));
   }
 }
 
Index: byterun/major_gc.c
===================================================================
--- byterun/major_gc.c	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ byterun/major_gc.c	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -496,7 +496,7 @@
 
   caml_fl_init_merge ();
   caml_make_free_blocks ((value *) caml_heap_start,
-                         Wsize_bsize (caml_stat_heap_size), 1);
+                         Wsize_bsize (caml_stat_heap_size), 1, Caml_white);
   caml_gc_phase = Phase_idle;
   gray_vals_size = 2048;
   gray_vals = (value *) malloc (gray_vals_size * sizeof (value));

Index: testsuite/tests/regression/pr5757/pr5757.ml
===================================================================
--- testsuite/tests/regression/pr5757/pr5757.ml	(.../vendor/ocaml/4.00.0)	(revision 0)
+++ testsuite/tests/regression/pr5757/pr5757.ml	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -0,0 +1,5 @@
+Random.init 3;;
+for i = 0 to 100_000 do
+  ignore (String.create (Random.int 1_000_000))
+done;;
+Printf.printf "hello world\n";;
Index: testsuite/tests/regression/pr5757/pr5757.reference
===================================================================
--- testsuite/tests/regression/pr5757/pr5757.reference	(.../vendor/ocaml/4.00.0)	(revision 0)
+++ testsuite/tests/regression/pr5757/pr5757.reference	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -0,0 +1 @@
+hello world
Index: testsuite/tests/regression/pr5757/Makefile
===================================================================
--- testsuite/tests/regression/pr5757/Makefile	(.../vendor/ocaml/4.00.0)	(revision 0)
+++ testsuite/tests/regression/pr5757/Makefile	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -0,0 +1,4 @@
+MAIN_MODULE=pr5757
+
+include ../../../makefiles/Makefile.one
+include ../../../makefiles/Makefile.common

Index: asmrun/signals_osdep.h
===================================================================
--- asmrun/signals_osdep.h	(.../vendor/ocaml/4.00.0)	(revision 90)
+++ asmrun/signals_osdep.h	(.../trunk/ocamlxsim/3.1)	(revision 90)
@@ -34,7 +34,7 @@
 
 /****************** AMD64, MacOSX */
 
-#elif defined(TARGET_amd64) && defined (SYS_macosx)
+#elif (defined(TARGET_amd64) || (defined(TARGET_i386) && defined(__x86_64))) && defined (SYS_macosx)
 
   #define DECLARE_SIGNAL_HANDLER(name) \
     static void name(int sig, siginfo_t * info, void * context)