diff --git a/C/absmi.c b/C/absmi.c
index 232d161df..807f55968 100644
--- a/C/absmi.c
+++ b/C/absmi.c
@@ -902,9 +902,9 @@ Yap_absmi(int inp)
 #ifdef YAPOR
       SCH_set_load(B_YREG);
 #endif	/* YAPOR */
+      PREG = NEXTOP(PREG, Otapl);
       SET_BB(B_YREG);
       ENDCACHE_Y();
-      PREG = NEXTOP(PREG, Otapl);
       GONext();
       ENDOp();
 
@@ -2023,7 +2023,7 @@ Yap_absmi(int inp)
 #endif	/* LOW_LEVEL_TRACER */
 #ifdef FROZEN_STACKS
 #ifdef YAPOR_SBA
-	  if (pt0 < TR_FZ || pt0 > (tr_fr_ptr)LOCAL_TrailTop)
+	  if (pt0 < TR_FZ || pt0 > CurrentTrailTop)
 #else
 	  if (pt0 < TR_FZ)
 #endif /* YAPOR_SBA */
@@ -2073,7 +2073,7 @@ Yap_absmi(int inp)
 #ifdef YAPOR_SBA
 		(ADDR) pt1 >= HeapTop
 #else
-		IN_BETWEEN(LOCAL_TrailBase, pt1, LOCAL_TrailTop)
+		IN_BETWEEN(LOCAL_TrailBase, pt1, CurrentTrailTop)
 #endif /* YAPOR_SBA */
 		)
             {
diff --git a/C/exec.c b/C/exec.c
index 89e9dfb13..9c0b37695 100644
--- a/C/exec.c
+++ b/C/exec.c
@@ -1630,6 +1630,7 @@ Yap_InitYaamRegs(void)
   H = H0 = ((CELL *) LOCAL_GlobalBase)+ Yap_AttsSize/sizeof(CELL);
   RESET_VARIABLE(H0-1);
   LCL0 = ASP = (CELL *) LOCAL_LocalBase;
+  CurrentTrailTop = (tr_fr_ptr)LOCAL_TrailTop;
   /* notice that an initial choice-point and environment
    *must* be created since for the garbage collector to work */
   B = NULL;
diff --git a/C/grow.c b/C/grow.c
index 8e8c9e75f..71ebb5c45 100644
--- a/C/grow.c
+++ b/C/grow.c
@@ -125,6 +125,7 @@ SetHeapRegs(int copying_threads USES_REGS)
   /* Adjust stack addresses */
   LOCAL_TrailBase = TrailAddrAdjust(LOCAL_TrailBase);
   LOCAL_TrailTop = TrailAddrAdjust(LOCAL_TrailTop);
+  CurrentTrailTop = (tr_fr_ptr)LOCAL_TrailTop;
   if (LOCAL_GDiff) {
     /* make sure we are not just expanding the delay stack */
     LOCAL_GlobalBase = BaseAddrAdjust(LOCAL_GlobalBase);
@@ -1850,6 +1851,7 @@ Yap_CopyThreadStacks(int worker_q, int worker_p, int incremental)
   LOCAL_LocalBase = REMOTE_LocalBase(worker_p);
   LOCAL_TrailBase = REMOTE_TrailBase(worker_p);
   LOCAL_TrailTop = REMOTE_TrailTop(worker_p);
+  CurrentTrailTop = (tr_fr_ptr)LOCAL_TrailTop;
   size = REMOTE_ThreadHandle(worker_q).stack_address-REMOTE_ThreadHandle(worker_p).stack_address;
   LOCAL_TrDiff = LOCAL_LDiff = LOCAL_GDiff = LOCAL_GDiff0 = LOCAL_DelayDiff = LOCAL_BaseDiff = size;
   LOCAL_XDiff = LOCAL_HDiff = 0;
diff --git a/H/Regs.h b/H/Regs.h
index ee9ccb7ed..849f01512 100644
--- a/H/Regs.h
+++ b/H/Regs.h
@@ -113,6 +113,7 @@ typedef struct regstore_t
     CELL  *ENV_;		/* 1 current environment                      */
     CELL  *ASP_;		/* 8 top of local       stack                 */
     CELL  *LCL0_;		/* 3 local stack base                         */
+    tr_fr_ptr   CurrentTrailTop_;	/* 10 Auxiliary stack top                     */
     ADDR   AuxBase_;		/* 9 Auxiliary base  pointer                  */
     CELL  *AuxSp_;		/* 9 Auxiliary stack pointer                  */
     ADDR   AuxTop_;		/* 10 Auxiliary stack top                     */
@@ -630,6 +631,7 @@ EXTERN inline void restore_B(void) {
 #define	AuxBase       Yap_REGS.AuxBase_
 #define	AuxSp         Yap_REGS.AuxSp_
 #define	AuxTop        Yap_REGS.AuxTop_
+#define	CurrentTrailTop      Yap_REGS.CurrentTrailTop_
 #define EX            Yap_REGS.EX_
 #define DEPTH	      Yap_REGS.DEPTH_
 #if defined(YAPOR_SBA) || defined(TABLING)
diff --git a/H/absmi.h b/H/absmi.h
index 26dfb08ee..9ac2b4163 100644
--- a/H/absmi.h
+++ b/H/absmi.h
@@ -682,10 +682,10 @@ Macros to check the limits of stacks
 
 #else
 
-#define check_trail(x) if (Unsigned(LOCAL_TrailTop) - Unsigned(x) < MinTrailGap) \
+#define check_trail(x) if (Unsigned(CurrentTrailTop) - Unsigned(x) < MinTrailGap) \
 			goto notrailleft
 
-#define check_trail_in_indexing(x) if (Unsigned(LOCAL_TrailTop) - Unsigned(x) < MinTrailGap) \
+#define check_trail_in_indexing(x) if (Unsigned(CurrentTrailTop) - Unsigned(x) < MinTrailGap) \
 			goto notrailleft_from_index
 
 #endif
@@ -733,7 +733,7 @@ Macros to check the limits of stacks
 		 while ( pt0 > XREGS );                           \
                  ENDP(pt0)
 
-#if LOW_LEVEL_TRACER
+#if LOW_LEVEL_TRACER && 0
 #define COUNT_CPS() LOCAL_total_choicepoints++
 #else
 #define COUNT_CPS()