diff --git a/vm/cpu-ppc.S b/vm/cpu-ppc.S
index ba539c1fdc..295fffa1a5 100644
--- a/vm/cpu-ppc.S
+++ b/vm/cpu-ppc.S
@@ -173,9 +173,7 @@ DEF(void,throw_impl,(CELL quot, F_STACK_FRAME *rewind_to)):
 DEF(void,lazy_jit_compile,(CELL quot)):
 	mr r4,r1           /* save stack pointer */
 	PROLOGUE
-	SAVE(r3,18)        /* save quot */
 	bl MANGLE(jit_compile)
-	RESTORE(r3,18)
 	EPILOGUE
         JUMP_QUOT          /* call the quotation */
 
diff --git a/vm/cpu-x86.32.S b/vm/cpu-x86.32.S
index 19a735ec88..d8630ce9b3 100644
--- a/vm/cpu-x86.32.S
+++ b/vm/cpu-x86.32.S
@@ -20,7 +20,7 @@ and the callstack top is passed in EDX */
 	pop %ebp ; \
 	pop %ebx
 
-#define QUOT_XT_OFFSET 5
+#define QUOT_XT_OFFSET 9
 #define PROFILING_OFFSET 25
 #define WORD_DEF_OFFSET 13
 #define WORD_XT_OFFSET 29
diff --git a/vm/cpu-x86.64.S b/vm/cpu-x86.64.S
index 1725c0cbd5..6cddb7e53b 100644
--- a/vm/cpu-x86.64.S
+++ b/vm/cpu-x86.64.S
@@ -20,7 +20,7 @@
 	pop %rbp ; \
 	pop %rbx
 
-#define QUOT_XT_OFFSET 13
+#define QUOT_XT_OFFSET 21
 #define PROFILING_OFFSET 53
 #define WORD_DEF_OFFSET 29
 #define WORD_XT_OFFSET 61
diff --git a/vm/jit.c b/vm/jit.c
index d10f25c325..6faf0a6a17 100644
--- a/vm/jit.c
+++ b/vm/jit.c
@@ -34,10 +34,12 @@ bool jit_stack_frame_p(F_ARRAY *array)
 	return false;
 }
 
-FASTCALL void jit_compile(CELL tagged, F_STACK_FRAME *stack)
+FASTCALL CELL jit_compile(CELL tagged, F_STACK_FRAME *stack)
 {
 	stack_chain->callstack_top = stack;
 
+	REGISTER_ROOT(tagged);
+
 	F_QUOTATION *quot = untag_quotation(tagged);
 	F_ARRAY *array = untag_object(quot->array);
 
@@ -154,6 +156,9 @@ FASTCALL void jit_compile(CELL tagged, F_STACK_FRAME *stack)
 	UNREGISTER_UNTAGGED(quot);
 	quot->xt = xt;
 	quot->compiled = T;
+
+	UNREGISTER_ROOT(tagged);
+	return tagged;
 }
 
 XT quot_offset_to_pc(F_QUOTATION *quot, F_FIXNUM offset)
diff --git a/vm/jit.h b/vm/jit.h
index 26a67490f4..a9f1399472 100644
--- a/vm/jit.h
+++ b/vm/jit.h
@@ -1,2 +1,2 @@
-DLLEXPORT FASTCALL void jit_compile(CELL tagged, F_STACK_FRAME *stack);
+DLLEXPORT FASTCALL CELL jit_compile(CELL tagged, F_STACK_FRAME *stack);
 XT quot_offset_to_pc(F_QUOTATION *quot, F_FIXNUM offset);