Index: generic/tclExecute.c
==================================================================
--- generic/tclExecute.c
+++ generic/tclExecute.c
@@ -490,11 +490,13 @@
 	}								\
     } while (0)
 
 /*
  * Macro used in this file to save a function call for common uses of
- * TclGetNumberFromObj(). The ANSI C "prototype" is:
+ * TclGetNumberFromObj(). An "unsafe" version is available when objPtr
+ * is known to be of numeric type and valid (non-NAN) value already.
+ * The ANSI C "prototype" is:
  *
  * MODULE_SCOPE int GetNumberFromObj(Tcl_Interp *interp, Tcl_Obj *objPtr,
  *			ClientData *ptrPtr, int *tPtr);
  */
 
@@ -511,10 +513,18 @@
 		*(ptrPtr) = (ClientData)				\
 		    (&((objPtr)->internalRep.doubleValue)), TCL_OK) :	\
     (((objPtr)->bytes != NULL) && ((objPtr)->length == 0))		\
 	? TCL_ERROR :			\
     TclGetNumberFromObj((interp), (objPtr), (ptrPtr), (tPtr)))
+#define GetNumberFromObjUnsafe(objPtr, ptrPtr, tPtr)			\
+    ((objPtr)->typePtr == &tclIntType)					\
+	?	(*(tPtr) = TCL_NUMBER_LONG,				\
+		*(ptrPtr) = (ClientData)				\
+		    (&((objPtr)->internalRep.longValue))) :		\
+		(*(tPtr) = TCL_NUMBER_DOUBLE,				\
+		*(ptrPtr) = (ClientData)				\
+		    (&((objPtr)->internalRep.doubleValue)))
 #else /* !TCL_WIDE_INT_IS_LONG */
 #define GetNumberFromObj(interp, objPtr, ptrPtr, tPtr) \
     (((objPtr)->typePtr == &tclIntType)					\
 	?	(*(tPtr) = TCL_NUMBER_LONG,				\
 		*(ptrPtr) = (ClientData)				\
@@ -530,10 +540,22 @@
 		*(ptrPtr) = (ClientData)				\
 		    (&((objPtr)->internalRep.doubleValue)), TCL_OK) :	\
     (((objPtr)->bytes != NULL) && ((objPtr)->length == 0))		\
 	? TCL_ERROR :			\
     TclGetNumberFromObj((interp), (objPtr), (ptrPtr), (tPtr)))
+#define GetNumberFromObjUnsafe(objPtr, ptrPtr, tPtr)			\
+    ((objPtr)->typePtr == &tclIntType)					\
+	?	(*(tPtr) = TCL_NUMBER_LONG,				\
+		*(ptrPtr) = (ClientData)				\
+		    (&((objPtr)->internalRep.longValue))) :		\
+    ((objPtr)->typePtr == &tclWideIntType)				\
+	?	(*(tPtr) = TCL_NUMBER_WIDE,				\
+		*(ptrPtr) = (ClientData)				\
+		    (&((objPtr)->internalRep.wideValue))) :		\
+		(*(tPtr) = TCL_NUMBER_DOUBLE,				\
+		*(ptrPtr) = (ClientData)				\
+		    (&((objPtr)->internalRep.doubleValue)))
 #endif /* TCL_WIDE_INT_IS_LONG */
 
 /*
  * Macro used in this file to save a function call for common uses of
  * Tcl_GetBooleanFromObj(). The ANSI C "prototype" is:
@@ -8160,12 +8182,12 @@
     mp_int big1, big2, bigResult, bigRemainder;
     Tcl_Obj *objResultPtr;
     int invalid, numPos, zero;
     long shift;
 
-    (void) GetNumberFromObj(NULL, valuePtr, &ptr1, &type1);
-    (void) GetNumberFromObj(NULL, value2Ptr, &ptr2, &type2);
+    GetNumberFromObjUnsafe(valuePtr, &ptr1, &type1);
+    GetNumberFromObjUnsafe(value2Ptr, &ptr2, &type2);
 
     switch (opcode) {
     case INST_MOD:
 	/* TODO: Attempts to re-use unshared operands on stack */
 
@@ -9155,11 +9177,11 @@
     int type;
     Tcl_WideInt w;
     mp_int big;
     Tcl_Obj *objResultPtr;
 
-    (void) GetNumberFromObj(NULL, valuePtr, &ptr, &type);
+    GetNumberFromObjUnsafe(valuePtr, &ptr, &type);
 
     switch (opcode) {
     case INST_BITNOT:
 #ifndef TCL_WIDE_INT_IS_LONG
 	if (type == TCL_NUMBER_WIDE) {
@@ -9237,12 +9259,12 @@
     long l1, l2;
 #ifndef TCL_WIDE_INT_IS_LONG
     Tcl_WideInt w1, w2;
 #endif
 
-    (void) GetNumberFromObj(NULL, valuePtr, &ptr1, &type1);
-    (void) GetNumberFromObj(NULL, value2Ptr, &ptr2, &type2);
+    GetNumberFromObjUnsafe(valuePtr, &ptr1, &type1);
+    GetNumberFromObjUnsafe(value2Ptr, &ptr2, &type2);
 
     switch (type1) {
     case TCL_NUMBER_LONG:
 	l1 = *((const long *)ptr1);
 	switch (type2) {