warning: C4017W: __x__1 may be used before being set

1. In my code whenever I set optimization level 3 with time, i got warning:

"warning: C4017W: __x__1 may be used before being set"

2. In the file in which this error, I have included "math.h"

3. When I remove "math.h", warning gets removed.

4. Tool Version Numbers:

Toolchain: MDK-Lite Version: 4.72.1.0
Toolchain Path: C:\Keil\ARM\ARMCC\bin\
C Compiler: Armcc.Exe V5.03.0.76 [Evaluation]
Assembler: Armasm.Exe V5.03.0.76 [Evaluation]
Linker/Locator: ArmLink.Exe V5.03.0.76 [Evaluation]
Librarian: ArmAr.Exe V5.03.0.76 [Evaluation]
Hex Converter: FromElf.Exe V5.03.0.76 [Evaluation]
CPU DLL: SARMCM3.DLL V4.72.1.0
Dialog DLL: DCM.DLL V1.10.0.0
Target DLL: UL2CM3.DLL V1.150.11.0
Dialog DLL: TCM.DLL V1.14.1.0