FPU problem

When I enable FPU in compiler option,My equation result is wrong. 0 + 0 = 0 but I see -107374176 ! (byte view: 0xCCCCCCCC)

Code:

typedef struct
{
uint16_t year;
uint8_t  tA;
uint8_t  tB;
uint8_t  tc;
float    fl1;
float    fl2;
}mStruct;

in my function:
{
mStruct g1,g2;
.
.
myload(&g1);
.
g.fl1+= g.fl1 + paramIn;

.
.
.
}

RTOS is used too(RTX with cmsis_os).
Everything is OK without FPU option.

What is wrong?

Thanks.