void Cpl()
{
      *(volatile uint32_t *)ODR_BB_ADDR = ~*(volatile uint32_t *)ODR_BB_ADDR;
}

void LED_Blink(void) {
  while (1) {
    GPIOB->BSRR = 0x0002;
//    __nop(), __nop(), __nop;
    GPIOB->BRR = 0x0002;
  }
}

...
#define _PIN_SET(   XPORT, XPIN, XMODE, XSPEED)  do {GPIO##XPORT->BSRR = (1UL << (XPIN)); } while (0)  // Atomic operation
#define _PIN_CLR(   XPORT, XPIN, XMODE, XSPEED)  do {GPIO##XPORT->BRR  = (1UL << (XPIN)); } while (0)  // Atomic operation

#define _PIN_TEST(  XPORT, XPIN, XMODE, XSPEED)   ( (GPIO##XPORT->IDR  & (1UL << (XPIN))) != 0UL )

#define _PIN_TOGGLE(XPORT, XPIN, XMODE, XSPEED)                                        \
do                                                                                     \
{                                                                                      \
    if (_PIN_TEST(XPORT, XPIN, XMODE, XSPEED))  _PIN_CLR(XPORT, XPIN, XMODE, XSPEED);  \
    else                                        _PIN_SET(XPORT, XPIN, XMODE, XSPEED);  \
} while (0)

;;;370    void LED_Blink(void) {
000386  482e              LDR      r0,|L1.1088|
;;;371      while (1) {
;;;372        GPIOB->BSRR = 0x0002;
000388  f04f0102          MOV      r1,#2
                  |L1.908|
00038c  f8c01c10          STR      r1,[r0,#0xc10]
;;;373    //    __nop(), __nop(), __nop(); // from Flash 12 clock states
;;;374    //  __nop(), __nop();   // from RAM 14 clock states
;;;375        GPIOB->BRR = 0x0002;
000390  f8c01c14          STR      r1,[r0,#0xc14]
000394  e7fa              B        |L1.908|
;;;376      }
;;;377    }

                  Bit_change1 PROC
;;;68    
;;;69     void Bit_change1(bool set)
000004  b118              CBZ      r0,|L1.14|
;;;70     {
;;;71       if (set) GPIOB->BSRR = 0x0002;
000006  2102              MOVS     r1,#2
000008  4a0f              LDR      r2,|L1.72|
00000a  6011              STR      r1,[r2,#0]
00000c  e002              B        |L1.20|
                  |L1.14|
;;;72       else     GPIOB->BRR  = 0x0002;
00000e  2102              MOVS     r1,#2
000010  4a0e              LDR      r2,|L1.76|
000012  6011              STR      r1,[r2,#0]
                  |L1.20|
;;;73     }
000014  4770              BX       lr
;;;74    
                          ENDP

                  Bit_change2 PROC
;;;75     void Bit_change2(bool set)
000016  b108              CBZ      r0,|L1.28|
;;;76     {
;;;77       GPIOB->BSRR = 0x0002<<(set ? 0 : 16);
000018  2200              MOVS     r2,#0
00001a  e000              B        |L1.30|
                  |L1.28|
00001c  2210              MOVS     r2,#0x10
                  |L1.30|
00001e  2102              MOVS     r1,#2
000020  4091              LSLS     r1,r1,r2
000022  4a09              LDR      r2,|L1.72|
000024  6011              STR      r1,[r2,#0]
;;;78     }
000026  4770              BX       lr
;;;79    
                          ENDP

                  Bit_change3 PROC
;;;80     void Bit_change3(bool set)
000028  b108              CBZ      r0,|L1.46|
;;;81     {
;;;82       GPIOB->BSRR = set ? 0x0002 : 0x0002<<16;
00002a  2102              MOVS     r1,#2
00002c  e001              B        |L1.50|
                  |L1.46|
00002e  f44f3100          MOV      r1,#0x20000
                  |L1.50|
000032  4a05              LDR      r2,|L1.72|
000034  6011              STR      r1,[r2,#0]
;;;83     }
000036  4770              BX       lr
;;;84    
                          ENDP

                  Bit_change4 PROC
;;;91    
;;;92     void Bit_change4()
000038  4905              LDR      r1,|L1.80|
;;;93     {
;;;94     #define ALIAS_PTR(VarPtr,BitNum) \
;;;95       *((__IO uint32_t *) (((uint32_t) &(VarPtr) & 0xf0000000) | 0x02000000 \
;;;96       + (((uint32_t) &(VarPtr) & 0xfffff) <<5) | (BitNum <<2)))
;;;97    
;;;98       uint32_t bit = ALIAS_PTR(GPIOB->ODR,1);
00003a  6808              LDR      r0,[r1,#0]
;;;99       bit = !bit;
00003c  b908              CBNZ     r0,|L1.66|
00003e  2101              MOVS     r1,#1
000040  e000              B        |L1.68|
                  |L1.66|
000042  2100              MOVS     r1,#0
                  |L1.68|
000044  4608              MOV      r0,r1
;;;100    }
000046  4770              BX       lr
;;;101    
                          ENDP

                  |L1.72|
                          DCD      0x40010c10
                  |L1.76|
                          DCD      0x40010c14
                  |L1.80|
                          DCD      0x42218184