ARM-GCC: Unsigned-Integer-Overflow

#include <stdint.h>

#include <limits.h>

void do_some_fast_operation_with_nebeneffekt (void);

uint32_t v = UINT32_MAX/10;

void test1 (void) {

  static uint32_t a = 0;

  uint32_t* ap = &a;

  uint32_t* vp = &v;

  __asm__ volatile (  "ldr r0, [%[ap]]\n"

            "ldr r1, [%[vp]]\n"

            "adds r0, r1\n"

            "it cs\n"

            "blcs do_some_fast_operation_with_nebeneffekt\n"

            : 

            : [ap] "r" (ap), [vp] "r" (vp)

            : "r0", "r1", "r2", "r3", "lr", "r12", "cc", "memory");

  a += v;

}

void test2 (void) {

  static uint32_t a = 0;

    if( a > UINT32_MAX - v )

        do_some_fast_operation_with_nebeneffekt();

    a += v;

}

00000000 <test1>:

   0:  b530        push  {r4, r5, lr}

   2:  4c06        ldr  r4, [pc, #24]  ; (1c <test1+0x1c>)

   4:  4d06        ldr  r5, [pc, #24]  ; (20 <test1+0x20>)

   6:  6820        ldr  r0, [r4, #0]

   8:  6829        ldr  r1, [r5, #0]

   a:  1840        adds  r0, r0, r1

   c:  bf28        it  cs

   e:  f7ff fffe   blcs  0 <do_some_fast_operation_with_nebeneffekt>

  12:  6823        ldr  r3, [r4, #0]

  14:  682a        ldr  r2, [r5, #0]

  16:  4413        add  r3, r2

  18:  6023        str  r3, [r4, #0]

  1a:  bd30        pop  {r4, r5, pc}

  ...

00000024 <test2>:

  24:  b538        push  {r3, r4, r5, lr}

  26:  4d07        ldr  r5, [pc, #28]  ; (44 <test2+0x20>)

  28:  4c07        ldr  r4, [pc, #28]  ; (48 <test2+0x24>)

  2a:  682a        ldr  r2, [r5, #0]

  2c:  6863        ldr  r3, [r4, #4]

  2e:  43d1        mvns  r1, r2

  30:  4299        cmp  r1, r3

  32:  d203        bcs.n  3c <test2+0x18>

  34:  f7ff fffe   bl  0 <do_some_fast_operation_with_nebeneffekt>

  38:  682a        ldr  r2, [r5, #0]

  3a:  6863        ldr  r3, [r4, #4]

  3c:  4413        add  r3, r2

  3e:  6063        str  r3, [r4, #4]

  40:  bd38        pop  {r3, r4, r5, pc}

  42:  bf00        nop

  ...