Bug 6875 – floating point %= trashes register EAX

With dmd 2.056: void main() { float g = 4; float f = 4; float *p = &f; *p %= g; assert(f == 0); } causes a crash at runtime or the assertion to fail. This is caused by the %= implementation changing the AX register unexpectedly: float *p = &f; 0040201E lea eax,[f] 00402021 mov dword ptr [p],eax *p %= g; 00402024 mov ecx,dword ptr fs:[2Ch] 0040202B mov edx,dword ptr [ecx] 0040202D fld dword ptr [edx+4] 00402033 fld dword ptr [eax] 00402035 fprem 00402037 fnstsw ax 00402039 sahf 0040203A jp D main+25h (402035h) 0040203C fstp st(1) 0040203E fstp dword ptr [eax]

Fixed in 2.059/1.073 head https://github.com/D-Programming-Language/dmd/pull/759 https://github.com/D-Programming-Language/dmd/commit/1d1bc367c131144e764d9fb81c36651407e3337d https://github.com/D-Programming-Language/dmd/commit/9fcab1292ec59b04a458f9ccc90736c500a52bf3