Infinite loop - bug?

Hi,

the do-while loop in the following code segment won't terminate in release mode.

(Windows 7, Visual Studio 2013, ICL version 15.0.3.208 Build 20150407)

unsigned short arr[256];
signed char index = SCHAR_MIN;
do {
	arr[(unsigned char)index] = (unsigned short)index;
} while(index++ < SCHAR_MAX);

Compiled in release mode with:

/GS /W3 /Gy /Zc:wchar_t /Zi /O2 /Ob2 /Fd"x64\Release\vc120.pdb" /Quse-intel-optimized-headers /D "_HAS_EXCEPTIONS=0" /D "_WIN64" /D "NDEBUG" /D "_CONSOLE" /D "_LIB" /D "_UNICODE" /D "UNICODE" /Qipo /Zc:forScope /arch:AVX /Oi /MD /Fa"x64\Release\" /EHsc /nologo /Fo"x64\Release\" /Qprof-dir "x64\Release\" /Fp"x64\Release\testing.pch"

In debug mode everything goes fine. Debug mode compiler arguments:

/GS /W3 /Zc:wchar_t /Zi /Od /Fd"x64\Debug\vc120.pdb" /D "_HAS_EXCEPTIONS=0" /D "_WIN64" /D "_DEBUG" /D "_CONSOLE" /D "_LIB" /D "_UNICODE" /D "UNICODE" /Zc:forScope /RTC1 /arch:AVX /MDd /Fa"x64\Debug\" /EHsc /nologo /Fo"x64\Debug\" /Qprof-dir "x64\Debug\" /Fp"x64\Debug\testing.pch"

When inserting a print statement after the array access the issue is gone.

Thank you.

-------------------------

ASM Code:

Release:

signed char index = SCHAR_MIN;
000000013F481049  xor         eax,eax
	do {
		arr[(unsigned char)index] = (unsigned char)index;
000000013F48104B  vpshufd     xmm0,xmm0,0
000000013F481050  vpaddb      xmm5,xmm1,xmm0
000000013F481054  vpaddb      xmm8,xmm5,xmm0
000000013F481058  vpaddb      xmm11,xmm8,xmm0
	unsigned short arr[256];
	signed char index = SCHAR_MIN;
000000013F48105C  add         eax,0FFFFFF80h
	do {
		arr[(unsigned char)index] = (unsigned char)index;
000000013F48105F  vpaddb      xmm14,xmm11,xmm0
000000013F481063  vpaddb      xmm2,xmm14,xmm0
000000013F481067  vpaddb      xmm5,xmm2,xmm0
000000013F48106B  vpaddb      xmm8,xmm5,xmm0
000000013F48106F  vpaddb      xmm1,xmm8,xmm0
000000013F481073  jmp         main+50h (013F481050h)  

Release with print statement:

signed char index = SCHAR_MIN;
000000013F8D106E  mov         ebx,0FFFFFF80h
	do {
		arr[(unsigned char)index] = (unsigned char)index;
		std::cout << index << std::endl;
000000013F8D1073  mov         edx,ebx
000000013F8D1075  mov         rcx,qword ptr [__imp_std::cout (013F8DF0A0h)]
000000013F8D107C  call        std::operator<< (013F8D2B30h)
000000013F8D1081  mov         rcx,rax
000000013F8D1084  lea         rdx,[std::endl (013F8D6850h)]
000000013F8D108B  call        qword ptr [__imp_std::basic_ostream<char,std::char_traits<char> >::operator<< (013F8DF150h)]
	} while(index++ < SCHAR_MAX);
000000013F8D1091  movsx       rax,bl
000000013F8D1095  inc         ebx
000000013F8D1097  cmp         eax,7Fh
000000013F8D109A  jl          main+73h (013F8D1073h)  

Debug:

signed char index = SCHAR_MIN;
000000013FCF2B0D  mov         byte ptr [rbp],80h
	do {
		arr[(unsigned char)index] = (unsigned char)index;
000000013FCF2B11  movsx       eax,byte ptr [rbp]
000000013FCF2B15  movsx       rax,al
000000013FCF2B19  movzx       eax,al
000000013FCF2B1C  lea         rdx,[arr]
000000013FCF2B23  movsx       ecx,byte ptr [rbp]
000000013FCF2B27  movsx       rcx,cl
000000013FCF2B2B  movzx       ecx,cl
000000013FCF2B2E  imul        rcx,rcx,2
000000013FCF2B32  add         rdx,rcx
000000013FCF2B35  mov         word ptr [rdx],ax
	} while(index++ < SCHAR_MAX);
000000013FCF2B38  movsx       eax,byte ptr [rbp]
000000013FCF2B3C  movsx       rax,al
000000013FCF2B40  mov         dword ptr [rbp+4],eax
000000013FCF2B43  movsx       eax,byte ptr [rbp]
000000013FCF2B47  mov         edx,1
000000013FCF2B4C  add         eax,edx
000000013FCF2B4E  mov         byte ptr [rbp],al
000000013FCF2B51  mov         eax,dword ptr [rbp+4]
000000013FCF2B54  cmp         eax,7Fh
000000013FCF2B57  jl          main+0C9h (013FCF2B11h)