Hi, Olaf. Thank you for your reply!

I change the type of "i" into "int" and even add the "#pragma ivdep", but it seems no help to the auto-vectorization of "short" type.

However, when I change the type of "min_val" into "int"and keep the "i"'s type be "short", the auto-vectorization works.

So my question is why theICC11.1 cannot use the PCMPGTWto vectorize the "short" loop, as it using the PCMPGTD to vectorize the "int" loop?

Test Code: the first two loops cannot be auto-vectorzied due to the "short" type of "min_val".

//test_min_s16_s16_s32
	int i = 0;
	short s16_src[2048];
	short min_val = 0;

	for(i=0;i<2048;i++)//existence of vector dependence.
	{
		if(min_val > s16_src[i])
		{
			min_val = s16_src[i];
		}
	}
//test_min_u8_s16_s32
	int i = 0;
	unsigned char u8_src[2048];
	short min_val = 0;

	for(i=0;i<2048;i++)//existence of vector dependence
	{
		if(min_val > u8_src[i])
		{
			min_val = u8_src[i];
		}
	}
//test_min_s16_s32_s32
	int i = 0; //"short" type also works
	short s16_src[2048];
	int min_val = 0;
		
	for(i=0;i<2048;i++)//LOOP WAS VECTORIZED.
	{
		if(min_val > s16_src[i])
		{
			min_val = s16_src[i];
		}
	}
//test_min_u8_s32_s32
	int i = 0; //"short" type also works
	unsigned char u8_src[2048];
	int min_val = 0;

	for(i=0;i<2048;i++)//LOOP WAS VECTORIZED.
	{
		if(min_val > u8_src[i])
		{
			min_val = u8_src[i];
		}
	}

Hi, Mark

I am using the Intel C++ Compiler 11.1.038 on the Windows XP(SP3), the CPU is Core i5 M450.
Can you reproduce my problem?

Thanks,
lychee