Access violation on windows with an openblas compiled with visual studio

[slegall56]

Dear xianyi,
I compiled OpenBlas with visual studio 2012 in X86
But when I call cblas_sgemm with small matrices it works but with big matrices , I got an access violation.

Below a piece of code
float* AA = (float_)malloc(270000_sizeof(float)); // matrice of 10000x27
memset(AA, 0.1, 270000_sizeof(float));
float_ BB = (float_)malloc(864_sizeof(float)); // matrice of 27x32
memset(BB, 0.2, 864_sizeof(float));
float_ CC = (float_)malloc(320000_sizeof(float)); //Matrice of 10000x32

cblas_sgemm(CblasColMajor, CblasNoTrans, CblasNoTrans, 10000, 32, 27,
1.0, AA, 10000, BB, 27, 0.0, CC, 10000);

free(AA);
free(BB);
free(CC);

This piece of code above works with openblas compiled MinGW but not with the version compile with visual studio

Any idea ?

[brada4]

can you point (using debugger) to the line in OpenBLAS code it crashes ( Assuming OpenBLAS 0.2.15)
there is nothing wrong with your BLAS call.

[slegall56]

Yes I am on OpenBlas 0.2.15
It crashes in gemm_beta.c line 62 when it tries to set c_offset1 to 0

do {
*(c_offset1 + 0) = ZERO;
*(c_offset1 + 1) = ZERO;
*(c_offset1 + 2) = ZERO;
*(c_offset1 + 3) = ZERO;
*(c_offset1 + 4) = ZERO;
*(c_offset1 + 5) = ZERO;
*(c_offset1 + 6) = ZERO;
*(c_offset1 + 7) = ZERO;
c_offset1 += 8;
i --;
} while (i > 0);

"i" start value is 89478485 and it decreases to 44739243 then it crashes

[slegall56]

I tried to compile in x64 an it works fine.
No access violation and
"i" start value is 312 and not a weird value like 89478485.

Unfortunatly I must compile in x86

[xianyi]

How do you compile OpenBLAS? By MinGW? or CMake+Visual Studio?

[slegall56]

By CMake+Visual Studio

[brada4]

Plain miscompilation. How increasing any integer can bring value down?
Just link to netlib blas and replace netlib blas dll with downloaded openbas dll (+dependencies)

[xianyi]

I can reproduce this bug now. Try to fix it.

[xianyi]

Please try the latest develop branch.

[slegall56]

Well done it works.

Thank you very much