cuda 9.0 "error: more than one operator "==" matches these operands" #797
Description
While attempting to build torch from master with cutorch with cuda 9.0.103-1 on Ubuntu 16.04 I hit an error with multiple attempts to overload the "==" and "!=" operators.
Below is an example of the error I receive.
lib/THC/CMakeFiles/THC.dir/build.make:4243: recipe for target 'lib/THC/CMakeFiles/THC.dir/THC_generated_THCTensorMathPairwise.cu.o' failed
make[2]: *** [lib/THC/CMakeFiles/THC.dir/THC_generated_THCTensorMathPairwise.cu.o] Error 1
/pkgbuild/torch/torch/extra/cutorch/lib/THC/generic/THCTensorMath.cu(393): error: more than one operator "==" matches these operands:
function "operator==(const __half &, const __half &)"
function "operator==(half, half)"
operand types are: half == half
/pkgbuild/torch/torch/extra/cutorch/lib/THC/generic/THCTensorMath.cu(414): error: more than one operator "==" matches these operands:
function "operator==(const __half &, const __half &)"
function "operator==(half, half)"
operand types are: half == half
I was able to track down the two operator overloads.
One is in
https://github.com/torch/cutorch/blob/master/lib/THC/THCTensorTypeUtils.cuh#L176
And the other is in
/usr/local/cuda-9.0/targets/ppc64le-linux/include/cuda_fp16.hpp
The operator in cuda_fp16.hpp was provided by the cuda package, but only covers the __device__ and not the __host__. So we still need to overload the "==" for halfs in the __host__, however, the code currently in cutorch fails on compile time.
It looks like @csarofeen worked on the initial port to cuda9.0 for cutorch. I'm not sure if he can provide some help on what's going on here?
Is there any additional information you need from me? Thanks in advance!!