Small fixups for n-dimensional empty tensors in CUDA non-reduction di… (#9722)

Summary:
…m ops.

Continuation of #9658.
Pull Request resolved: #9722

Differential Revision: D8956321

Pulled By: gchanan

fbshipit-source-id: 116fcaa1be5b1373f03217911556a28125cc860d

Author: gchanan

aten/src/THC/THCTensorSort.cu

@@ -9,7 +9,7 @@ void THCudaLongTensor_fillSliceWithIndex(THCState* state,
   ptrdiff_t inElements = THCudaLongTensor_nElement(state, t);
   if (inElements > 0) {
     int64_t sliceSize = THCudaLongTensor_size(state, t, dim);
-    ptrdiff_t numSlices = inElements == 0 ? 0 : inElements / sliceSize;
+    ptrdiff_t numSlices = inElements / sliceSize;
 
     dim3 grid;
     if (!THC_getGridFromTiles(numSlices, grid)) {

aten/src/THC/generic/THCTensorScatterGather.cu

@@ -209,10 +209,6 @@ void THCTensor_(scatterAdd)(THCState* state, THCTensor *tensor, int dim, THCudaL
              "Input tensor must have same dimensions as output tensor");
 
   for (int d = 0; d < THCTensor_(nDimension)(state, tensor); d++) {
-    if (d != dim) {
-      THArgCheck(THCTensor_(size)(state, tensor, d) == THCTensor_(size)(state, src, d), 4,
-                 "Input tensor must have same size as output tensor apart from the specified dimension");
-    }
     int64_t indexSizeD = THCudaLongTensor_size(state, index, d);
     if (d != dim) {
       THArgCheck(indexSizeD <= THCTensor_(size)(state, tensor, d), 3,

aten/src/THC/generic/THCTensorSort.cu

@@ -21,7 +21,6 @@ THC_API void THCTensor_(sortKeyValueInplace)(THCState* state,
   ptrdiff_t inElements = THCTensor_(nElement)(state, key);
 
   if (inElements == 0) {
-    // Zero-dim tensor; do nothing
     return;
   }