[BE] Fix signed-unsigned warnings (pytorch#48848)

Summary:
Switch to range loops when possible
Replace `ptrdiff_t`(signed type) with `size_t`(unsigned type)

Pull Request resolved: pytorch#48848

Reviewed By: walterddr

Differential Revision: D25338250

Pulled By: malfet

fbshipit-source-id: e840618b113b8bc0d8bb067c2fdf06e3ec9233d4

aten/src/ATen/BatchingRegistrations.cpp

@@ -941,8 +941,8 @@ Tensor new_empty_strided_batching_rule(
         size.size(), ") must match dimensionality of strides (",
         stride.size(), ")");
   auto storage_size = native::storage_size_for(size, stride);
-  for (int64_t idx = 0; idx < physical_strides.size(); ++idx) {
-    physical_strides[idx] *= storage_size;
+  for (auto& physical_stride : physical_strides) {
+    physical_stride *= storage_size;
   }
 
   // physical_strides = [B1 * B2 * S, B2 * S, S] + strides

aten/src/ATen/NamedTensorUtils.cpp

@@ -264,11 +264,11 @@ static std::vector<Dimname> compute_dot_product_outnames(
   }
   std::vector<Dimname> outnames(num_outnames, Dimname::wildcard());
   int64_t index = 0;
-  for (int64_t j = 0; j < tensor_names.size(); ++j) {
+  for (size_t j = 0; j < tensor_names.size(); ++j) {
     if (j == tensor_dotted_dim) continue;
     outnames[index++] = tensor_names[j];
   }
-  for (int64_t j = 0; j < other_names.size(); ++j) {
+  for (size_t j = 0; j < other_names.size(); ++j) {
     if (j == other_dotted_dim) continue;
     outnames[index++] = other_names[j];
   }

aten/src/ATen/TensorIterator.cpp

@@ -939,8 +939,8 @@ TensorIterator TensorIterator::reduce_op(Tensor& out1, Tensor& out2, const Tenso
 }
 
 void TensorIteratorBase::populate_operands(TensorIteratorConfig& config) {
-  for (int i = 0; i < config.tensors_.size(); i++) {
-    operands_.emplace_back(std::move(config.tensors_[i]));
+  for (auto& tensor: config.tensors_) {
+    operands_.emplace_back(std::move(tensor));
   }
   num_outputs_ = config.num_outputs_;
 }

aten/src/ATen/TensorNames.cpp

@@ -61,10 +61,10 @@ TensorNames::TensorNames(ArrayRef<Dimname> names, int64_t start, int64_t end) {
 }
 
 TensorNames& TensorNames::unifyFromRightInplace(const TensorNames& other, const char* op_name) {
-  int64_t size_diff = std::labs(names_.size() - other.names_.size());
+  size_t size_diff = std::labs(names_.size() - other.names_.size());
 
   if (names_.size() > other.names_.size()) {
-    for (int64_t idx = size_diff; idx < names_.size(); ++idx) {
+    for (size_t idx = size_diff; idx < names_.size(); ++idx) {
       names_[idx] = names_[idx].unify(other.names_[idx - size_diff], op_name);
     }
   } else {

aten/src/ATen/native/Convolution.cpp

@@ -177,13 +177,13 @@ auto ConvParams::needs_64bit_indexing_no_split(const at::Tensor& input, const at
   int64_t outsize = 1;
   if (transposed) {
     std::vector<int64_t> o = conv_input_size(input.sizes(), weight.sizes(), padding, output_padding, stride, dilation, groups);
-    for (int64_t i = 1; i < o.size(); i++) {
-      outsize *= o[i];
+    for (const auto& e: o) {
+      outsize *= e;
     }
   } else {
     std::vector<int64_t> o = conv_output_size(input.sizes(), weight.sizes(), padding, stride, dilation);
-    for (int64_t i = 1; i < o.size(); i++) {
-      outsize *= o[i];
+    for (const auto& e: o) {
+      outsize *= e;
     }
   }
   return outsize > int_max;

aten/src/ATen/native/ForeachOpsKernels.cpp

@@ -201,7 +201,7 @@ std::vector<Tensor> foreach_tensor_##NAME##_slow(TensorList tensors1, TensorList
                                                                                              \
   std::vector<Tensor> result;                                                                \
   result.reserve(tensors1.size());                                                           \
-  for (int i = 0; i < tensors1.size(); i++) {                                                \
+  for (size_t i = 0; i < tensors1.size(); i++) {                                             \
     result.emplace_back(at::NAME(tensors1[i], tensors2[i]));                                 \
   }                                                                                          \
                                                                                              \

aten/src/TH/generic/THStorage.cpp

@@ -115,10 +115,9 @@ void THStorage_(resizeBytes)(THStorage* storage, ptrdiff_t size_bytes) {
 
 void THStorage_(fill)(THStorage *storage, scalar_t value)
 {
-  ptrdiff_t i;
   auto type_meta = caffe2::TypeMeta::Make<scalar_t>();
   size_t numel = storage->nbytes() / type_meta.itemsize();
-  for (i = 0; i < numel; i++)
+  for (size_t i = 0; i < numel; i++)
     THStorage_(data)(storage)[i] = value;
 }
 

aten/src/TH/generic/THStorageCopy.cpp

@@ -8,7 +8,7 @@ void THStorage_(copy)(THStorage *storage, THStorage *src)
   scalar_t *scalar_src = THStorage_(data)(src);
   scalar_t *data = THStorage_(data)(storage);
   uint64_t numel = storage->nbytes() / sizeof(scalar_t);
-  for (ptrdiff_t i = 0; i < numel; ++i) {
+  for (uint64_t i = 0; i < numel; ++i) {
     data[i] = scalar_src[i];
   }
 }
@@ -19,11 +19,10 @@ void THStorage_(copy)(THStorage *storage, THStorage *src)
 #define IMPLEMENT_THStorage_COPY(TYPENAMESRC)                \
   void THStorage_(copy##TYPENAMESRC)(                        \
       THStorage * storage, TH##TYPENAMESRC##Storage * src) { \
-    ptrdiff_t i;                                             \
     auto data = THStorage_(data)(storage);                   \
     auto src_data = TH##TYPENAMESRC##Storage_data(src);      \
     uint64_t numel = storage->nbytes() / sizeof(scalar_t);   \
-    for (i = 0; i < numel; i++)                              \
+    for (uint64_t i = 0; i < numel; i++)                     \
       data[i] = static_cast<scalar_t>(src_data[i]);          \
   }
 

caffe2/serialize/crc_alt.h

@@ -680,12 +680,12 @@ uint32_t crc32_combine(uint32_t crcA, uint32_t crcB, size_t lengthB)
 
   // put operator for one zero bit in odd
   odd[0] = Polynomial;    // CRC-32 polynomial
-  for (int i = 1; i < CrcBits; i++)
+  for (uint32_t i = 1; i < CrcBits; i++)
     odd[i] = 1 << (i - 1);
 
   // put operator for two zero bits in even
   // same as gf2_matrix_square(even, odd);
-  for (int i = 0; i < CrcBits; i++)
+  for (uint32_t i = 0; i < CrcBits; i++)
   {
     uint32_t vec = odd[i];
     even[i] = 0;
@@ -695,7 +695,7 @@ uint32_t crc32_combine(uint32_t crcA, uint32_t crcB, size_t lengthB)
   }
   // put operator for four zero bits in odd
   // same as gf2_matrix_square(odd, even);
-  for (int i = 0; i < CrcBits; i++)
+  for (uint32_t i = 0; i < CrcBits; i++)
   {
     uint32_t vec = even[i];
     odd[i] = 0;
@@ -711,7 +711,7 @@ uint32_t crc32_combine(uint32_t crcA, uint32_t crcB, size_t lengthB)
   for (; lengthB > 0; lengthB >>= 1)
   {
     // same as gf2_matrix_square(a, b);
-    for (int i = 0; i < CrcBits; i++)
+    for (uint32_t i = 0; i < CrcBits; i++)
     {
       uint32_t vec = b[i];
       a[i] = 0;