[GitHub] piiswrong closed pull request #8472: Fix arange bug on ARM

[GitBox <gi...@apache.org>]

piiswrong closed pull request #8472: Fix arange bug on ARM
URL: https://github.com/apache/incubator-mxnet/pull/8472
 
 
   

This is a PR merged from a forked repository.
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As this is a foreign pull request (from a fork), the diff is supplied
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diff --git a/src/operator/tensor/init_op.h b/src/operator/tensor/init_op.h
index b2bd15ceec..bb6d3c129f 100644
--- a/src/operator/tensor/init_op.h
+++ b/src/operator/tensor/init_op.h
@@ -378,9 +378,17 @@ void RangeCompute(const nnvm::NodeAttrs& attrs,
   Stream<xpu> *s = ctx.get_stream<xpu>();
   const RangeParam& param = nnvm::get<RangeParam>(attrs.parsed);
   MSHADOW_TYPE_SWITCH(outputs[0].type_flag_, DType, {
-    Kernel<range_fwd, xpu>::Launch(s, outputs[0].Size(),
-        static_cast<int>(param.repeat), static_cast<DType>(param.start),
-        static_cast<DType>(param.step), req[0], outputs[0].dptr<DType>());
+      // Force unsigned params to take two's complement form on ARM to ensure consistency with x86
+      // results.  Casting negative floats to unsigned types is undefined in the CPP standard.
+      auto step = std::is_signed<DType>() ? param.step : static_cast<int>(param.step);
+      auto start = std::is_signed<DType>() ? param.start : static_cast<int>(param.start);
+      Kernel<range_fwd, xpu>::Launch(s,
+                                     outputs[0].Size(),
+                                     static_cast<int>(param.repeat),
+                                     static_cast<DType>(start),
+                                     static_cast<DType>(step),
+                                     req[0],
+                                     outputs[0].dptr<DType>());
   });
 }
 
diff --git a/tests/python/unittest/test_operator.py b/tests/python/unittest/test_operator.py
index 5fd2cdc53c..1ad10c8abe 100644
--- a/tests/python/unittest/test_operator.py
+++ b/tests/python/unittest/test_operator.py
@@ -2555,6 +2555,7 @@ def test_arange():
                        (0, 10),
                        (5, 100, 4),
                        (50, -50, -2),
+                       (-100, 100, 1),
                        (1.3, 456.6, 1.3)]
         for dtype in dtype_list:
             for config in config_list:


 

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