PERF: Use initializer list in ShapedImageNeighborhoodRange operator* #144
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Results in ~10% performance increase.
| @@ -347,7 +347,7 @@ class ShapedImageNeighborhoodRange final | |||
| /** Returns a reference to the current pixel. */ | |||
| reference operator*() const ITK_NOEXCEPT | |||
| { | |||
| return reference(m_ImageBufferPointer, m_ImageSize, m_OffsetTable, m_NeighborhoodAccessor, m_Location + *m_CurrentOffset); | |||
| return reference{m_ImageBufferPointer, m_ImageSize, m_OffsetTable, m_NeighborhoodAccessor, m_Location + *m_CurrentOffset}; | |||
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I'm fine with using curly braces instead of parentheses, but it only looks like a STYLE issue to me. (Actually I originally wanted to use curly braces on that line of code but KWStyle complained, at that time. If I remember correctly!) So are you sure that this change really has such an impact on the performance? If so, do you have a clue why?
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Yes, older versions of KWStyle will complain about }; 😞 , but this has been fixed in newer versions ☀️ .
I did observe the speed up, but I do not know the details of why this makes a difference to the compiler.
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Glad to hear KWStyle no longer complains about this }; syntax!
With which specific compiler version did you observe the speed-up? Because it sounds like a compiler issue to me! I just tried, but did not observe a significant performance difference between curly braces and parentheses on VS2017 (Version 15.8.9).
Anyway, the code change you're proposing here is perfectly fine to me.
Results in ~10% performance increase.
@N-Dekker this came up when testing the new constant boundary condition in ITKUltrasound.