From 68b4e6dd18e368e1f78c6a5bea76417c35f72196 Mon Sep 17 00:00:00 2001
From: =?utf8?q?=EB=B0=95=EC=A2=85=ED=98=84/=EB=8F=99=EC=9E=91=EC=A0=9C?=
 =?utf8?q?=EC=96=B4Lab=28SR=29/Staff=20Engineer/=EC=82=BC=EC=84=B1?=
 =?utf8?q?=EC=A0=84=EC=9E=90?= <jh1302.park@samsung.com>
Date: Thu, 6 Sep 2018 19:40:56 +0900
Subject: [PATCH] [enco] Implement AvgPool2D decomposition (#1388)

With this commit, enco backend now decomposes Static AvgPool2D with
padding into PadF and PaddingExcluded AvgPool2D without padding.

Signed-off-by: Jonghyun Park <jh1302.park@samsung.com>
---
 contrib/enco/core/src/Transforms/Rewrite.cpp | 81 ++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/contrib/enco/core/src/Transforms/Rewrite.cpp b/contrib/enco/core/src/Transforms/Rewrite.cpp
index ec01ad1..69383d2 100644
--- a/contrib/enco/core/src/Transforms/Rewrite.cpp
+++ b/contrib/enco/core/src/Transforms/Rewrite.cpp
@@ -1,7 +1,13 @@
 #include "Rewrite.h"
 
+#include <nncc/core/ADT/feature/Shape.h>
+#include <nncc/core/ADT/feature/HWCLayout.h>
+
 #include <cassert>
 
+using namespace nncc::core::ADT;
+using nncc::core::ADT::feature::num_elements;
+
 namespace
 {
 
@@ -12,6 +18,40 @@ bool empty(coco::Padding2D *pad)
 
 } // namespace
 
+namespace
+{
+namespace ShapeTransform
+{
+
+class Pad
+{
+public:
+  Pad(const coco::Padding2D *pad) : _pad{pad}
+  {
+    // DO NOTHING
+  }
+
+public:
+  // @brief Return the expected OFM shape for a given IFM shape
+  feature::Shape forward(const feature::Shape &ifm_shape) const
+  {
+    const uint32_t OFM_C = ifm_shape.depth();
+    const uint32_t OFM_H = ifm_shape.height() + _pad->top() + _pad->bottom();
+    const uint32_t OFM_W = ifm_shape.width() + _pad->left() + _pad->right();
+
+    return feature::Shape{OFM_C, OFM_H, OFM_W};
+  }
+
+private:
+  const coco::Padding2D *_pad;
+};
+
+} // namespace ShapeTransform
+
+ShapeTransform::Pad shape_xform(const coco::Padding2D *pad) { return ShapeTransform::Pad{pad}; }
+
+} // namespace
+
 namespace enco
 {
 
@@ -33,6 +73,47 @@ void AvgPoolRewritePass::runOnModule(coco::Module *m) const
               // NOTE If there is no padding, Static and PaddingExcluded schemes are equivalent
               avgpool->divisor(coco::AvgPool2D::Divisor::PaddingExcluded);
             }
+            else
+            {
+              // Before: Static AvgPool2D with Padding
+              // After: PadF; PaddingExcluded AvgPool2D without Padding
+
+              // Create PadF
+              auto ifm_obj = unit->ifm();
+              assert(ifm_obj != nullptr);
+
+              auto pad_shape = shape_xform(avgpool->pad()).forward(ifm_obj->shape());
+              auto pad_bag = m->entity()->bag()->create(num_elements(pad_shape));
+              auto pad_obj = m->entity()->object()->create(pad_shape);
+
+              pad_obj->bag(pad_bag);
+              pad_obj->reorder<feature::HWCLayout>();
+
+              auto pad_op = m->entity()->op()->create<coco::PadF>();
+
+              pad_op->pad()->top(avgpool->pad()->top());
+              pad_op->pad()->bottom(avgpool->pad()->bottom());
+              pad_op->pad()->left(avgpool->pad()->left());
+              pad_op->pad()->right(avgpool->pad()->right());
+
+              auto pad_instr = m->entity()->instr()->create<coco::UnitF>();
+
+              pad_instr->ifm(ifm_obj);
+              pad_instr->ofm(pad_obj);
+              pad_instr->op(pad_op);
+
+              // Insert PadF before AvgPool2D
+              pad_instr->insertBefore(unit);
+
+              // Rewrite AvgPool2D as PaddingExcluded AvgPool2D without Padding
+              unit->ifm(pad_obj);
+
+              avgpool->divisor(coco::AvgPool2D::Divisor::PaddingExcluded);
+              avgpool->pad()->top(0);
+              avgpool->pad()->bottom(0);
+              avgpool->pad()->left(0);
+              avgpool->pad()->right(0);
+            }
           }
         }
       }
-- 
2.7.4