[Simd] Add extending pairwise adds to interpreter (#4022)

3 files changed, 33 insertions, 4 deletions

diff --git a/src/literal.h b/src/literal.h
index 28e6f03cf..3d4562f77 100644
--- a/src/literal.h
+++ b/src/literal.h
@@ -612,6 +612,10 @@ public:
   Literal floorF64x2() const;
   Literal truncF64x2() const;
   Literal nearestF64x2() const;
+  Literal extAddPairwiseToSI16x8() const;
+  Literal extAddPairwiseToUI16x8() const;
+  Literal extAddPairwiseToSI32x4() const;
+  Literal extAddPairwiseToUI32x4() const;
   Literal truncSatToSI32x4() const;
   Literal truncSatToUI32x4() const;
   Literal convertSToF32x4() const;
diff --git a/src/wasm-interpreter.h b/src/wasm-interpreter.h
index 872d90603..13a3f2876 100644
--- a/src/wasm-interpreter.h
+++ b/src/wasm-interpreter.h
@@ -530,13 +530,13 @@ public:
       case NearestVecF64x2:
         return value.nearestF64x2();
       case ExtAddPairwiseSVecI8x16ToI16x8:
-        WASM_UNREACHABLE("unimp");
+        return value.extAddPairwiseToSI16x8();
       case ExtAddPairwiseUVecI8x16ToI16x8:
-        WASM_UNREACHABLE("unimp");
+        return value.extAddPairwiseToUI16x8();
       case ExtAddPairwiseSVecI16x8ToI32x4:
-        WASM_UNREACHABLE("unimp");
+        return value.extAddPairwiseToSI32x4();
       case ExtAddPairwiseUVecI16x8ToI32x4:
-        WASM_UNREACHABLE("unimp");
+        return value.extAddPairwiseToUI32x4();
       case TruncSatSVecF32x4ToVecI32x4:
         return value.truncSatToSI32x4();
       case TruncSatUVecF32x4ToVecI32x4:
diff --git a/src/wasm/literal.cpp b/src/wasm/literal.cpp
index 7e36097c2..9b2171a74 100644
--- a/src/wasm/literal.cpp
+++ b/src/wasm/literal.cpp
@@ -1809,6 +1809,31 @@ Literal Literal::truncF64x2() const {
 Literal Literal::nearestF64x2() const {
   return unary<2, &Literal::getLanesF64x2, &Literal::nearbyint>(*this);
 }
+
+template<int Lanes, typename LaneFrom, typename LaneTo>
+static Literal extAddPairwise(const Literal& vec) {
+  LaneArray<Lanes* 2> lanes = getLanes<LaneFrom, Lanes * 2>(vec);
+  LaneArray<Lanes> result;
+  for (size_t i = 0; i < Lanes; i++) {
+    result[i] = Literal((LaneTo)(LaneFrom)lanes[i * 2 + 0].geti32() +
+                        (LaneTo)(LaneFrom)lanes[i * 2 + 1].geti32());
+  }
+  return Literal(result);
+}
+
+Literal Literal::extAddPairwiseToSI16x8() const {
+  return extAddPairwise<8, int8_t, int16_t>(*this);
+}
+Literal Literal::extAddPairwiseToUI16x8() const {
+  return extAddPairwise<8, uint8_t, int16_t>(*this);
+}
+Literal Literal::extAddPairwiseToSI32x4() const {
+  return extAddPairwise<4, int16_t, int32_t>(*this);
+}
+Literal Literal::extAddPairwiseToUI32x4() const {
+  return extAddPairwise<4, uint16_t, uint32_t>(*this);
+}
+
 Literal Literal::truncSatToSI32x4() const {
   return unary<4, &Literal::getLanesF32x4, &Literal::truncSatToSI32>(*this);
 }