f32x4.add_pairwise and f64x2.add_pairwise

proposals/simd/BinarySIMD.md

@@ -222,3 +222,5 @@ For example, `ImmLaneIdx16` is a byte with values in the range 0-15 (inclusive).
 | `i32x4.trunc_sat_f32x4_u`  |    `0xf9`| -                  |
 | `f32x4.convert_i32x4_s`    |    `0xfa`| -                  |
 | `f32x4.convert_i32x4_u`    |    `0xfb`| -                  |
+| `f32x4.add_pairwise`       |    `0xfe`| -                  |
+| `f64x2.add_pairwise`       |    `0xff`| -                  |

proposals/simd/ImplementationStatus.md

@@ -190,6 +190,8 @@
 | `i32x4.trunc_sat_f32x4_u`  |               `-msimd128` | :heavy_check_mark: |                    |                    | :heavy_check_mark: |
 | `f32x4.convert_i32x4_s`    |               `-msimd128` | :heavy_check_mark: |                    |                    | :heavy_check_mark: |
 | `f32x4.convert_i32x4_u`    |               `-msimd128` | :heavy_check_mark: |                    |                    | :heavy_check_mark: |
+| `f32x4.add_pairwise`       |                           |                    |                    |                    |                    |
+| `f64x2.add_pairwise`       |                           |                    |                    |                    |                    |
 
 [1] Tip of tree LLVM as of May 20, 2020
 

proposals/simd/SIMD.md

@@ -938,6 +938,14 @@ Lane-wise rounding to the nearest integral value with the magnitude not larger t
 
 Lane-wise rounding to the nearest integral value; if two values are equally near, rounds to the even one.
 
+## Pairwise Arithmetics
+
+### Addition
+* `f32x4.add_pairwise(a: v128, b: v128) -> v128`
+* `f64x2.add_pairwise(a: v128, b: v128) -> v128`
+
+IEEE `addition` of pairs of elements in concantation of `a` and `b` vectors.
+
 ## Conversions
 ### Integer to floating point
 * `f32x4.convert_i32x4_s(a: v128) -> v128`