[WASM SIMD] Implement horizontal add for float and integer types.

test/cctest/test-disasm-arm.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 1026 matching lines @@
       COMPARE(vmin(q15, q0, q8),
               "f260ef60       vmin.f32 q15, q0, q8");
       COMPARE(vmax(q15, q0, q8),
               "f240ef60       vmax.f32 q15, q0, q8");
       COMPARE(vmax(NeonS8, q0, q1, q2),
               "f2020644       vmax.s8 q0, q1, q2");
       COMPARE(vmin(NeonU16, q1, q2, q8),
               "f3142670       vmin.u16 q1, q2, q8");
       COMPARE(vmax(NeonS32, q15, q0, q8),
               "f260e660       vmax.s32 q15, q0, q8");
+      COMPARE(vpadd(d0, d1, d2),
+              "f3010d02       vpadd.f32 d0, d1, d2");
+      COMPARE(vpadd(Neon8, d0, d1, d2),
+              "f2010b12       vpadd.i8 d0, d1, d2");
+      COMPARE(vpadd(Neon16, d0, d1, d2),
+              "f2110b12       vpadd.i16 d0, d1, d2");
+      COMPARE(vpadd(Neon32, d0, d1, d2),
+              "f2210b12       vpadd.i32 d0, d1, d2");
       COMPARE(vpmax(NeonS8, d0, d1, d2),
               "f2010a02       vpmax.s8 d0, d1, d2");
       COMPARE(vpmin(NeonU16, d1, d2, d8),
               "f3121a18       vpmin.u16 d1, d2, d8");
       COMPARE(vpmax(NeonS32, d15, d0, d8),
               "f220fa08       vpmax.s32 d15, d0, d8");
       COMPARE(vadd(q15, q0, q8),
               "f240ed60       vadd.f32 q15, q0, q8");
       COMPARE(vadd(Neon8, q0, q1, q2),
               "f2020844       vadd.i8 q0, q1, q2");
@@ skipping 398 matching lines @@
 
   COMPARE(ldrexb(r0, r1), "e1d10f9f       ldrexb r0, [r1]");
   COMPARE(strexb(r0, r1, r2), "e1c20f91       strexb r0, r1, [r2]");
   COMPARE(ldrexh(r0, r1), "e1f10f9f       ldrexh r0, [r1]");
   COMPARE(strexh(r0, r1, r2), "e1e20f91       strexh r0, r1, [r2]");
   COMPARE(ldrex(r0, r1), "e1910f9f       ldrex r0, [r1]");
   COMPARE(strex(r0, r1, r2), "e1820f91       strex r0, r1, [r2]");
 
   VERIFY_RUN();
 }