Prototype prefetch instructions (#3467)

As proposed in https://github.com/WebAssembly/simd/pull/352, using the opcodes
used in the LLVM and V8 implementations.

1 files changed, 21 insertions, 0 deletions

diff --git a/src/wasm/wasm-binary.cpp b/src/wasm/wasm-binary.cpp
index e616493af..f3160c461 100644
--- a/src/wasm/wasm-binary.cpp
+++ b/src/wasm/wasm-binary.cpp
@@ -2967,6 +2967,9 @@ BinaryConsts::ASTNodes WasmBinaryBuilder::readExpression(Expression*& curr) {
       if (maybeVisitSIMDLoadStoreLane(curr, opcode)) {
         break;
       }
+      if (maybeVisitPrefetch(curr, opcode)) {
+        break;
+      }
       throwError("invalid code after SIMD prefix: " + std::to_string(opcode));
       break;
     }
@@ -5372,6 +5375,24 @@ bool WasmBinaryBuilder::maybeVisitSIMDLoadStoreLane(Expression*& out,
   return true;
 }
 
+bool WasmBinaryBuilder::maybeVisitPrefetch(Expression*& out, uint32_t code) {
+  PrefetchOp op;
+  switch (code) {
+    case BinaryConsts::PrefetchT:
+      op = PrefetchTemporal;
+      break;
+    case BinaryConsts::PrefetchNT:
+      op = PrefetchNontemporal;
+      break;
+    default:
+      return false;
+  }
+  Address align, offset;
+  readMemoryAccess(align, offset);
+  out = Builder(wasm).makePrefetch(op, offset, align, popNonVoidExpression());
+  return true;
+}
+
 void WasmBinaryBuilder::visitSelect(Select* curr, uint8_t code) {
   BYN_TRACE("zz node: Select, code " << int32_t(code) << std::endl);
   if (code == BinaryConsts::SelectWithType) {