stage2: implement `@prefetch`

This reverts commit f423b5949b8722d4b290f57c3d06d015e39217b0,
re-instating commit d48e4245b68bf25c7f41804a5012ac157a5ee546.

1 files changed, 6 insertions, 0 deletions

diff --git a/src/arch/aarch64/CodeGen.zig b/src/arch/aarch64/CodeGen.zig
index f8a774af3b..d5993ea5d7 100644
--- a/src/arch/aarch64/CodeGen.zig
+++ b/src/arch/aarch64/CodeGen.zig
@@ -595,6 +595,7 @@ fn genBody(self: *Self, body: []const Air.Inst.Index) InnerError!void {
             .error_name      => try self.airErrorName(inst),
             .splat           => try self.airSplat(inst),
             .vector_init     => try self.airVectorInit(inst),
+            .prefetch        => try self.airPrefetch(inst),
 
             .atomic_store_unordered => try self.airAtomicStore(inst, .Unordered),
             .atomic_store_monotonic => try self.airAtomicStore(inst, .Monotonic),
@@ -2597,6 +2598,11 @@ fn airVectorInit(self: *Self, inst: Air.Inst.Index) !void {
     return bt.finishAir(result);
 }
 
+fn airPrefetch(self: *Self, inst: Air.Inst.Index) !void {
+    const prefetch = self.air.instructions.items(.data)[inst].prefetch;
+    return self.finishAir(inst, MCValue.dead, .{ prefetch.ptr, .none, .none });
+}
+
 fn resolveInst(self: *Self, inst: Air.Inst.Ref) InnerError!MCValue {
     // First section of indexes correspond to a set number of constant values.
     const ref_int = @enumToInt(inst);