[WebAssembly] Refactor load ISel tablegen patterns into classes

Not all of these will be able to be used by atomics because tablegen, but it
still seems like a good change by itself.

Differential Revision: https://reviews.llvm.org/D37345

llvm-svn: 312287

llvm/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td

@@ -18,16 +18,17 @@
 
 let Defs = [ARGUMENTS] in {
 // TODO: add the rest of the atomic loads
-// TODO: factor out 0xfe atomic prefix?
-def ATOMIC_LOAD_I32 : ATOMIC_I<(outs I32:$dst),
-                        (ins P2Align:$p2align, offset32_op:$off, I32:$addr),
-                        [], "i32.atomic.load\t$dst, ${off}(${addr})${p2align}",
-                        0xfe10>;
+def ATOMIC_LOAD_I32 : CLoadI32<"i32.atomic.load", 0xfe10>;
+def ATOMIC_LOAD_I64 : CLoadI64<"i64.atomic.load", 0xfe11>;
 } // Defs = [ARGUMENTS]
 
 // Select loads with no constant offset.
 let Predicates = [HasAtomics] in {
-def : Pat<(i32 (atomic_load I32:$addr)), (ATOMIC_LOAD_I32 0, 0, $addr)>;
+class ALoadPatNoOffset<ValueType ty, SDNode node, I inst> :
+  Pat<(ty (node I32:$addr)), (inst 0, 0, $addr)>;
+def : ALoadPatNoOffset<i32, atomic_load, ATOMIC_LOAD_I32>;
+def : ALoadPatNoOffset<i64, atomic_load, ATOMIC_LOAD_I64>;
+
 }
 
 //===----------------------------------------------------------------------===//