Revert "[WebAssembly] Split and recombine multivalue calls for ISel"

Summary:
This reverts commit 28857d14a86b1e99a9d2795636a5faf17674f5a2. This
commit worked toward a solution that did not turn out to be feasible
because MachineInstrs cannot contain an arbitrary number of defs.

Reviewers: aheejin

Subscribers: dschuff, sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73927
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
index 04a9089..417b6b5 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -411,29 +411,6 @@
   return DoneMBB;
 }
 
-static MachineBasicBlock *LowerCallResults(MachineInstr &CallResults,
-                                           DebugLoc DL, MachineBasicBlock *BB,
-                                           const TargetInstrInfo &TII) {
-  MachineInstr &CallParams = *CallResults.getPrevNode();
-  assert(CallParams.getOpcode() == WebAssembly::CALL_PARAMS);
-  assert(CallResults.getOpcode() == WebAssembly::CALL_RESULTS);
-
-  MachineFunction &MF = *BB->getParent();
-  const MCInstrDesc &MCID = TII.get(WebAssembly::CALL);
-  MachineInstrBuilder MIB(MF, MF.CreateMachineInstr(MCID, DL));
-
-  for (auto Def : CallResults.defs())
-    MIB.add(Def);
-  for (auto Use : CallParams.uses())
-    MIB.add(Use);
-
-  BB->insert(CallResults.getIterator(), MIB);
-  CallParams.eraseFromParent();
-  CallResults.eraseFromParent();
-
-  return BB;
-}
-
 MachineBasicBlock *WebAssemblyTargetLowering::EmitInstrWithCustomInserter(
     MachineInstr &MI, MachineBasicBlock *BB) const {
   const TargetInstrInfo &TII = *Subtarget->getInstrInfo();
@@ -466,8 +443,7 @@
   case WebAssembly::FP_TO_UINT_I64_F64:
     return LowerFPToInt(MI, DL, BB, TII, true, true, true,
                         WebAssembly::I64_TRUNC_U_F64);
-  case WebAssembly::CALL_RESULTS:
-    return LowerCallResults(MI, DL, BB, TII);
+    llvm_unreachable("Unexpected instruction to emit with custom inserter");
   }
 }