[WebAssembly] Use named operands to identify loads and stores

[tlively]

Summary

Uses the named operands tablegen feature to look up the indices of
offset, address, and p2align operands for all load and store
instructions. This replaces brittle, incorrect logic for identifying
loads and store when eliminating frame indices, which previously
crashed on bulk-memory ops. It also cleans up the SetP2Alignment pass.

[tlively]

• Fix SIMD, restore SIMD tests

[aheejin]

Nice! I'm learning more tablegen stuff everytime I see your CL 👍I have a few questions:

llvm/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp

74 ↗

(On Diff #189434)

Nit: how about making it a variable as you did for OffsetOperandNum below, like

unsigned AddrOperandNum = WebAssembly::getNamedOperandIdx(
          MI.getOpcode(), WebAssembly::OpName::addr));
if (AddrOperandNum == FIOperandNum) {
  ...

86 ↗

(On Diff #189434)

While this is a lot more general and better than the previous code and the fix looks correct, I can't find any bulk memory instructions in its td file that has addr operands. I don't think the bulk memory test cases enter this if block. Is that intended?

llvm/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp

94 ↗

(On Diff #189434)

Why not changed? I see the previous code didn't even touch Changed, but aren't we supposed set it to true when if (P2AlignOpNum != -1) holds?

llvm/test/CodeGen/WebAssembly/bulk-memory.ll

147 ↗

(On Diff #189434)

• This sentence sounds like __stack_pointer global itself is bumped to a new location, which actually happens in non-leaf functions. But here we only read it to compute the frame index and don't modify __stack_pointer itself..?
• "in non-leaf function it must be 16-byte aligned, and there is no special case for leaf functions.": Why is it 16 bytes aligned and why is there no special case for leaf functions?

[tlively]

• Address comments

[tlively]

llvm/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp

74 ↗

(On Diff #189434)

Good idea, will do.

86 ↗

(On Diff #189434)

Very much intended! The previous errors were due to bulk memory operations were entering this block, which tried to extract Offset operands that did not exist. Now they do not enter this block, which fixes the error.

llvm/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp

94 ↗

(On Diff #189434)

I had this question too, but I did not know the full context of what this return value means and how it is used, so I wanted to be conservative and not change the behavior of the code. It looks like setting Changed to true if we call rewriteP2Align doesn't break anything, so we can go with that.

llvm/test/CodeGen/WebAssembly/bulk-memory.ll

147 ↗

(On Diff #189434)

Updated to reflect my findings from investigating TransientStackAlignment.

[aheejin]

LGTM w/ a comment question.

llvm/test/CodeGen/WebAssembly/bulk-memory.ll

147 ↗

(On Diff #189434)

The comment still says "stack_pointer is bumped". What I meant was __stack_pointer is NOT bumped, i.e., there's no global.set __stack_pointer in the generated code. Isn't __stack_pointer here just used to compute the frame index?

[dschuff]

llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp

30 ↗

(On Diff #189649)

do you need to #undef GET_INSTRINFO_CTOR_DTOR before you include the .inc file again?
edit: also above.

[tlively]

llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp

30 ↗

(On Diff #189649)

No, the undef is taken care of inside the included file. This is a common pattern for including all TableGen files.

llvm/test/CodeGen/WebAssembly/bulk-memory.ll

147 ↗

(On Diff #189434)

There are two "stack pointers" in play here. The stack pointer that gets bumped is LLVM's idea of a stack pointer, which is subject to StackAlignment and TransientStackAlignment and is used as the base address for the offsets of locals. The global __stack_pointer that participates in the WebAssembly ABI does not get bumped because we're using the red zone, but that is an invention of the WebAssembly backend that the rest of LLVM is not aware of.

I guess I can make this less confusing by saying "The stack pointer is bumped" instead of "__stack_pointer is bumped". Does that seem reasonable to you?

[aheejin]

llvm/test/CodeGen/WebAssembly/bulk-memory.ll

147 ↗

(On Diff #189434)

Yeah that sounds clearer.

llvm/trunk/lib/Target/WebAssembly/MCTargetDesc/WebAssemblyMCTargetDesc.h

inline unsigned GetDefaultP2Align(unsigned Opcode) {
   case WebAssembly::STORE_v2f64:
   case WebAssembly::STORE_v2f64_S:
     return 4;
   default:
     llvm_unreachable("Only loads and stores have p2align values");
   }
 }
 
-/// The operand number of the load or store address in load/store instructions.
-static const unsigned LoadAddressOperandNo = 3;
-static const unsigned StoreAddressOperandNo = 2;
-
-/// The operand number of the load or store p2align in load/store instructions.
-static const unsigned LoadP2AlignOperandNo = 1;
-static const unsigned StoreP2AlignOperandNo = 0;
-
 /// This is used to indicate block signatures.
 enum class ExprType : unsigned {
   Void = 0x40,
   I32 = 0x7F,
   I64 = 0x7E,
   F32 = 0x7D,
   F64 = 0x7C,
   V128 = 0x7B,

llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrAtomics.td

 // WebAssemblyInstrAtomics.td-WebAssembly Atomic codegen support-*- tablegen -*-
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// WebAssembly Atomic operand code-gen constructs.
 ///
 //===----------------------------------------------------------------------===//
 
+let UseNamedOperandTable = 1 in
 multiclass ATOMIC_I<dag oops_r, dag iops_r, dag oops_s, dag iops_s,
                     list<dag> pattern_r, string asmstr_r = "",
                     string asmstr_s = "", bits<32> atomic_op = -1> {
   defm "" : I<oops_r, iops_r, oops_s, iops_s, pattern_r, asmstr_r, asmstr_s,
               !or(0xfe00, !and(0xff, atomic_op))>,
             Requires<[HasAtomics]>;
 }
 

 // Consider adding a pass after instruction selection that optimizes this case
 // if it is frequent.
 
 multiclass WebAssemblyTerRMW<WebAssemblyRegClass rc, string name,
                              int atomic_op> {
   defm "" :
     ATOMIC_I<(outs rc:$dst),
              (ins P2Align:$p2align, offset32_op:$off, I32:$addr, rc:$exp,
-                  rc:$new),
+                  rc:$new_),
              (outs), (ins P2Align:$p2align, offset32_op:$off), [],
-             !strconcat(name, "\t$dst, ${off}(${addr})${p2align}, $exp, $new"),
+             !strconcat(name, "\t$dst, ${off}(${addr})${p2align}, $exp, $new_"),
              !strconcat(name, "\t${off}${p2align}"), atomic_op>;
 }
 
 defm ATOMIC_RMW_CMPXCHG_I32 :
   WebAssemblyTerRMW<I32, "i32.atomic.rmw.cmpxchg", 0x48>;
 defm ATOMIC_RMW_CMPXCHG_I64 :
   WebAssemblyTerRMW<I64, "i64.atomic.rmw.cmpxchg", 0x49>;
 defm ATOMIC_RMW8_U_CMPXCHG_I32 :

llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.h

 #define LLVM_LIB_TARGET_WEBASSEMBLY_WEBASSEMBLYINSTRINFO_H
 
 #include "WebAssemblyRegisterInfo.h"
 #include "llvm/CodeGen/TargetInstrInfo.h"
 
 #define GET_INSTRINFO_HEADER
 #include "WebAssemblyGenInstrInfo.inc"
 
+#define GET_INSTRINFO_OPERAND_ENUM
+#include "WebAssemblyGenInstrInfo.inc"
+
 namespace llvm {
 
+namespace WebAssembly {
+
+int16_t getNamedOperandIdx(uint16_t Opcode, uint16_t NamedIndex);
+
+}
+
 class WebAssemblySubtarget;
 
 class WebAssemblyInstrInfo final : public WebAssemblyGenInstrInfo {
   const WebAssemblyRegisterInfo RI;
 
 public:
   explicit WebAssemblyInstrInfo(const WebAssemblySubtarget &STI);
 

llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrInfo.cpp

 #include "llvm/CodeGen/MachineRegisterInfo.h"
 using namespace llvm;
 
 #define DEBUG_TYPE "wasm-instr-info"
 
 #define GET_INSTRINFO_CTOR_DTOR
 #include "WebAssemblyGenInstrInfo.inc"
 
+// defines WebAssembly::getNamedOperandIdx
+#define GET_INSTRINFO_NAMED_OPS
+#include "WebAssemblyGenInstrInfo.inc"
+
 WebAssemblyInstrInfo::WebAssemblyInstrInfo(const WebAssemblySubtarget &STI)
     : WebAssemblyGenInstrInfo(WebAssembly::ADJCALLSTACKDOWN,
                               WebAssembly::ADJCALLSTACKUP,
                               WebAssembly::CATCHRET),
       RI(STI.getTargetTriple()) {}
 
 bool WebAssemblyInstrInfo::isReallyTriviallyReMaterializable(
     const MachineInstr &MI, AliasAnalysis *AA) const {

llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrMemory.td

def regPlusGA : PatFrag<(ops node:$addr, node:$off),
   return N->getFlags().hasNoUnsignedWrap();
 }]>;
 
 // We don't need a regPlusES because external symbols never have constant
 // offsets folded into them, so we can just use add.
 
 // Defines atomic and non-atomic loads, regular and extending.
 multiclass WebAssemblyLoad<WebAssemblyRegClass rc, string Name, int Opcode> {
-  let mayLoad = 1 in
+  let mayLoad = 1, UseNamedOperandTable = 1 in
   defm "": I<(outs rc:$dst),
              (ins P2Align:$p2align, offset32_op:$off, I32:$addr),
              (outs), (ins P2Align:$p2align, offset32_op:$off),
              [], !strconcat(Name, "\t$dst, ${off}(${addr})${p2align}"),
              !strconcat(Name, "\t${off}${p2align}"), Opcode>;
 }
 
 // Basic load.

 def : LoadPatExternSymOffOnly<i32, extloadi8, LOAD8_U_I32>;
 def : LoadPatExternSymOffOnly<i32, extloadi16, LOAD16_U_I32>;
 def : LoadPatExternSymOffOnly<i64, extloadi8, LOAD8_U_I64>;
 def : LoadPatExternSymOffOnly<i64, extloadi16, LOAD16_U_I64>;
 def : LoadPatExternSymOffOnly<i64, extloadi32, LOAD32_U_I64>;
 
 // Defines atomic and non-atomic stores, regular and truncating
 multiclass WebAssemblyStore<WebAssemblyRegClass rc, string Name, int Opcode> {
-  let mayStore = 1 in
+  let mayStore = 1, UseNamedOperandTable = 1 in
   defm "" : I<(outs),
               (ins P2Align:$p2align, offset32_op:$off, I32:$addr, rc:$val),
               (outs),
               (ins P2Align:$p2align, offset32_op:$off), [],
               !strconcat(Name, "\t${off}(${addr})${p2align}, $val"),
               !strconcat(Name, "\t${off}${p2align}"), Opcode>;
 }
 // Basic store.

llvm/trunk/lib/Target/WebAssembly/WebAssemblyInstrSIMD.td

 def LaneIdx#SIZE : ImmLeaf<i32, "return 0 <= Imm && Imm < "#SIZE#";">;
 
 //===----------------------------------------------------------------------===//
 // Load and store
 //===----------------------------------------------------------------------===//
 
 // Load: v128.load
 multiclass SIMDLoad<ValueType vec_t> {
-  let mayLoad = 1 in
+  let mayLoad = 1, UseNamedOperandTable = 1 in
   defm LOAD_#vec_t :
-    SIMD_I<(outs V128:$dst), (ins P2Align:$align, offset32_op:$off, I32:$addr),
-           (outs), (ins P2Align:$align, offset32_op:$off), [],
-           "v128.load\t$dst, ${off}(${addr})$align",
-           "v128.load\t$off$align", 0>;
+    SIMD_I<(outs V128:$dst), (ins P2Align:$p2align, offset32_op:$off, I32:$addr),
+           (outs), (ins P2Align:$p2align, offset32_op:$off), [],
+           "v128.load\t$dst, ${off}(${addr})$p2align",
+           "v128.load\t$off$p2align", 0>;
 }
 
 foreach vec_t = [v16i8, v8i16, v4i32, v2i64, v4f32, v2f64] in {
 defm "" : SIMDLoad<vec_t>;
 
 // Def load and store patterns from WebAssemblyInstrMemory.td for vector types
 def : LoadPatNoOffset<vec_t, load, !cast<NI>("LOAD_"#vec_t)>;
 def : LoadPatImmOff<vec_t, load, regPlusImm, !cast<NI>("LOAD_"#vec_t)>;
 def : LoadPatImmOff<vec_t, load, or_is_add, !cast<NI>("LOAD_"#vec_t)>;
 def : LoadPatGlobalAddr<vec_t, load, !cast<NI>("LOAD_"#vec_t)>;
 def : LoadPatExternalSym<vec_t, load, !cast<NI>("LOAD_"#vec_t)>;
 def : LoadPatOffsetOnly<vec_t, load, !cast<NI>("LOAD_"#vec_t)>;
 def : LoadPatGlobalAddrOffOnly<vec_t, load, !cast<NI>("LOAD_"#vec_t)>;
 def : LoadPatExternSymOffOnly<vec_t, load, !cast<NI>("LOAD_"#vec_t)>;
 }
 
 // Store: v128.store
 multiclass SIMDStore<ValueType vec_t> {
-  let mayStore = 1 in
+  let mayStore = 1, UseNamedOperandTable = 1 in
   defm STORE_#vec_t :
-    SIMD_I<(outs), (ins P2Align:$align, offset32_op:$off, I32:$addr, V128:$vec),
-           (outs), (ins P2Align:$align, offset32_op:$off), [],
-           "v128.store\t${off}(${addr})$align, $vec",
-           "v128.store\t$off$align", 1>;
+    SIMD_I<(outs), (ins P2Align:$p2align, offset32_op:$off, I32:$addr, V128:$vec),
+           (outs), (ins P2Align:$p2align, offset32_op:$off), [],
+           "v128.store\t${off}(${addr})$p2align, $vec",
+           "v128.store\t$off$p2align", 1>;
 }
 
 foreach vec_t = [v16i8, v8i16, v4i32, v2i64, v4f32, v2f64] in {
 defm "" : SIMDStore<vec_t>;
 
 // Def load and store patterns from WebAssemblyInstrMemory.td for vector types
 def : StorePatNoOffset<vec_t, store, !cast<NI>("STORE_"#vec_t)>;
 def : StorePatImmOff<vec_t, store, regPlusImm, !cast<NI>("STORE_"#vec_t)>;

llvm/trunk/lib/Target/WebAssembly/WebAssemblyRegisterInfo.cpp

void WebAssemblyRegisterInfo::eliminateFrameIndex(
 
   assert(MFI.getObjectSize(FrameIndex) != 0 &&
          "We assume that variable-sized objects have already been lowered, "
          "and don't use FrameIndex operands.");
   unsigned FrameRegister = getFrameRegister(MF);
 
   // If this is the address operand of a load or store, make it relative to SP
   // and fold the frame offset directly in.
-  if ((MI.mayLoad() && FIOperandNum == WebAssembly::LoadAddressOperandNo) ||
-      (MI.mayStore() && FIOperandNum == WebAssembly::StoreAddressOperandNo)) {
-    assert(FrameOffset >= 0 && MI.getOperand(FIOperandNum - 1).getImm() >= 0);
-    int64_t Offset = MI.getOperand(FIOperandNum - 1).getImm() + FrameOffset;
+  unsigned AddrOperandNum = WebAssembly::getNamedOperandIdx(
+      MI.getOpcode(), WebAssembly::OpName::addr);
+  if (AddrOperandNum == FIOperandNum) {
+    unsigned OffsetOperandNum = WebAssembly::getNamedOperandIdx(
+        MI.getOpcode(), WebAssembly::OpName::off);
+    assert(FrameOffset >= 0 && MI.getOperand(OffsetOperandNum).getImm() >= 0);
+    int64_t Offset = MI.getOperand(OffsetOperandNum).getImm() + FrameOffset;
 
     if (static_cast<uint64_t>(Offset) <= std::numeric_limits<uint32_t>::max()) {
-      MI.getOperand(FIOperandNum - 1).setImm(Offset);
+      MI.getOperand(OffsetOperandNum).setImm(Offset);
       MI.getOperand(FIOperandNum)
           .ChangeToRegister(FrameRegister, /*IsDef=*/false);
       return;
     }
   }
 
   // If this is an address being added to a constant, fold the frame offset
   // into the constant.

llvm/trunk/lib/Target/WebAssembly/WebAssemblySetP2AlignOperands.cpp

 //=- WebAssemblySetP2AlignOperands.cpp - Set alignments on loads and stores -=//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 ///
 /// \file
 /// This file sets the p2align operands on load and store instructions.
 ///
 //===----------------------------------------------------------------------===//
 
 #include "MCTargetDesc/WebAssemblyMCTargetDesc.h"
 #include "WebAssembly.h"
+#include "WebAssemblyInstrInfo.h"
 #include "WebAssemblyMachineFunctionInfo.h"
 #include "llvm/CodeGen/MachineBlockFrequencyInfo.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 using namespace llvm;
 
LLVM_DEBUG({
     dbgs() << "********** Set p2align Operands **********\n"
            << "********** Function: " << MF.getName() << '\n';
   });
 
   bool Changed = false;
 
   for (auto &MBB : MF) {
     for (auto &MI : MBB) {
-      switch (MI.getOpcode()) {
-      case WebAssembly::LOAD_I32:
-      case WebAssembly::LOAD_I64:
-      case WebAssembly::LOAD_F32:
-      case WebAssembly::LOAD_F64:
-      case WebAssembly::LOAD_v16i8:
-      case WebAssembly::LOAD_v8i16:
-      case WebAssembly::LOAD_v4i32:
-      case WebAssembly::LOAD_v2i64:
-      case WebAssembly::LOAD_v4f32:
-      case WebAssembly::LOAD_v2f64:
-      case WebAssembly::LOAD8_S_I32:
-      case WebAssembly::LOAD8_U_I32:
-      case WebAssembly::LOAD16_S_I32:
-      case WebAssembly::LOAD16_U_I32:
-      case WebAssembly::LOAD8_S_I64:
-      case WebAssembly::LOAD8_U_I64:
-      case WebAssembly::LOAD16_S_I64:
-      case WebAssembly::LOAD16_U_I64:
-      case WebAssembly::LOAD32_S_I64:
-      case WebAssembly::LOAD32_U_I64:
-      case WebAssembly::ATOMIC_LOAD_I32:
-      case WebAssembly::ATOMIC_LOAD8_U_I32:
-      case WebAssembly::ATOMIC_LOAD16_U_I32:
-      case WebAssembly::ATOMIC_LOAD_I64:
-      case WebAssembly::ATOMIC_LOAD8_U_I64:
-      case WebAssembly::ATOMIC_LOAD16_U_I64:
-      case WebAssembly::ATOMIC_LOAD32_U_I64:
-      case WebAssembly::ATOMIC_RMW8_U_ADD_I32:
-      case WebAssembly::ATOMIC_RMW8_U_ADD_I64:
-      case WebAssembly::ATOMIC_RMW8_U_SUB_I32:
-      case WebAssembly::ATOMIC_RMW8_U_SUB_I64:
-      case WebAssembly::ATOMIC_RMW8_U_AND_I32:
-      case WebAssembly::ATOMIC_RMW8_U_AND_I64:
-      case WebAssembly::ATOMIC_RMW8_U_OR_I32:
-      case WebAssembly::ATOMIC_RMW8_U_OR_I64:
-      case WebAssembly::ATOMIC_RMW8_U_XOR_I32:
-      case WebAssembly::ATOMIC_RMW8_U_XOR_I64:
-      case WebAssembly::ATOMIC_RMW8_U_XCHG_I32:
-      case WebAssembly::ATOMIC_RMW8_U_XCHG_I64:
-      case WebAssembly::ATOMIC_RMW8_U_CMPXCHG_I32:
-      case WebAssembly::ATOMIC_RMW8_U_CMPXCHG_I64:
-      case WebAssembly::ATOMIC_RMW16_U_ADD_I32:
-      case WebAssembly::ATOMIC_RMW16_U_ADD_I64:
-      case WebAssembly::ATOMIC_RMW16_U_SUB_I32:
-      case WebAssembly::ATOMIC_RMW16_U_SUB_I64:
-      case WebAssembly::ATOMIC_RMW16_U_AND_I32:
-      case WebAssembly::ATOMIC_RMW16_U_AND_I64:
-      case WebAssembly::ATOMIC_RMW16_U_OR_I32:
-      case WebAssembly::ATOMIC_RMW16_U_OR_I64:
-      case WebAssembly::ATOMIC_RMW16_U_XOR_I32:
-      case WebAssembly::ATOMIC_RMW16_U_XOR_I64:
-      case WebAssembly::ATOMIC_RMW16_U_XCHG_I32:
-      case WebAssembly::ATOMIC_RMW16_U_XCHG_I64:
-      case WebAssembly::ATOMIC_RMW16_U_CMPXCHG_I32:
-      case WebAssembly::ATOMIC_RMW16_U_CMPXCHG_I64:
-      case WebAssembly::ATOMIC_RMW_ADD_I32:
-      case WebAssembly::ATOMIC_RMW32_U_ADD_I64:
-      case WebAssembly::ATOMIC_RMW_SUB_I32:
-      case WebAssembly::ATOMIC_RMW32_U_SUB_I64:
-      case WebAssembly::ATOMIC_RMW_AND_I32:
-      case WebAssembly::ATOMIC_RMW32_U_AND_I64:
-      case WebAssembly::ATOMIC_RMW_OR_I32:
-      case WebAssembly::ATOMIC_RMW32_U_OR_I64:
-      case WebAssembly::ATOMIC_RMW_XOR_I32:
-      case WebAssembly::ATOMIC_RMW32_U_XOR_I64:
-      case WebAssembly::ATOMIC_RMW_XCHG_I32:
-      case WebAssembly::ATOMIC_RMW32_U_XCHG_I64:
-      case WebAssembly::ATOMIC_RMW_CMPXCHG_I32:
-      case WebAssembly::ATOMIC_RMW32_U_CMPXCHG_I64:
-      case WebAssembly::ATOMIC_RMW_ADD_I64:
-      case WebAssembly::ATOMIC_RMW_SUB_I64:
-      case WebAssembly::ATOMIC_RMW_AND_I64:
-      case WebAssembly::ATOMIC_RMW_OR_I64:
-      case WebAssembly::ATOMIC_RMW_XOR_I64:
-      case WebAssembly::ATOMIC_RMW_XCHG_I64:
-      case WebAssembly::ATOMIC_RMW_CMPXCHG_I64:
-      case WebAssembly::ATOMIC_NOTIFY:
-      case WebAssembly::ATOMIC_WAIT_I32:
-      case WebAssembly::ATOMIC_WAIT_I64:
-        rewriteP2Align(MI, WebAssembly::LoadP2AlignOperandNo);
-        break;
-      case WebAssembly::STORE_I32:
-      case WebAssembly::STORE_I64:
-      case WebAssembly::STORE_F32:
-      case WebAssembly::STORE_F64:
-      case WebAssembly::STORE_v16i8:
-      case WebAssembly::STORE_v8i16:
-      case WebAssembly::STORE_v4i32:
-      case WebAssembly::STORE_v2i64:
-      case WebAssembly::STORE_v4f32:
-      case WebAssembly::STORE_v2f64:
-      case WebAssembly::STORE8_I32:
-      case WebAssembly::STORE16_I32:
-      case WebAssembly::STORE8_I64:
-      case WebAssembly::STORE16_I64:
-      case WebAssembly::STORE32_I64:
-      case WebAssembly::ATOMIC_STORE_I32:
-      case WebAssembly::ATOMIC_STORE8_I32:
-      case WebAssembly::ATOMIC_STORE16_I32:
-      case WebAssembly::ATOMIC_STORE_I64:
-      case WebAssembly::ATOMIC_STORE8_I64:
-      case WebAssembly::ATOMIC_STORE16_I64:
-      case WebAssembly::ATOMIC_STORE32_I64:
-        rewriteP2Align(MI, WebAssembly::StoreP2AlignOperandNo);
-        break;
-      default:
-        break;
+      int16_t P2AlignOpNum = WebAssembly::getNamedOperandIdx(
+          MI.getOpcode(), WebAssembly::OpName::p2align);
+      if (P2AlignOpNum != -1) {
+        rewriteP2Align(MI, P2AlignOpNum);
+        Changed = true;
       }
     }
   }
 
   return Changed;
 }

llvm/trunk/test/CodeGen/WebAssembly/bulk-memory.ll

 ; BULK-MEM-NEXT: .functype memset_1024 (i32, i32) -> ()
 ; BULK-MEM-NEXT: i32.const $push[[L0:[0-9]+]]=, 1024
 ; BULK-MEM-NEXT: memory.fill 0, $0, $1, $pop[[L0]]
 ; BULK-MEM-NEXT: return
 define void @memset_1024(i8* %dest, i8 %val) {
   call void @llvm.memset.p0i8.i32(i8* %dest, i8 %val, i32 1024, i1 0)
   ret void
 }
+
+; The following tests check that frame index elimination works for
+; bulk memory instructions. The stack pointer is bumped by 16 instead
+; of 10 because the stack pointer in WebAssembly is currently always
+; 16-byte aligned, even in leaf functions, although it is not written
+; back to the global in this case.
+
+; TODO: Change TransientStackAlignment to 1 to avoid this extra
+; arithmetic. This will require forcing the use of StackAlignment in
+; PrologEpilogEmitter.cpp when
+; WebAssemblyFrameLowering::needsSPWriteback would be true.
+
+; CHECK-LABEL: memcpy_alloca_src:
+; NO-BULK-MEM-NOT: memory.copy
+; BULK-MEM-NEXT: .functype memcpy_alloca_src (i32) -> ()
+; BULK-MEM-NEXT: global.get $push[[L0:[0-9]+]]=, __stack_pointer
+; BULK-MEM-NEXT: i32.const $push[[L1:[0-9]+]]=, 16
+; BULK-MEM-NEXT: i32.sub $push[[L2:[0-9]+]]=, $pop[[L0]], $pop[[L1]]
+; BULK-MEM-NEXT: i32.const $push[[L3:[0-9]+]]=, 6
+; BULK-MEM-NEXT: i32.add $push[[L4:[0-9]+]]=, $pop[[L2]], $pop[[L3]]
+; BULK-MEM-NEXT: i32.const $push[[L5:[0-9]+]]=, 10
+; BULK-MEM-NEXT: memory.copy 0, 0, $0, $pop[[L4]], $pop[[L5]]
+; BULK-MEM-NEXT: return
+define void @memcpy_alloca_src(i8* %dst) {
+  %a = alloca [10 x i8]
+  %p = bitcast [10 x i8]* %a to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dst, i8* %p, i32 10, i1 false)
+  ret void
+}
+
+; CHECK-LABEL: memcpy_alloca_dst:
+; NO-BULK-MEM-NOT: memory.copy
+; BULK-MEM-NEXT: .functype memcpy_alloca_dst (i32) -> ()
+; BULK-MEM-NEXT: global.get $push[[L0:[0-9]+]]=, __stack_pointer
+; BULK-MEM-NEXT: i32.const $push[[L1:[0-9]+]]=, 16
+; BULK-MEM-NEXT: i32.sub $push[[L2:[0-9]+]]=, $pop[[L0]], $pop[[L1]]
+; BULK-MEM-NEXT: i32.const $push[[L3:[0-9]+]]=, 6
+; BULK-MEM-NEXT: i32.add $push[[L4:[0-9]+]]=, $pop[[L2]], $pop[[L3]]
+; BULK-MEM-NEXT: i32.const $push[[L5:[0-9]+]]=, 10
+; BULK-MEM-NEXT: memory.copy 0, 0, $pop[[L4]], $0, $pop[[L5]]
+; BULK-MEM-NEXT: return
+define void @memcpy_alloca_dst(i8* %src) {
+  %a = alloca [10 x i8]
+  %p = bitcast [10 x i8]* %a to i8*
+  call void @llvm.memcpy.p0i8.p0i8.i32(i8* %p, i8* %src, i32 10, i1 false)
+  ret void
+}
+
+; CHECK-LABEL: memset_alloca:
+; NO-BULK-MEM-NOT: memory.fill
+; BULK-MEM-NEXT: .functype memset_alloca (i32) -> ()
+; BULK-MEM-NEXT: global.get $push[[L0:[0-9]+]]=, __stack_pointer
+; BULK-MEM-NEXT: i32.const $push[[L1:[0-9]+]]=, 16
+; BULK-MEM-NEXT: i32.sub $push[[L2:[0-9]+]]=, $pop[[L0]], $pop[[L1]]
+; BULK-MEM-NEXT: i32.const $push[[L3:[0-9]+]]=, 6
+; BULK-MEM-NEXT: i32.add $push[[L4:[0-9]+]]=, $pop[[L2]], $pop[[L3]]
+; BULK-MEM-NEXT: i32.const $push[[L5:[0-9]+]]=, 10
+; BULK-MEM-NEXT: memory.fill 0, $pop[[L4]], $0, $pop[[L5]]
+; BULK-MEM-NEXT: return
+define void @memset_alloca(i8 %val) {
+  %a = alloca [10 x i8]
+  %p = bitcast [10 x i8]* %a to i8*
+  call void @llvm.memset.p0i8.i32(i8* %p, i8 %val, i32 10, i1 false)
+  ret void
+}