[wasm] Make LiftoffRegList::ForRegs a constructor

The 'ForRegs' method is not needed for clarity of the code, it's pretty clear what to construct a register list from. Hence turn the static {LiftoffRegList::ForRegs} method into a constructor. This makes the code more concise. Also, turn the for loop into a C++17 folding expression, which might generate better code because the loop will automatically be unrolled. R=thibaudm@chromium.org Bug: v8:12425 Change-Id: Ic4446f23022db5f17420303d45b9c15fa5daff60 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3572041Reviewed-by: Thibaud Michaud <thibaudm@chromium.org> Commit-Queue: Clemens Backes <clemensb@chromium.org> Cr-Commit-Position: refs/heads/main@{#79815}

[wasm] Make LiftoffRegList::ForRegs a constructor
The 'ForRegs' method is not needed for clarity of the code, it's pretty clear what to construct a register list from. Hence turn the static {LiftoffRegList::ForRegs} method into a constructor. This makes the code more concise. Also, turn the for loop into a C++17 folding expression, which might generate better code because the loop will automatically be unrolled. R=thibaudm@chromium.org Bug: v8:12425 Change-Id: Ic4446f23022db5f17420303d45b9c15fa5daff60 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3572041Reviewed-by: Thibaud Michaud <thibaudm@chromium.org> Commit-Queue: Clemens Backes <clemensb@chromium.org> Cr-Commit-Position: refs/heads/main@{#79815}
ea96bd76 · Clemens Backes · V8 LUCI CQ · 5cd917d5 · ea96bd76 · ea96bd76
Commit ea96bd76 authored Apr 05, 2022 by Clemens Backes Committed by V8 LUCI CQ Apr 06, 2022
12 changed files
--- a/src/wasm/baseline/arm/liftoff-assembler-arm.h
+++ b/src/wasm/baseline/arm/liftoff-assembler-arm.h
@@ -155,8 +155,8 @@ inline void I64Binop(LiftoffAssembler* assm, LiftoffRegister dst,
                     LiftoffRegister lhs, LiftoffRegister rhs) {
  Register dst_low = dst.low_gp();
  if (dst_low == lhs.high_gp() || dst_low == rhs.high_gp()) {
-    dst_low = assm->GetUnusedRegister(
+    dst_low =
-                      kGpReg, LiftoffRegList::ForRegs(lhs, rhs, dst.high_gp()))
+        assm->GetUnusedRegister(kGpReg, LiftoffRegList{lhs, rhs, dst.high_gp()})
            .gp();
  }
  (assm->*op)(dst_low, lhs.low_gp(), rhs.low_gp(), SetCC, al);
@@ -193,7 +193,7 @@ inline void I64Shiftop(LiftoffAssembler* assm, LiftoffRegister dst,
  // Left shift writes {dst_high} then {dst_low}, right shifts write {dst_low}
  // then {dst_high}.
  Register clobbered_dst_reg = is_left_shift ? dst_high : dst_low;
-  LiftoffRegList pinned = LiftoffRegList::ForRegs(clobbered_dst_reg, src);
+  LiftoffRegList pinned = {clobbered_dst_reg, src};
  Register amount_capped =
      pinned.set(assm->GetUnusedRegister(kGpReg, pinned)).gp();
  assm->and_(amount_capped, amount, Operand(0x3F));
@@ -950,8 +950,7 @@ inline void AtomicBinop32(LiftoffAssembler* lasm, Register dst_addr,
                          StoreType type,
                          void (*op)(LiftoffAssembler*, Register, Register,
                                     Register)) {
-  LiftoffRegList pinned =
+  LiftoffRegList pinned = {dst_addr, offset_reg, value, result};
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result);
  switch (type.value()) {
    case StoreType::kI64Store8:
      __ LoadConstant(result.high(), WasmValue(0));
@@ -1002,16 +1001,14 @@ inline void AtomicOp64(LiftoffAssembler* lasm, Register dst_addr,
  // Make sure {dst_low} and {dst_high} are not occupied by any other value.
  Register value_low = value.low_gp();
  Register value_high = value.high_gp();
-  LiftoffRegList pinned = LiftoffRegList::ForRegs(
+  LiftoffRegList pinned = {dst_addr,   offset_reg, value_low,
-      dst_addr, offset_reg, value_low, value_high, dst_low, dst_high);
+                           value_high, dst_low,    dst_high};
  __ ClearRegister(dst_low, {&dst_addr, &offset_reg, &value_low, &value_high},
                   pinned);
-  pinned = pinned |
+  pinned = pinned | LiftoffRegList{dst_addr, offset_reg, value_low, value_high};
-           LiftoffRegList::ForRegs(dst_addr, offset_reg, value_low, value_high);
  __ ClearRegister(dst_high, {&dst_addr, &offset_reg, &value_low, &value_high},
                   pinned);
-  pinned = pinned |
+  pinned = pinned | LiftoffRegList{dst_addr, offset_reg, value_low, value_high};
-           LiftoffRegList::ForRegs(dst_addr, offset_reg, value_low, value_high);
  // Make sure that {result}, if it exists, also does not overlap with
  // {dst_low} and {dst_high}. We don't have to transfer the value stored in
@@ -1275,7 +1272,7 @@ void LiftoffAssembler::AtomicCompareExchange(
  void (Assembler::*load)(Register, Register, Condition) = nullptr;
  void (Assembler::*store)(Register, Register, Register, Condition) = nullptr;
-  LiftoffRegList pinned = LiftoffRegList::ForRegs(dst_addr, offset_reg);
+  LiftoffRegList pinned = {dst_addr, offset_reg};
  // We need to remember the high word of {result}, so we can set it to zero in
  // the end if necessary.
  Register result_high = no_reg;
@@ -1614,7 +1611,7 @@ inline void GeneratePopCnt(Assembler* assm, Register dst, Register src,
 }  // namespace liftoff
 bool LiftoffAssembler::emit_i32_popcnt(Register dst, Register src) {
-  LiftoffRegList pinned = LiftoffRegList::ForRegs(dst);
+  LiftoffRegList pinned = {dst};
  Register scratch1 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register scratch2 = GetUnusedRegister(kGpReg, pinned).gp();
  liftoff::GeneratePopCnt(this, dst, src, scratch1, scratch2);
@@ -1855,7 +1852,7 @@ bool LiftoffAssembler::emit_i64_popcnt(LiftoffRegister dst,
  // overwrite the second src register before using it.
  Register src1 = src.high_gp() == dst.low_gp() ? src.high_gp() : src.low_gp();
  Register src2 = src.high_gp() == dst.low_gp() ? src.low_gp() : src.high_gp();
-  LiftoffRegList pinned = LiftoffRegList::ForRegs(dst, src2);
+  LiftoffRegList pinned = {dst, src2};
  Register scratch1 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register scratch2 = GetUnusedRegister(kGpReg, pinned).gp();
  liftoff::GeneratePopCnt(this, dst.low_gp(), src1, scratch1, scratch2);
@@ -2924,12 +2921,12 @@ void LiftoffAssembler::emit_i64x2_mul(LiftoffRegister dst, LiftoffRegister lhs,
  QwNeonRegister tmp2 = right;
  LiftoffRegList used_plus_dst =
-      cache_state()->used_registers | LiftoffRegList::ForRegs(dst);
+      cache_state()->used_registers | LiftoffRegList{dst};
  if (used_plus_dst.has(lhs) && used_plus_dst.has(rhs)) {
    tmp1 = temps.AcquireQ();
    // We only have 1 scratch Q register, so acquire another ourselves.
-    LiftoffRegList pinned = LiftoffRegList::ForRegs(dst);
+    LiftoffRegList pinned = {dst};
    LiftoffRegister unused_pair = GetUnusedRegister(kFpRegPair, pinned);
    tmp2 = liftoff::GetSimd128Register(unused_pair);
  } else if (used_plus_dst.has(lhs)) {
@@ -3055,7 +3052,7 @@ void LiftoffAssembler::emit_i32x4_bitmask(LiftoffRegister dst,
  if (cache_state()->is_used(src)) {
    // We only have 1 scratch Q register, so try and reuse src.
-    LiftoffRegList pinned = LiftoffRegList::ForRegs(src);
+    LiftoffRegList pinned = {src};
    LiftoffRegister unused_pair = GetUnusedRegister(kFpRegPair, pinned);
    mask = liftoff::GetSimd128Register(unused_pair);
  }
@@ -3240,7 +3237,7 @@ void LiftoffAssembler::emit_i16x8_bitmask(LiftoffRegister dst,
  if (cache_state()->is_used(src)) {
    // We only have 1 scratch Q register, so try and reuse src.
-    LiftoffRegList pinned = LiftoffRegList::ForRegs(src);
+    LiftoffRegList pinned = {src};
    LiftoffRegister unused_pair = GetUnusedRegister(kFpRegPair, pinned);
    mask = liftoff::GetSimd128Register(unused_pair);
  }
@@ -3555,7 +3552,7 @@ void LiftoffAssembler::emit_i8x16_bitmask(LiftoffRegister dst,
  if (cache_state()->is_used(src)) {
    // We only have 1 scratch Q register, so try and reuse src.
-    LiftoffRegList pinned = LiftoffRegList::ForRegs(src);
+    LiftoffRegList pinned = {src};
    LiftoffRegister unused_pair = GetUnusedRegister(kFpRegPair, pinned);
    mask = liftoff::GetSimd128Register(unused_pair);
  }

--- a/src/wasm/baseline/arm64/liftoff-assembler-arm64.h
+++ b/src/wasm/baseline/arm64/liftoff-assembler-arm64.h
@@ -636,8 +636,7 @@ inline void AtomicBinop(LiftoffAssembler* lasm, Register dst_addr,
                        Register offset_reg, uintptr_t offset_imm,
                        LiftoffRegister value, LiftoffRegister result,
                        StoreType type, Binop op) {
-  LiftoffRegList pinned =
+  LiftoffRegList pinned = {dst_addr, offset_reg, value, result};
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result);
  Register store_result = pinned.set(__ GetUnusedRegister(kGpReg, pinned)).gp();
  // {LiftoffCompiler::AtomicBinop} ensures that {result} is unique.
@@ -823,8 +822,7 @@ void LiftoffAssembler::AtomicCompareExchange(
    Register dst_addr, Register offset_reg, uintptr_t offset_imm,
    LiftoffRegister expected, LiftoffRegister new_value, LiftoffRegister result,
    StoreType type) {
-  LiftoffRegList pinned =
+  LiftoffRegList pinned = {dst_addr, offset_reg, expected, new_value};
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, expected, new_value);
  Register result_reg = result.gp();
  if (pinned.has(result)) {
@@ -2511,7 +2509,7 @@ void LiftoffAssembler::emit_i8x16_shuffle(LiftoffRegister dst,
  VRegister temp = dst.fp();
  if (dst == lhs || dst == rhs) {
    // dst overlaps with lhs or rhs, so we need a temporary.
-    temp = GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(lhs, rhs)).fp();
+    temp = GetUnusedRegister(kFpReg, LiftoffRegList{lhs, rhs}).fp();
  }
  UseScratchRegisterScope scope(this);

--- a/src/wasm/baseline/ia32/liftoff-assembler-ia32.h
+++ b/src/wasm/baseline/ia32/liftoff-assembler-ia32.h
--- a/src/wasm/baseline/liftoff-assembler.h
+++ b/src/wasm/baseline/liftoff-assembler.h
@@ -1591,8 +1591,7 @@ void EmitI64IndependentHalfOperation(LiftoffAssembler* assm,
    return;
  }
  // Otherwise, we need a temporary register.
-  Register tmp =
+  Register tmp = assm->GetUnusedRegister(kGpReg, LiftoffRegList{lhs, rhs}).gp();
-      assm->GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(lhs, rhs)).gp();
  (assm->*op)(tmp, lhs.low_gp(), rhs.low_gp());
  (assm->*op)(dst.high_gp(), lhs.high_gp(), rhs.high_gp());
  assm->Move(dst.low_gp(), tmp, kI32);
@@ -1619,8 +1618,7 @@ void EmitI64IndependentHalfOperationImm(LiftoffAssembler* assm,
    return;
  }
  // Otherwise, we need a temporary register.
-  Register tmp =
+  Register tmp = assm->GetUnusedRegister(kGpReg, LiftoffRegList{lhs}).gp();
-      assm->GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(lhs)).gp();
  (assm->*op)(tmp, lhs.low_gp(), low_word);
  (assm->*op)(dst.high_gp(), lhs.high_gp(), high_word);
  assm->Move(dst.low_gp(), tmp, kI32);

--- a/src/wasm/baseline/liftoff-compiler.cc
+++ b/src/wasm/baseline/liftoff-compiler.cc
--- a/src/wasm/baseline/liftoff-register.h
+++ b/src/wasm/baseline/liftoff-register.h
@@ -347,6 +347,17 @@ class LiftoffRegList {
  constexpr LiftoffRegList() = default;
+  // Allow to construct LiftoffRegList from a number of
+  // {Register|DoubleRegister|LiftoffRegister}.
+  template <
+      typename... Regs,
+      typename = std::enable_if_t<std::conjunction_v<std::disjunction<
+          std::is_same<Register, Regs>, std::is_same<DoubleRegister, Regs>,
+          std::is_same<LiftoffRegister, Regs>>...>>>
+  constexpr LiftoffRegList(Regs... regs) {
+    (..., set(regs));
+  }
  constexpr Register set(Register reg) {
    return set(LiftoffRegister(reg)).gp();
  }
@@ -461,13 +472,6 @@ class LiftoffRegList {
    return LiftoffRegList(bits);
  }
-  template <typename... Regs>
-  static LiftoffRegList ForRegs(Regs... regs) {
-    LiftoffRegList list;
-    for (LiftoffRegister reg : {LiftoffRegister(regs)...}) list.set(reg);
-    return list;
-  }
 private:
  // Unchecked constructor. Only use for valid bits.
  explicit constexpr LiftoffRegList(storage_t bits) : regs_(bits) {}

--- a/src/wasm/baseline/loong64/liftoff-assembler-loong64.h
+++ b/src/wasm/baseline/loong64/liftoff-assembler-loong64.h
@@ -599,8 +599,7 @@ void LiftoffAssembler::AtomicStore(Register dst_addr, Register offset_reg,
  void LiftoffAssembler::Atomic##name(                                   \
      Register dst_addr, Register offset_reg, uintptr_t offset_imm,      \
      LiftoffRegister value, LiftoffRegister result, StoreType type) {   \
-    LiftoffRegList pinned =                                              \
+    LiftoffRegList pinned = {dst_addr, offset_reg, value, result};       \
-        LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result);    \
    Register temp0 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp(); \
    Register temp1 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp(); \
    Register temp2 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp(); \
@@ -655,8 +654,7 @@ ATOMIC_BINOP_CASE(Xor, Xor, Xor, xor)
 void LiftoffAssembler::AtomicSub(Register dst_addr, Register offset_reg,
                                 uintptr_t offset_imm, LiftoffRegister value,
                                 LiftoffRegister result, StoreType type) {
-  LiftoffRegList pinned =
+  LiftoffRegList pinned = {dst_addr, offset_reg, value, result};
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result);
  Register temp0 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp1 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp2 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
@@ -714,8 +712,7 @@ void LiftoffAssembler::AtomicExchange(Register dst_addr, Register offset_reg,
                                      uintptr_t offset_imm,
                                      LiftoffRegister value,
                                      LiftoffRegister result, StoreType type) {
-  LiftoffRegList pinned =
+  LiftoffRegList pinned = {dst_addr, offset_reg, value, result};
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result);
  Register temp0 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp1 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp2 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
@@ -790,8 +787,7 @@ void LiftoffAssembler::AtomicCompareExchange(
    Register dst_addr, Register offset_reg, uintptr_t offset_imm,
    LiftoffRegister expected, LiftoffRegister new_value, LiftoffRegister result,
    StoreType type) {
-  LiftoffRegList pinned = LiftoffRegList::ForRegs(dst_addr, offset_reg,
+  LiftoffRegList pinned = {dst_addr, offset_reg, expected, new_value, result};
-                                                  expected, new_value, result);
  Register temp0 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp1 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp2 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
@@ -1320,10 +1316,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      TurboAssembler::bstrpick_w(dst.gp(), src.gp(), 31, 0);
      return true;
    case kExprI32SConvertF32: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_s(rounded.fp(), src.fp());
@@ -1343,10 +1338,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI32UConvertF32: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_s(rounded.fp(), src.fp());
@@ -1364,10 +1358,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI32SConvertF64: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_d(rounded.fp(), src.fp());
@@ -1381,10 +1374,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI32UConvertF64: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_d(rounded.fp(), src.fp());
@@ -1406,10 +1398,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      TurboAssembler::bstrpick_d(dst.gp(), src.gp(), 31, 0);
      return true;
    case kExprI64SConvertF32: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_s(rounded.fp(), src.fp());
@@ -1438,10 +1429,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI64SConvertF64: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_d(rounded.fp(), src.fp());
@@ -1473,8 +1463,7 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      movfr2gr_d(dst.gp(), src.fp());
      return true;
    case kExprF32SConvertI32: {
-      LiftoffRegister scratch =
+      LiftoffRegister scratch = GetUnusedRegister(kFpReg, LiftoffRegList{dst});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dst));
      movgr2fr_w(scratch.fp(), src.gp());
      ffint_s_w(dst.fp(), scratch.fp());
      return true;
@@ -1489,8 +1478,7 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      TurboAssembler::FmoveLow(dst.fp(), src.gp());
      return true;
    case kExprF64SConvertI32: {
-      LiftoffRegister scratch =
+      LiftoffRegister scratch = GetUnusedRegister(kFpReg, LiftoffRegList{dst});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dst));
      movgr2fr_w(scratch.fp(), src.gp());
      ffint_d_w(dst.fp(), scratch.fp());
      return true;
@@ -1635,7 +1623,7 @@ void LiftoffAssembler::emit_i32_set_cond(LiftoffCondition liftoff_cond,
  Condition cond = liftoff::ToCondition(liftoff_cond);
  Register tmp = dst;
  if (dst == lhs || dst == rhs) {
-    tmp = GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(lhs, rhs)).gp();
+    tmp = GetUnusedRegister(kGpReg, LiftoffRegList{lhs, rhs}).gp();
  }
  // Write 1 as result.
  TurboAssembler::li(tmp, 1);
@@ -1658,7 +1646,7 @@ void LiftoffAssembler::emit_i64_set_cond(LiftoffCondition liftoff_cond,
  Condition cond = liftoff::ToCondition(liftoff_cond);
  Register tmp = dst;
  if (dst == lhs.gp() || dst == rhs.gp()) {
-    tmp = GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(lhs, rhs)).gp();
+    tmp = GetUnusedRegister(kGpReg, LiftoffRegList{lhs, rhs}).gp();
  }
  // Write 1 as result.
  TurboAssembler::li(tmp, 1);

--- a/src/wasm/baseline/mips/liftoff-assembler-mips.h
+++ b/src/wasm/baseline/mips/liftoff-assembler-mips.h
@@ -658,7 +658,7 @@ void LiftoffAssembler::Store(Register dst_addr, Register offset_reg,
 #if defined(V8_TARGET_BIG_ENDIAN)
  if (is_store_mem) {
-    pinned = pinned | LiftoffRegList::ForRegs(dst_op.rm(), src);
+    pinned = pinned | LiftoffRegList{dst_op.rm(), src};
    LiftoffRegister tmp = GetUnusedRegister(src.reg_class(), pinned);
    // Save original value.
    Move(tmp, src, type.value_type());
@@ -1022,8 +1022,7 @@ I32_SHIFTOP_I(shr, srl)
 void LiftoffAssembler::emit_i64_addi(LiftoffRegister dst, LiftoffRegister lhs,
                                     int64_t imm) {
-  LiftoffRegister imm_reg =
+  LiftoffRegister imm_reg = GetUnusedRegister(kFpReg, LiftoffRegList{dst, lhs});
-    GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dst, lhs));
  int32_t imm_low_word = static_cast<int32_t>(imm);
  int32_t imm_high_word = static_cast<int32_t>(imm >> 32);
  TurboAssembler::li(imm_reg.low_gp(), imm_low_word);
@@ -1092,7 +1091,7 @@ inline void Emit64BitShiftOperation(
    void (TurboAssembler::*emit_shift)(Register, Register, Register, Register,
                                       Register, Register, Register)) {
  Label move, done;
-  LiftoffRegList pinned = LiftoffRegList::ForRegs(dst, src, amount);
+  LiftoffRegList pinned = {dst, src, amount};
  // If some of destination registers are in use, get another, unused pair.
  // That way we prevent overwriting some input registers while shifting.
@@ -1377,10 +1376,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      TurboAssembler::Move(dst.gp(), src.low_gp());
      return true;
    case kExprI32SConvertF32: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_s_s(rounded.fp(), src.fp());
@@ -1400,10 +1398,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI32UConvertF32: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_s_s(rounded.fp(), src.fp());
@@ -1422,8 +1419,7 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI32SConvertF64: {
-      LiftoffRegister scratch =
+      LiftoffRegister scratch = GetUnusedRegister(kGpReg, LiftoffRegList{dst});
-          GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(dst));
      // Try a conversion to a signed integer.
      trunc_w_d(kScratchDoubleReg, src.fp());
@@ -1442,9 +1438,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      if ((IsMipsArchVariant(kMips32r2) || IsMipsArchVariant(kMips32r6)) &&
          IsFp64Mode()) {
        LiftoffRegister rounded =
-            GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
+            GetUnusedRegister(kFpReg, LiftoffRegList{src});
        LiftoffRegister converted_back =
-            GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+            GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
        // Real conversion.
        TurboAssembler::Trunc_d_d(rounded.fp(), src.fp());
@@ -1501,15 +1497,13 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      TurboAssembler::Mfhc1(dst.high_gp(), src.fp());
      return true;
    case kExprF32SConvertI32: {
-      LiftoffRegister scratch =
+      LiftoffRegister scratch = GetUnusedRegister(kFpReg, LiftoffRegList{dst});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dst));
      mtc1(src.gp(), scratch.fp());
      cvt_s_w(dst.fp(), scratch.fp());
      return true;
    }
    case kExprF32UConvertI32: {
-      LiftoffRegister scratch =
+      LiftoffRegister scratch = GetUnusedRegister(kFpReg, LiftoffRegList{dst});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dst));
      TurboAssembler::Cvt_d_uw(dst.fp(), src.gp(), scratch.fp());
      cvt_s_d(dst.fp(), dst.fp());
      return true;
@@ -1521,15 +1515,13 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      TurboAssembler::FmoveLow(dst.fp(), src.gp());
      return true;
    case kExprF64SConvertI32: {
-      LiftoffRegister scratch =
+      LiftoffRegister scratch = GetUnusedRegister(kFpReg, LiftoffRegList{dst});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dst));
      mtc1(src.gp(), scratch.fp());
      cvt_d_w(dst.fp(), scratch.fp());
      return true;
    }
    case kExprF64UConvertI32: {
-      LiftoffRegister scratch =
+      LiftoffRegister scratch = GetUnusedRegister(kFpReg, LiftoffRegList{dst});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dst));
      TurboAssembler::Cvt_d_uw(dst.fp(), src.gp(), scratch.fp());
      return true;
    }
@@ -1614,7 +1606,7 @@ void LiftoffAssembler::emit_i32_set_cond(LiftoffCondition liftoff_cond,
  Condition cond = liftoff::ToCondition(liftoff_cond);
  Register tmp = dst;
  if (dst == lhs || dst == rhs) {
-    tmp = GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(lhs, rhs)).gp();
+    tmp = GetUnusedRegister(kGpReg, LiftoffRegList{lhs, rhs}).gp();
  }
  // Write 1 as result.
  TurboAssembler::li(tmp, 1);
@@ -1628,8 +1620,7 @@ void LiftoffAssembler::emit_i32_set_cond(LiftoffCondition liftoff_cond,
 }
 void LiftoffAssembler::emit_i64_eqz(Register dst, LiftoffRegister src) {
-  Register tmp =
+  Register tmp = GetUnusedRegister(kGpReg, LiftoffRegList{src, dst}).gp();
-      GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(src, dst)).gp();
  sltiu(tmp, src.low_gp(), 1);
  sltiu(dst, src.high_gp(), 1);
  and_(dst, dst, tmp);
@@ -1666,8 +1657,7 @@ void LiftoffAssembler::emit_i64_set_cond(LiftoffCondition liftoff_cond,
  Register tmp = dst;
  if (liftoff::IsRegInRegPair(lhs, dst) || liftoff::IsRegInRegPair(rhs, dst)) {
-    tmp =
+    tmp = GetUnusedRegister(kGpReg, LiftoffRegList{dst, lhs, rhs}).gp();
-        GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(dst, lhs, rhs)).gp();
  }
  // Write 1 initially in tmp register.

--- a/src/wasm/baseline/mips64/liftoff-assembler-mips64.h
+++ b/src/wasm/baseline/mips64/liftoff-assembler-mips64.h
@@ -738,8 +738,7 @@ void LiftoffAssembler::AtomicStore(Register dst_addr, Register offset_reg,
  void LiftoffAssembler::Atomic##name(                                   \
      Register dst_addr, Register offset_reg, uintptr_t offset_imm,      \
      LiftoffRegister value, LiftoffRegister result, StoreType type) {   \
-    LiftoffRegList pinned =                                              \
+    LiftoffRegList pinned = {dst_addr, offset_reg, value, result};       \
-        LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result);    \
    Register temp0 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp(); \
    Register temp1 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp(); \
    Register temp2 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp(); \
@@ -816,8 +815,7 @@ void LiftoffAssembler::AtomicExchange(Register dst_addr, Register offset_reg,
                                      uintptr_t offset_imm,
                                      LiftoffRegister value,
                                      LiftoffRegister result, StoreType type) {
-  LiftoffRegList pinned =
+  LiftoffRegList pinned = {dst_addr, offset_reg, value, result};
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result);
  Register temp0 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp1 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp2 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
@@ -893,8 +891,7 @@ void LiftoffAssembler::AtomicCompareExchange(
    Register dst_addr, Register offset_reg, uintptr_t offset_imm,
    LiftoffRegister expected, LiftoffRegister new_value, LiftoffRegister result,
    StoreType type) {
-  LiftoffRegList pinned = LiftoffRegList::ForRegs(dst_addr, offset_reg,
+  LiftoffRegList pinned = {dst_addr, offset_reg, expected, new_value, result};
-                                                  expected, new_value, result);
  Register temp0 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp1 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
  Register temp2 = pinned.set(GetUnusedRegister(kGpReg, pinned)).gp();
@@ -1463,10 +1460,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      TurboAssembler::Ext(dst.gp(), src.gp(), 0, 32);
      return true;
    case kExprI32SConvertF32: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_s_s(rounded.fp(), src.fp());
@@ -1486,10 +1482,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI32UConvertF32: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_s_s(rounded.fp(), src.fp());
@@ -1507,10 +1502,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI32SConvertF64: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_d_d(rounded.fp(), src.fp());
@@ -1524,10 +1518,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI32UConvertF64: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_d_d(rounded.fp(), src.fp());
@@ -1549,10 +1542,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      TurboAssembler::Dext(dst.gp(), src.gp(), 0, 32);
      return true;
    case kExprI64SConvertF32: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_s_s(rounded.fp(), src.fp());
@@ -1581,10 +1573,9 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      return true;
    }
    case kExprI64SConvertF64: {
-      LiftoffRegister rounded =
+      LiftoffRegister rounded = GetUnusedRegister(kFpReg, LiftoffRegList{src});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src));
      LiftoffRegister converted_back =
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src, rounded));
+          GetUnusedRegister(kFpReg, LiftoffRegList{src, rounded});
      // Real conversion.
      TurboAssembler::Trunc_d_d(rounded.fp(), src.fp());
@@ -1616,8 +1607,7 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      dmfc1(dst.gp(), src.fp());
      return true;
    case kExprF32SConvertI32: {
-      LiftoffRegister scratch =
+      LiftoffRegister scratch = GetUnusedRegister(kFpReg, LiftoffRegList{dst});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dst));
      mtc1(src.gp(), scratch.fp());
      cvt_s_w(dst.fp(), scratch.fp());
      return true;
@@ -1632,8 +1622,7 @@ bool LiftoffAssembler::emit_type_conversion(WasmOpcode opcode,
      TurboAssembler::FmoveLow(dst.fp(), src.gp());
      return true;
    case kExprF64SConvertI32: {
-      LiftoffRegister scratch =
+      LiftoffRegister scratch = GetUnusedRegister(kFpReg, LiftoffRegList{dst});
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dst));
      mtc1(src.gp(), scratch.fp());
      cvt_d_w(dst.fp(), scratch.fp());
      return true;
@@ -1847,7 +1836,7 @@ void LiftoffAssembler::emit_i32_set_cond(LiftoffCondition liftoff_cond,
  Condition cond = liftoff::ToCondition(liftoff_cond);
  Register tmp = dst;
  if (dst == lhs || dst == rhs) {
-    tmp = GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(lhs, rhs)).gp();
+    tmp = GetUnusedRegister(kGpReg, LiftoffRegList{lhs, rhs}).gp();
  }
  // Write 1 as result.
  TurboAssembler::li(tmp, 1);
@@ -1870,7 +1859,7 @@ void LiftoffAssembler::emit_i64_set_cond(LiftoffCondition liftoff_cond,
  Condition cond = liftoff::ToCondition(liftoff_cond);
  Register tmp = dst;
  if (dst == lhs.gp() || dst == rhs.gp()) {
-    tmp = GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(lhs, rhs)).gp();
+    tmp = GetUnusedRegister(kGpReg, LiftoffRegList{lhs, rhs}).gp();
  }
  // Write 1 as result.
  TurboAssembler::li(tmp, 1);

--- a/src/wasm/baseline/riscv64/liftoff-assembler-riscv64.h
+++ b/src/wasm/baseline/riscv64/liftoff-assembler-riscv64.h
@@ -657,8 +657,7 @@ inline void AtomicBinop(LiftoffAssembler* lasm, Register dst_addr,
                        Register offset_reg, uintptr_t offset_imm,
                        LiftoffRegister value, LiftoffRegister result,
                        StoreType type, Binop op) {
-  LiftoffRegList pinned =
+  LiftoffRegList pinned = {dst_addr, offset_reg, value, result};
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result);
  Register store_result = pinned.set(__ GetUnusedRegister(kGpReg, pinned)).gp();
  // Make sure that {result} is unique.
@@ -869,8 +868,7 @@ void LiftoffAssembler::AtomicCompareExchange(
    Register dst_addr, Register offset_reg, uintptr_t offset_imm,
    LiftoffRegister expected, LiftoffRegister new_value, LiftoffRegister result,
    StoreType type) {
-  LiftoffRegList pinned =
+  LiftoffRegList pinned = {dst_addr, offset_reg, expected, new_value};
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, expected, new_value);
  Register result_reg = result.gp();
  if (pinned.has(result)) {
@@ -1866,7 +1864,7 @@ void LiftoffAssembler::emit_i8x16_shuffle(LiftoffRegister dst,
  VU.set(kScratchReg, E8, m1);
  VRegister temp =
-      GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(lhs, rhs)).fp().toV();
+      GetUnusedRegister(kFpReg, LiftoffRegList{lhs, rhs}).fp().toV();
  if (dst_v == lhs_v) {
    vmv_vv(temp, lhs_v);
    lhs_v = temp;

--- a/src/wasm/baseline/s390/liftoff-assembler-s390.h
+++ b/src/wasm/baseline/s390/liftoff-assembler-s390.h
@@ -561,13 +561,11 @@ void LiftoffAssembler::AtomicStore(Register dst_addr, Register offset_reg,
 void LiftoffAssembler::AtomicAdd(Register dst_addr, Register offset_reg,
                                 uintptr_t offset_imm, LiftoffRegister value,
                                 LiftoffRegister result, StoreType type) {
-  Register tmp1 =
+  Register tmp1 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(
+                                                           value, result})
-          kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result))
                      .gp();
-  Register tmp2 =
+  Register tmp2 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg,
+                                                           value, result, tmp1})
-                                                        value, result, tmp1))
                      .gp();
  if (!is_int20(offset_imm)) {
@@ -663,13 +661,11 @@ void LiftoffAssembler::AtomicAdd(Register dst_addr, Register offset_reg,
 void LiftoffAssembler::AtomicSub(Register dst_addr, Register offset_reg,
                                 uintptr_t offset_imm, LiftoffRegister value,
                                 LiftoffRegister result, StoreType type) {
-  Register tmp1 =
+  Register tmp1 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(
+                                                           value, result})
-          kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result))
                      .gp();
-  Register tmp2 =
+  Register tmp2 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg,
+                                                           value, result, tmp1})
-                                                        value, result, tmp1))
                      .gp();
  if (!is_int20(offset_imm)) {
@@ -765,13 +761,11 @@ void LiftoffAssembler::AtomicSub(Register dst_addr, Register offset_reg,
 void LiftoffAssembler::AtomicAnd(Register dst_addr, Register offset_reg,
                                 uintptr_t offset_imm, LiftoffRegister value,
                                 LiftoffRegister result, StoreType type) {
-  Register tmp1 =
+  Register tmp1 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(
+                                                           value, result})
-          kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result))
                      .gp();
-  Register tmp2 =
+  Register tmp2 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg,
+                                                           value, result, tmp1})
-                                                        value, result, tmp1))
                      .gp();
  if (!is_int20(offset_imm)) {
@@ -867,13 +861,11 @@ void LiftoffAssembler::AtomicAnd(Register dst_addr, Register offset_reg,
 void LiftoffAssembler::AtomicOr(Register dst_addr, Register offset_reg,
                                uintptr_t offset_imm, LiftoffRegister value,
                                LiftoffRegister result, StoreType type) {
-  Register tmp1 =
+  Register tmp1 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(
+                                                           value, result})
-          kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result))
                      .gp();
-  Register tmp2 =
+  Register tmp2 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg,
+                                                           value, result, tmp1})
-                                                        value, result, tmp1))
                      .gp();
  if (!is_int20(offset_imm)) {
@@ -969,13 +961,11 @@ void LiftoffAssembler::AtomicOr(Register dst_addr, Register offset_reg,
 void LiftoffAssembler::AtomicXor(Register dst_addr, Register offset_reg,
                                 uintptr_t offset_imm, LiftoffRegister value,
                                 LiftoffRegister result, StoreType type) {
-  Register tmp1 =
+  Register tmp1 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(
+                                                           value, result})
-          kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg, value, result))
                      .gp();
-  Register tmp2 =
+  Register tmp2 = GetUnusedRegister(kGpReg, LiftoffRegList{dst_addr, offset_reg,
-      GetUnusedRegister(kGpReg, LiftoffRegList::ForRegs(dst_addr, offset_reg,
+                                                           value, result, tmp1})
-                                                        value, result, tmp1))
                      .gp();
  if (!is_int20(offset_imm)) {
@@ -2532,12 +2522,10 @@ SIMD_ALL_TRUE_LIST(EMIT_SIMD_ALL_TRUE)
     * `EmitBinOp`. */                                                         \
    /* Make sure dst and temp are also unique. */                              \
    if (dest == src1 || dest == src2) {                                        \
-      dest =                                                                   \
+      dest = GetUnusedRegister(kFpReg, LiftoffRegList{src1, src2}).fp();       \
-          GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src1, src2)).fp(); \
    }                                                                          \
    Simd128Register temp =                                                     \
-        GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dest, src1, src2))   \
+        GetUnusedRegister(kFpReg, LiftoffRegList{dest, src1, src2}).fp();      \
-            .fp();                                                             \
    op(dest, src1, src2, kScratchDoubleReg, temp);                             \
    /* Original dst register needs to be populated. */                         \
    if (dest != dst.fp()) {                                                    \
@@ -2561,10 +2549,10 @@ SIMD_ADD_SUB_SAT_LIST(EMIT_SIMD_ADD_SUB_SAT)
    Simd128Register dest = dst.fp();                                 \
    /* Make sure dst and temp are unique. */                         \
    if (dest == src1) {                                              \
-      dest = GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(src1)).fp();  \
+      dest = GetUnusedRegister(kFpReg, LiftoffRegList{src1}).fp();   \
    }                                                                \
    Simd128Register temp =                                           \
-        GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dest, src1)).fp(); \
+        GetUnusedRegister(kFpReg, LiftoffRegList{dest, src1}).fp();  \
    op(dest, src1, kScratchDoubleReg, temp);                         \
    if (dest != dst.fp()) {                                          \
      vlr(dst.fp(), dest, Condition(0), Condition(0), Condition(0)); \
@@ -2716,7 +2704,7 @@ void LiftoffAssembler::emit_i8x16_swizzle(LiftoffRegister dst,
  Simd128Register src2 = rhs.fp();
  Simd128Register dest = dst.fp();
  Simd128Register temp =
-      GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dest, src1, src2)).fp();
+      GetUnusedRegister(kFpReg, LiftoffRegList{dest, src1, src2}).fp();
  I8x16Swizzle(dest, src1, src2, r0, r1, kScratchDoubleReg, temp);
 }
@@ -2764,10 +2752,9 @@ void LiftoffAssembler::emit_i16x8_q15mulr_sat_s(LiftoffRegister dst,
  Simd128Register dest = dst.fp();
  // Make sure temp registers are unique.
  Simd128Register temp1 =
-      GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dest, s1, s2)).fp();
+      GetUnusedRegister(kFpReg, LiftoffRegList{dest, s1, s2}).fp();
  Simd128Register temp2 =
-      GetUnusedRegister(kFpReg, LiftoffRegList::ForRegs(dest, s1, s2, temp1))
+      GetUnusedRegister(kFpReg, LiftoffRegList{dest, s1, s2, temp1}).fp();
-          .fp();
  I16x8Q15MulRSatS(dest, s1, s2, kScratchDoubleReg, temp1, temp2);
 }

--- a/src/wasm/baseline/x64/liftoff-assembler-x64.h
+++ b/src/wasm/baseline/x64/liftoff-assembler-x64.h
@@ -598,8 +598,8 @@ void LiftoffAssembler::AtomicAdd(Register dst_addr, Register offset_reg,
 void LiftoffAssembler::AtomicSub(Register dst_addr, Register offset_reg,
                                 uintptr_t offset_imm, LiftoffRegister value,
                                 LiftoffRegister result, StoreType type) {
-  LiftoffRegList dont_overwrite = cache_state()->used_registers |
+  LiftoffRegList dont_overwrite =
-                                  LiftoffRegList::ForRegs(dst_addr, offset_reg);
+      cache_state()->used_registers | LiftoffRegList{dst_addr, offset_reg};
  DCHECK(!dont_overwrite.has(result));
  if (dont_overwrite.has(value)) {
    // We cannot overwrite {value}, but the {value} register is changed in the
@@ -660,8 +660,7 @@ inline void AtomicBinop(LiftoffAssembler* lasm,
  // The cmpxchg instruction uses rax to store the old value of the
  // compare-exchange primitive. Therefore we have to spill the register and
  // move any use to another register.
-  LiftoffRegList pinned =
+  LiftoffRegList pinned = LiftoffRegList{dst_addr, offset_reg, value_reg};
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, value_reg);
  __ ClearRegister(rax, {&dst_addr, &offset_reg, &value_reg}, pinned);
  Operand dst_op = liftoff::GetMemOp(lasm, dst_addr, offset_reg, offset_imm);
@@ -798,7 +797,7 @@ void LiftoffAssembler::AtomicCompareExchange(
  // compare-exchange primitive. Therefore we have to spill the register and
  // move any use to another register.
  LiftoffRegList pinned =
-      LiftoffRegList::ForRegs(dst_addr, offset_reg, expected, value_reg);
+      LiftoffRegList{dst_addr, offset_reg, expected, value_reg};
  ClearRegister(rax, {&dst_addr, &offset_reg, &value_reg}, pinned);
  if (expected.gp() != rax) {
    movq(rax, expected.gp());
@@ -3429,9 +3428,9 @@ void LiftoffAssembler::emit_i64x2_mul(LiftoffRegister dst, LiftoffRegister lhs,
                                      LiftoffRegister rhs) {
  static constexpr RegClass tmp_rc = reg_class_for(kS128);
  LiftoffRegister tmp1 =
-      GetUnusedRegister(tmp_rc, LiftoffRegList::ForRegs(dst, lhs, rhs));
+      GetUnusedRegister(tmp_rc, LiftoffRegList{dst, lhs, rhs});
  LiftoffRegister tmp2 =
-      GetUnusedRegister(tmp_rc, LiftoffRegList::ForRegs(dst, lhs, rhs, tmp1));
+      GetUnusedRegister(tmp_rc, LiftoffRegList{dst, lhs, rhs, tmp1});
  I64x2Mul(dst.fp(), lhs.fp(), rhs.fp(), tmp1.fp(), tmp2.fp());
 }