llvm · sunfishcode · Oct 23, 2024 · Oct 8, 2024 · Oct 8, 2024 · Oct 8, 2024
diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td
@@ -5098,6 +5098,8 @@ def msimd128 : Flag<["-"], "msimd128">, Group<m_wasm_Features_Group>;
 def mno_simd128 : Flag<["-"], "mno-simd128">, Group<m_wasm_Features_Group>;
 def mtail_call : Flag<["-"], "mtail-call">, Group<m_wasm_Features_Group>;
 def mno_tail_call : Flag<["-"], "mno-tail-call">, Group<m_wasm_Features_Group>;
+def mwide_arithmetic : Flag<["-"], "mwide-arithmetic">, Group<m_wasm_Features_Group>;
+def mno_wide_arithmetic : Flag<["-"], "mno-wide-arithmetic">, Group<m_wasm_Features_Group>;
 def mexec_model_EQ : Joined<["-"], "mexec-model=">, Group<m_wasm_Features_Driver_Group>,
                      Values<"command,reactor">,
                      HelpText<"Execution model (WebAssembly only)">,

diff --git a/clang/lib/Basic/Targets/WebAssembly.cpp b/clang/lib/Basic/Targets/WebAssembly.cpp
@@ -59,6 +59,7 @@ bool WebAssemblyTargetInfo::hasFeature(StringRef Feature) const {
       .Case("sign-ext", HasSignExt)
       .Case("simd128", SIMDLevel >= SIMD128)
       .Case("tail-call", HasTailCall)
+      .Case("wide-arithmetic", HasWideArithmetic)
       .Default(false);
 }
 
@@ -102,6 +103,8 @@ void WebAssemblyTargetInfo::getTargetDefines(const LangOptions &Opts,
     Builder.defineMacro("__wasm_simd128__");
   if (HasTailCall)
     Builder.defineMacro("__wasm_tail_call__");
+  if (HasWideArithmetic)
+    Builder.defineMacro("__wasm_wide_arithmetic__");
 
   Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_1");
   Builder.defineMacro("__GCC_HAVE_SYNC_COMPARE_AND_SWAP_2");
@@ -166,6 +169,7 @@ bool WebAssemblyTargetInfo::initFeatureMap(
     Features["multimemory"] = true;
     Features["nontrapping-fptoint"] = true;
     Features["tail-call"] = true;
+    Features["wide-arithmetic"] = true;
     setSIMDLevel(Features, RelaxedSIMD, true);
   };
   if (CPU == "generic") {
@@ -293,6 +297,14 @@ bool WebAssemblyTargetInfo::handleTargetFeatures(
       HasTailCall = false;
       continue;
     }
+    if (Feature == "+wide-arithmetic") {
+      HasWideArithmetic = true;
+      continue;
+    }
+    if (Feature == "-wide-arithmetic") {
+      HasWideArithmetic = false;
+      continue;
+    }
 
     Diags.Report(diag::err_opt_not_valid_with_opt)
         << Feature << "-target-feature";

diff --git a/clang/lib/Basic/Targets/WebAssembly.h b/clang/lib/Basic/Targets/WebAssembly.h
@@ -65,6 +65,7 @@ class LLVM_LIBRARY_VISIBILITY WebAssemblyTargetInfo : public TargetInfo {
   bool HasReferenceTypes = false;
   bool HasSignExt = false;
   bool HasTailCall = false;
+  bool HasWideArithmetic = false;
 
   std::string ABI;
 

diff --git a/clang/test/Driver/wasm-features.c b/clang/test/Driver/wasm-features.c
@@ -94,3 +94,9 @@
 
 // TAIL-CALL: "-target-feature" "+tail-call"
 // NO-TAIL-CALL: "-target-feature" "-tail-call"
+
+// RUN: %clang --target=wasm32-unknown-unknown -### %s -mwide-arithmetic 2>&1 | FileCheck %s -check-prefix=WIDE-ARITH
+// RUN: %clang --target=wasm32-unknown-unknown -### %s -mno-wide-arithmetic 2>&1 | FileCheck %s -check-prefix=NO-WIDE-ARITH
+
+// WIDE-ARITH: "-target-feature" "+wide-arithmetic"
+// NO-WIDE-ARITH: "-target-feature" "-wide-arithmetic"
diff --git a/clang/test/Preprocessor/wasm-target-features.c b/clang/test/Preprocessor/wasm-target-features.c
@@ -154,6 +154,7 @@
 // MVP-NOT: #define __wasm_sign_ext__ 1{{$}}
 // MVP-NOT: #define __wasm_simd128__ 1{{$}}
 // MVP-NOT: #define __wasm_tail_call__ 1{{$}}
+// MVP-NOT: #define __wasm_wide_arithmetic__ 1{{$}}
 
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=generic \
@@ -184,6 +185,7 @@
 // GENERIC-NOT: #define __wasm_relaxed_simd__ 1{{$}}
 // GENERIC-NOT: #define __wasm_simd128__ 1{{$}}
 // GENERIC-NOT: #define __wasm_tail_call__ 1{{$}}
+// GENERIC-NOT: #define __wasm_wide_arithmetic__ 1{{$}}
 
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=bleeding-edge \
@@ -206,6 +208,7 @@
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_sign_ext__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_simd128__ 1{{$}}
 // BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_tail_call__ 1{{$}}
+// BLEEDING-EDGE-INCLUDE-DAG: #define __wasm_wide_arithmetic__ 1{{$}}
 
 // RUN: %clang -E -dM %s -o - 2>&1 \
 // RUN:     -target wasm32-unknown-unknown -mcpu=bleeding-edge -mno-simd128 \
@@ -215,3 +218,12 @@
 // RUN:   | FileCheck %s -check-prefix=BLEEDING-EDGE-NO-SIMD128
 //
 // BLEEDING-EDGE-NO-SIMD128-NOT: #define __wasm_simd128__ 1{{$}}
+
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm32-unknown-unknown -mwide-arithmetic \
+// RUN:   | FileCheck %s -check-prefix=WIDE-ARITHMETIC
+// RUN: %clang -E -dM %s -o - 2>&1 \
+// RUN:     -target wasm64-unknown-unknown -mwide-arithmetic \
+// RUN:   | FileCheck %s -check-prefix=WIDE-ARITHMETIC
+//
+// WIDE-ARITHMETIC: #define __wasm_wide_arithmetic__ 1{{$}}
diff --git a/llvm/lib/Target/WebAssembly/WebAssembly.td b/llvm/lib/Target/WebAssembly/WebAssembly.td
@@ -78,6 +78,10 @@ def FeatureTailCall :
       SubtargetFeature<"tail-call", "HasTailCall", "true",
                        "Enable tail call instructions">;
 
+def FeatureWideArithmetic :
+      SubtargetFeature<"wide-arithmetic", "HasWideArithmetic", "true",
+                       "Enable wide-arithmetic instructions">;
+
 //===----------------------------------------------------------------------===//
 // Architectures.
 //===----------------------------------------------------------------------===//

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISD.def b/llvm/lib/Target/WebAssembly/WebAssemblyISD.def
@@ -44,6 +44,10 @@ HANDLE_NODETYPE(TRUNC_SAT_ZERO_U)
 HANDLE_NODETYPE(DEMOTE_ZERO)
 HANDLE_NODETYPE(MEMORY_COPY)
 HANDLE_NODETYPE(MEMORY_FILL)
+HANDLE_NODETYPE(I64_ADD128)
+HANDLE_NODETYPE(I64_SUB128)
+HANDLE_NODETYPE(I64_MUL_WIDE_S)
+HANDLE_NODETYPE(I64_MUL_WIDE_U)
 
 // Memory intrinsics
 HANDLE_MEM_NODETYPE(GLOBAL_GET)

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -167,6 +167,13 @@ WebAssemblyTargetLowering::WebAssemblyTargetLowering(
         setOperationAction(Op, T, Expand);
   }
 
+  if (Subtarget->hasWideArithmetic()) {
+    setOperationAction(ISD::ADD, MVT::i128, Custom);
+    setOperationAction(ISD::SUB, MVT::i128, Custom);
+    setOperationAction(ISD::SMUL_LOHI, MVT::i64, Custom);
+    setOperationAction(ISD::UMUL_LOHI, MVT::i64, Custom);
+  }
+
   if (Subtarget->hasNontrappingFPToInt())
     for (auto Op : {ISD::FP_TO_SINT_SAT, ISD::FP_TO_UINT_SAT})
       for (auto T : {MVT::i32, MVT::i64})
@@ -1443,6 +1450,10 @@ void WebAssemblyTargetLowering::ReplaceNodeResults(
     // Do not add any results, signifying that N should not be custom lowered.
     // EXTEND_VECTOR_INREG is implemented for some vectors, but not all.
     break;
+  case ISD::ADD:
+  case ISD::SUB:
+    Results.push_back(Replace128Op(N, DAG));
+    break;
   default:
     llvm_unreachable(
         "ReplaceNodeResults not implemented for this op for WebAssembly!");
@@ -1519,6 +1530,9 @@ SDValue WebAssemblyTargetLowering::LowerOperation(SDValue Op,
     return DAG.UnrollVectorOp(Op.getNode());
   case ISD::CLEAR_CACHE:
     report_fatal_error("llvm.clear_cache is not supported on wasm");
+  case ISD::SMUL_LOHI:
+  case ISD::UMUL_LOHI:
+    return LowerMUL_LOHI(Op, DAG);
   }
 }
 
@@ -1617,6 +1631,63 @@ SDValue WebAssemblyTargetLowering::LowerLoad(SDValue Op,
   return Op;
 }
 
+SDValue WebAssemblyTargetLowering::LowerMUL_LOHI(SDValue Op,
+                                                 SelectionDAG &DAG) const {
+  assert(Subtarget->hasWideArithmetic());
+  assert(Op.getValueType() == MVT::i64);
+  SDLoc DL(Op);
+  unsigned Opcode;
+  switch (Op.getOpcode()) {
+  case ISD::UMUL_LOHI:
+    Opcode = WebAssemblyISD::I64_MUL_WIDE_U;
+    break;
+  case ISD::SMUL_LOHI:
+    Opcode = WebAssemblyISD::I64_MUL_WIDE_S;
+    break;
+  default:
+    llvm_unreachable("unexpected opcode");
+  }
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+  SDValue Hi =
+      DAG.getNode(Opcode, DL, DAG.getVTList(MVT::i64, MVT::i64), LHS, RHS);
+  SDValue Lo(Hi.getNode(), 1);
+  SDValue Ops[] = {Hi, Lo};
+  return DAG.getMergeValues(Ops, DL);
+}
+
+SDValue WebAssemblyTargetLowering::Replace128Op(SDNode *N,
+                                                SelectionDAG &DAG) const {
+  assert(Subtarget->hasWideArithmetic());
+  auto ValTy = N->getValueType(0);
+  assert(ValTy == MVT::i128);
+  SDLoc DL(N);
+  unsigned Opcode;
+  switch (N->getOpcode()) {
+  case ISD::ADD:
+    Opcode = WebAssemblyISD::I64_ADD128;
+    break;
+  case ISD::SUB:
+    Opcode = WebAssemblyISD::I64_SUB128;
+    break;
+  default:
+    llvm_unreachable("unexpected opcode");
+  }
+  SDValue LHS = N->getOperand(0);
+  SDValue RHS = N->getOperand(1);
+
+  SDValue C0 = DAG.getConstant(0, DL, MVT::i64);
+  SDValue C1 = DAG.getConstant(1, DL, MVT::i64);
+  SDValue LHS_0 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i64, LHS, C0);
+  SDValue LHS_1 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i64, LHS, C1);
+  SDValue RHS_0 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i64, RHS, C0);
+  SDValue RHS_1 = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, MVT::i64, RHS, C1);
+  SDValue Result_LO = DAG.getNode(Opcode, DL, DAG.getVTList(MVT::i64, MVT::i64),
+                                  LHS_0, LHS_1, RHS_0, RHS_1);
+  SDValue Result_HI(Result_LO.getNode(), 1);
+  return DAG.getNode(ISD::BUILD_PAIR, DL, N->getVTList(), Result_LO, Result_HI);
+}
+
 SDValue WebAssemblyTargetLowering::LowerCopyToReg(SDValue Op,
                                                   SelectionDAG &DAG) const {
   SDValue Src = Op.getOperand(2);

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.h
@@ -138,6 +138,8 @@ class WebAssemblyTargetLowering final : public TargetLowering {
   SDValue LowerFP_TO_INT_SAT(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerLoad(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerStore(SDValue Op, SelectionDAG &DAG) const;
+  SDValue LowerMUL_LOHI(SDValue Op, SelectionDAG &DAG) const;
+  SDValue Replace128Op(SDNode *N, SelectionDAG &DAG) const;
 
   // Custom DAG combine hooks
   SDValue

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInfo.td
@@ -84,6 +84,10 @@ def HasTailCall :
     Predicate<"Subtarget->hasTailCall()">,
     AssemblerPredicate<(all_of FeatureTailCall), "tail-call">;
 
+def HasWideArithmetic :
+    Predicate<"Subtarget->hasWideArithmetic()">,
+    AssemblerPredicate<(all_of FeatureWideArithmetic), "wide-arithmetic">;
+
 //===----------------------------------------------------------------------===//
 // WebAssembly-specific DAG Node Types.
 //===----------------------------------------------------------------------===//

diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyInstrInteger.td b/llvm/lib/Target/WebAssembly/WebAssemblyInstrInteger.td
@@ -129,3 +129,48 @@ def : Pat<(select (i32 (seteq I32:$cond, 0)), I32:$lhs, I32:$rhs),
           (SELECT_I32 I32:$rhs, I32:$lhs, I32:$cond)>;
 def : Pat<(select (i32 (seteq I32:$cond, 0)), I64:$lhs, I64:$rhs),
           (SELECT_I64 I64:$rhs, I64:$lhs, I32:$cond)>;
+
+let Predicates = [HasWideArithmetic] in {
+defm I64_ADD128 : I<(outs I64:$lo, I64:$hi), (ins I64:$lhs_lo, I64:$lhs_hi, I64:$rhs_lo, I64:$rhs_hi),
+                    (outs), (ins),
+                    [],
+                     "i64.add128\t$lo, $hi, $lhs_lo, $lhs_hi, $rhs_lo, $rhs_hi",
+                     "i64.add128",
+                     0xfc13>;
+defm I64_SUB128 : I<(outs I64:$lo, I64:$hi), (ins I64:$lhs_lo, I64:$lhs_hi, I64:$rhs_lo, I64:$rhs_hi),
+                    (outs), (ins),
+                    [],
+                     "i64.sub128\t$lo, $hi, $lhs_lo, $lhs_hi, $rhs_lo, $rhs_hi",
+                     "i64.sub128",
+                     0xfc14>;
+defm I64_MUL_WIDE_S : I<(outs I64:$lo, I64:$hi), (ins I64:$lhs, I64:$rhs),
+                        (outs), (ins),
+                        [],
+                         "i64.mul_wide_s\t$lo, $hi, $lhs, $rhs",
+                         "i64.mul_wide_s",
+                         0xfc15>;
+defm I64_MUL_WIDE_U : I<(outs I64:$lo, I64:$hi), (ins I64:$lhs, I64:$rhs),
+                        (outs), (ins),
+                        [],
+                        "i64.mul_wide_u\t$lo, $hi, $lhs, $rhs",
+                        "i64.mul_wide_u",
+                        0xfc16>;
+} // Predicates = [HasWideArithmetic]
+
+def wasm_binop128_t : SDTypeProfile<2, 4, []>;
+def wasm_add128 : SDNode<"WebAssemblyISD::I64_ADD128", wasm_binop128_t>;
+def wasm_sub128 : SDNode<"WebAssemblyISD::I64_SUB128", wasm_binop128_t>;
+
+def : Pat<(wasm_add128 I64:$a, I64:$b, I64:$c, I64:$d),
+          (I64_ADD128 $a, $b, $c, $d)>;
+def : Pat<(wasm_sub128 I64:$a, I64:$b, I64:$c, I64:$d),
+          (I64_SUB128 $a, $b, $c, $d)>;
+
+def wasm_mul_wide_t : SDTypeProfile<2, 2, []>;
+def wasm_mul_wide_s : SDNode<"WebAssemblyISD::I64_MUL_WIDE_S", wasm_mul_wide_t>;
+def wasm_mul_wide_u : SDNode<"WebAssemblyISD::I64_MUL_WIDE_U", wasm_mul_wide_t>;
+
+def : Pat<(wasm_mul_wide_s I64:$x, I64:$y),
+          (I64_MUL_WIDE_S $x, $y)>;
+def : Pat<(wasm_mul_wide_u I64:$x, I64:$y),
+          (I64_MUL_WIDE_U $x, $y)>;
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblySubtarget.h b/llvm/lib/Target/WebAssembly/WebAssemblySubtarget.h
@@ -51,6 +51,7 @@ class WebAssemblySubtarget final : public WebAssemblyGenSubtargetInfo {
   bool HasReferenceTypes = false;
   bool HasSignExt = false;
   bool HasTailCall = false;
+  bool HasWideArithmetic = false;
 
   /// What processor and OS we're targeting.
   Triple TargetTriple;
@@ -106,6 +107,7 @@ class WebAssemblySubtarget final : public WebAssemblyGenSubtargetInfo {
   bool hasSignExt() const { return HasSignExt; }
   bool hasSIMD128() const { return SIMDLevel >= SIMD128; }
   bool hasTailCall() const { return HasTailCall; }
+  bool hasWideArithmetic() const { return HasWideArithmetic; }
 
   /// Parses features string setting specified subtarget options. Definition of
   /// function is auto generated by tblgen.

diff --git a/llvm/test/CodeGen/WebAssembly/wide-arithmetic.ll b/llvm/test/CodeGen/WebAssembly/wide-arithmetic.ll
@@ -0,0 +1,132 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mattr=+wide-arithmetic < %s | FileCheck %s
+
+target triple = "wasm32-unknown-unknown"
+
+define i128 @add_i128(i128 %a, i128 %b) {
+; CHECK-LABEL: add_i128:
+; CHECK:         .functype add_i128 (i32, i64, i64, i64, i64) -> ()
+; CHECK-NEXT:  # %bb.0:
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    local.get 2
+; CHECK-NEXT:    local.get 3
+; CHECK-NEXT:    local.get 4
+; CHECK-NEXT:    i64.add128
+; CHECK-NEXT:    local.set 3
+; CHECK-NEXT:    local.set 4
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 3
+; CHECK-NEXT:    i64.store 8
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 4
+; CHECK-NEXT:    i64.store 0
+; CHECK-NEXT:    # fallthrough-return
+  %c = add i128 %a, %b
+  ret i128 %c
+}
+
+define i128 @sub_i128(i128 %a, i128 %b) {
+; CHECK-LABEL: sub_i128:
+; CHECK:         .functype sub_i128 (i32, i64, i64, i64, i64) -> ()
+; CHECK-NEXT:  # %bb.0:
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    local.get 2
+; CHECK-NEXT:    local.get 3
+; CHECK-NEXT:    local.get 4
+; CHECK-NEXT:    i64.sub128
+; CHECK-NEXT:    local.set 3
+; CHECK-NEXT:    local.set 4
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 3
+; CHECK-NEXT:    i64.store 8
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 4
+; CHECK-NEXT:    i64.store 0
+; CHECK-NEXT:    # fallthrough-return
+  %c = sub i128 %a, %b
+  ret i128 %c
+}
+
+define i128 @mul_i128(i128 %a, i128 %b) {
+; CHECK-LABEL: mul_i128:
+; CHECK:         .functype mul_i128 (i32, i64, i64, i64, i64) -> ()
+; CHECK-NEXT:    .local i64
+; CHECK-NEXT:  # %bb.0:
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    local.get 3
+; CHECK-NEXT:    i64.mul_wide_u
+; CHECK-NEXT:    local.set 5
+; CHECK-NEXT:    i64.store 0
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 5
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    local.get 4
+; CHECK-NEXT:    i64.mul
+; CHECK-NEXT:    i64.add
+; CHECK-NEXT:    local.get 2
+; CHECK-NEXT:    local.get 3
+; CHECK-NEXT:    i64.mul
+; CHECK-NEXT:    i64.add
+; CHECK-NEXT:    i64.store 8
+; CHECK-NEXT:    # fallthrough-return
+  %c = mul i128 %a, %b
+  ret i128 %c
+}
+
+define i128 @i64_mul_wide_s(i64 %a, i64 %b) {
+; CHECK-LABEL: i64_mul_wide_s:
+; CHECK:         .functype i64_mul_wide_s (i32, i64, i64) -> ()
+; CHECK-NEXT:  # %bb.0:
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    local.get 2
+; CHECK-NEXT:    i64.mul_wide_s
+; CHECK-NEXT:    local.set 1
+; CHECK-NEXT:    local.set 2
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    i64.store 8
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 2
+; CHECK-NEXT:    i64.store 0
+; CHECK-NEXT:    # fallthrough-return
+  %a128 = sext i64 %a to i128
+  %b128 = sext i64 %b to i128
+  %c = mul i128 %a128, %b128
+  ret i128 %c
+}
+
+define i128 @i64_mul_wide_u(i64 %a, i64 %b) {
+; CHECK-LABEL: i64_mul_wide_u:
+; CHECK:         .functype i64_mul_wide_u (i32, i64, i64) -> ()
+; CHECK-NEXT:  # %bb.0:
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    local.get 2
+; CHECK-NEXT:    i64.mul_wide_u
+; CHECK-NEXT:    local.set 1
+; CHECK-NEXT:    local.set 2
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 1
+; CHECK-NEXT:    i64.store 8
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 2
+; CHECK-NEXT:    i64.store 0
+; CHECK-NEXT:    # fallthrough-return
+  %a128 = zext i64 %a to i128
+  %b128 = zext i64 %b to i128
+  %c = mul i128 %a128, %b128
+  ret i128 %c
+}
+
+define i64 @mul_i128_only_lo(i128 %a, i128 %b) {
+; CHECK-LABEL: mul_i128_only_lo:
+; CHECK:         .functype mul_i128_only_lo (i64, i64, i64, i64) -> (i64)
+; CHECK-NEXT:  # %bb.0:
+; CHECK-NEXT:    local.get 0
+; CHECK-NEXT:    local.get 2
+; CHECK-NEXT:    i64.mul
+; CHECK-NEXT:    # fallthrough-return
+  %c = mul i128 %a, %b
+  %d = trunc i128 %c to i64
+  ret i64 %d
+}