diff --git a/cranelift/codegen/src/isa/aarch64/inst.isle b/cranelift/codegen/src/isa/aarch64/inst.isle
index 68dd824634..a24620ee40 100644
--- a/cranelift/codegen/src/isa/aarch64/inst.isle
+++ b/cranelift/codegen/src/isa/aarch64/inst.isle
@@ -1731,6 +1731,13 @@
 (decl writable_zero_reg () WritableReg)
 (extern constructor writable_zero_reg writable_zero_reg)
 
+(decl value_regs_zero () ValueRegs)
+(rule (value_regs_zero)
+      (value_regs
+            (imm $I64 (ImmExtend.Zero) 0)
+            (imm $I64 (ImmExtend.Zero) 0)))
+
+
 ;; Helper for emitting `MInst.Mov` instructions.
 (decl mov (Reg Type) Reg)
 (rule (mov src ty)
@@ -2286,6 +2293,24 @@
 (decl sub_vec (Reg Reg VectorSize) Reg)
 (rule (sub_vec x y size) (vec_rrr (VecALUOp.Sub) x y size))
 
+(decl sub_i128 (ValueRegs ValueRegs) ValueRegs)
+(rule (sub_i128 x y)
+      (let
+          ;; Get the high/low registers for `x`.
+          ((x_regs ValueRegs x)
+           (x_lo Reg (value_regs_get x_regs 0))
+           (x_hi Reg (value_regs_get x_regs 1))
+
+           ;; Get the high/low registers for `y`.
+           (y_regs ValueRegs y)
+           (y_lo Reg (value_regs_get y_regs 0))
+           (y_hi Reg (value_regs_get y_regs 1)))
+        ;; the actual subtraction is `subs` followed by `sbc` which comprises
+        ;; the low/high bits of the result
+        (with_flags
+          (sub_with_flags_paired $I64 x_lo y_lo)
+          (sbc_paired $I64 x_hi y_hi))))
+
 ;; Helpers for generating `madd` instructions.
 
 (decl madd (Type Reg Reg Reg) Reg)
diff --git a/cranelift/codegen/src/isa/aarch64/lower.isle b/cranelift/codegen/src/isa/aarch64/lower.isle
index 464cf6f7aa..2900c67b99 100644
--- a/cranelift/codegen/src/isa/aarch64/lower.isle
+++ b/cranelift/codegen/src/isa/aarch64/lower.isle
@@ -540,21 +540,7 @@
 
 ;; `i128`
 (rule -1 (lower (has_type $I128 (isub x y)))
-      (let
-          ;; Get the high/low registers for `x`.
-          ((x_regs ValueRegs x)
-           (x_lo Reg (value_regs_get x_regs 0))
-           (x_hi Reg (value_regs_get x_regs 1))
-
-           ;; Get the high/low registers for `y`.
-           (y_regs ValueRegs y)
-           (y_lo Reg (value_regs_get y_regs 0))
-           (y_hi Reg (value_regs_get y_regs 1)))
-        ;; the actual subtraction is `subs` followed by `sbc` which comprises
-        ;; the low/high bits of the result
-        (with_flags
-          (sub_with_flags_paired $I64 x_lo y_lo)
-          (sbc_paired $I64 x_hi y_hi))))
+      (sub_i128 x y))
 
 ;;;; Rules for `uadd_sat` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
@@ -582,6 +568,10 @@
 (rule 1 (lower (has_type (fits_in_64 ty) (ineg x)))
       (sub ty (zero_reg) x))
 
+;; `i128`
+(rule 2 (lower (has_type $I128 (ineg x)))  
+      (sub_i128 (value_regs_zero) x))
+
 ;; vectors.
 (rule (lower (has_type (ty_vec128 ty) (ineg x)))
       (neg x (vector_size ty)))
diff --git a/cranelift/codegen/src/isa/riscv64/inst.isle b/cranelift/codegen/src/isa/riscv64/inst.isle
index 69ae36a904..7720facf54 100644
--- a/cranelift/codegen/src/isa/riscv64/inst.isle
+++ b/cranelift/codegen/src/isa/riscv64/inst.isle
@@ -703,6 +703,10 @@
 (decl zero_reg () Reg)
 (extern constructor zero_reg zero_reg)
 
+(decl value_regs_zero () ValueRegs)
+(rule (value_regs_zero)
+  (value_regs (imm $I64 0) (imm $I64 0)))
+
 (decl gen_float_round (FloatRoundOP Reg Type) Reg)
 (rule
   (gen_float_round op rs ty)
diff --git a/cranelift/codegen/src/isa/riscv64/lower.isle b/cranelift/codegen/src/isa/riscv64/lower.isle
index a24f05fc13..62f3b03acc 100644
--- a/cranelift/codegen/src/isa/riscv64/lower.isle
+++ b/cranelift/codegen/src/isa/riscv64/lower.isle
@@ -71,9 +71,11 @@
 ;;;; Rules for `ineg` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 ;; `i64` and smaller.
-(rule (lower (has_type (fits_in_64 ty) (ineg x)))
+(rule 1 (lower (has_type (fits_in_64 ty) (ineg x)))
   (alu_rrr (AluOPRRR.Sub) (zero_reg) x))
 
+(rule 2 (lower (has_type $I128 (ineg x)))
+  (i128_sub (value_regs_zero) x))
 
 ;;;; Rules for `imul` ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
diff --git a/cranelift/codegen/src/isa/x64/inst.isle b/cranelift/codegen/src/isa/x64/inst.isle
index da70f52409..e9b0b4ea45 100644
--- a/cranelift/codegen/src/isa/x64/inst.isle
+++ b/cranelift/codegen/src/isa/x64/inst.isle
@@ -2917,6 +2917,14 @@
             (size OperandSize (operand_size_of_type_32_64 ty))
             (_ Unit (emit (MInst.Neg size src dst))))
         dst))
+        
+;; Helper for creating `neg` instructions whose flags are also used.
+(decl x64_neg_paired (Type Gpr) ProducesFlags)
+(rule (x64_neg_paired ty src)
+      (let ((dst WritableGpr (temp_writable_gpr))
+            (size OperandSize (operand_size_of_type_32_64 ty))
+            (inst MInst (MInst.Neg size src dst)))
+        (ProducesFlags.ProducesFlagsReturnsResultWithConsumer inst dst)))
 
 (decl x64_lea (SyntheticAmode) Gpr)
 (rule (x64_lea addr)
diff --git a/cranelift/codegen/src/isa/x64/lower.isle b/cranelift/codegen/src/isa/x64/lower.isle
index 0c2267225e..5ff32deb1e 100644
--- a/cranelift/codegen/src/isa/x64/lower.isle
+++ b/cranelift/codegen/src/isa/x64/lower.isle
@@ -777,6 +777,15 @@
 (rule -1 (lower (has_type (fits_in_64 ty) (ineg x)))
       (x64_neg ty x))
 
+(rule -2 (lower (has_type $I128 (ineg x)))
+      ;; Get the high/low registers for `x`.
+      (let ((regs ValueRegs x)
+            (lo Gpr (value_regs_get_gpr regs 0))
+            (hi Gpr (value_regs_get_gpr regs 1)))
+        ;; Do a neg followed by an sub-with-borrow.
+        (with_flags (x64_neg_paired $I64 lo)
+                    (x64_sbb_paired $I64 (imm $I64 0) hi))))
+
 ;; SSE.
 
 (rule (lower (has_type $I8X16 (ineg x)))
diff --git a/cranelift/filetests/filetests/runtests/i128-ineg.clif b/cranelift/filetests/filetests/runtests/i128-ineg.clif
new file mode 100644
index 0000000000..4e50093c1c
--- /dev/null
+++ b/cranelift/filetests/filetests/runtests/i128-ineg.clif
@@ -0,0 +1,19 @@
+test interpret
+test run
+set enable_llvm_abi_extensions=true
+target aarch64
+target s390x
+target x86_64
+target riscv64
+
+function %ineg_i128(i128) -> i128 {
+block0(v0: i128):
+  v1 = ineg.i128 v0
+  return v1
+}
+; run: %ineg_i128(0) == 0
+; run: %ineg_i128(1) == -1
+; run: %ineg_i128(-1) == 1
+; run: %ineg_i128(2) == -2
+; run: %ineg_i128(0x80000000_00000000_00000000_00000000) == 0x80000000_00000000_00000000_00000000
+; run: %ineg_i128(0x7fffffff_ffffffff_ffffffff_ffffffff) == 0x80000000_00000000_00000000_00000001
diff --git a/cranelift/filetests/filetests/runtests/ineg.clif b/cranelift/filetests/filetests/runtests/ineg.clif
new file mode 100644
index 0000000000..00f1574d14
--- /dev/null
+++ b/cranelift/filetests/filetests/runtests/ineg.clif
@@ -0,0 +1,54 @@
+test interpret
+test run
+target aarch64
+target s390x
+target x86_64
+target riscv64
+
+function %ineg_i8(i8) -> i8 {
+block0(v0: i8):
+  v1 = ineg.i8 v0
+  return v1
+}
+; run: %ineg_i8(0) == 0
+; run: %ineg_i8(1) == -1
+; run: %ineg_i8(-1) == 1
+; run: %ineg_i8(2) == -2
+; run: %ineg_i8(0x80) == 0x80
+; run: %ineg_i8(0x7f) == 0x81
+
+function %ineg_i16(i16) -> i16 {
+block0(v0: i16):
+  v1 = ineg.i16 v0
+  return v1
+}
+; run: %ineg_i16(0) == 0
+; run: %ineg_i16(1) == -1
+; run: %ineg_i16(-1) == 1
+; run: %ineg_i16(2) == -2
+; run: %ineg_i16(0x8000) == 0x8000
+; run: %ineg_i16(0x7fff) == 0x8001
+
+function %ineg_i32(i32) -> i32 {
+block0(v0: i32):
+  v1 = ineg.i32 v0
+  return v1
+}
+; run: %ineg_i32(0) == 0
+; run: %ineg_i32(1) == -1
+; run: %ineg_i32(-1) == 1
+; run: %ineg_i32(2) == -2
+; run: %ineg_i32(0x80000000) == 0x80000000
+; run: %ineg_i32(0x7fffffff) == 0x80000001
+
+function %ineg_i64(i64) -> i64 {
+block0(v0: i64):
+  v1 = ineg.i64 v0
+  return v1
+}
+; run: %ineg_i64(0) == 0
+; run: %ineg_i64(1) == -1
+; run: %ineg_i64(-1) == 1
+; run: %ineg_i64(2) == -2
+; run: %ineg_i64(0x80000000_00000000) == 0x80000000_00000000
+; run: %ineg_i64(0x7fffffff_ffffffff) == 0x80000000_00000001
diff --git a/cranelift/fuzzgen/src/function_generator.rs b/cranelift/fuzzgen/src/function_generator.rs
index 88e0f62efc..825b73c02c 100644
--- a/cranelift/fuzzgen/src/function_generator.rs
+++ b/cranelift/fuzzgen/src/function_generator.rs
@@ -282,10 +282,6 @@ const OPCODE_SIGNATURES: &'static [(
     (Opcode::Ineg, &[I16, I16], &[I16], insert_opcode),
     (Opcode::Ineg, &[I32, I32], &[I32], insert_opcode),
     (Opcode::Ineg, &[I64, I64], &[I64], insert_opcode),
-    // ineg.i128 not implemented in some backends:
-    //   x64: https://github.com/bytecodealliance/wasmtime/issues/5105
-    //   aarch64: https://github.com/bytecodealliance/wasmtime/issues/5108
-    #[cfg(not(any(target_arch = "x86_64", target_arch = "aarch64")))]
     (Opcode::Ineg, &[I128, I128], &[I128], insert_opcode),
     // Imin
     // imin not implemented in some backends: