diff --git a/cranelift/fuzzgen/src/function_generator.rs b/cranelift/fuzzgen/src/function_generator.rs
index fd1dcd9dac3a..2ada0e869d72 100644
--- a/cranelift/fuzzgen/src/function_generator.rs
+++ b/cranelift/fuzzgen/src/function_generator.rs
@@ -1580,48 +1580,6 @@ const OPCODE_SIGNATURES: &[OpcodeSignature] = &[
     (Opcode::Bitcast, &[I32], &[F32]),
     (Opcode::Bitcast, &[F64], &[I64]),
     (Opcode::Bitcast, &[I64], &[F64]),
-    (Opcode::Bitcast, &[I128], &[I8X16]),
-    (Opcode::Bitcast, &[I128], &[I16X8]),
-    (Opcode::Bitcast, &[I128], &[I32X4]),
-    (Opcode::Bitcast, &[I128], &[I64X2]),
-    (Opcode::Bitcast, &[I128], &[F32X4]),
-    (Opcode::Bitcast, &[I128], &[F64X2]),
-    (Opcode::Bitcast, &[F32X4], &[I8X16]),
-    (Opcode::Bitcast, &[F32X4], &[I16X8]),
-    (Opcode::Bitcast, &[F32X4], &[I32X4]),
-    (Opcode::Bitcast, &[F32X4], &[I64X2]),
-    (Opcode::Bitcast, &[F32X4], &[F64X2]),
-    (Opcode::Bitcast, &[F32X4], &[I128]),
-    (Opcode::Bitcast, &[F64X2], &[I8X16]),
-    (Opcode::Bitcast, &[F64X2], &[I16X8]),
-    (Opcode::Bitcast, &[F64X2], &[I32X4]),
-    (Opcode::Bitcast, &[F64X2], &[I64X2]),
-    (Opcode::Bitcast, &[F64X2], &[F32X4]),
-    (Opcode::Bitcast, &[F64X2], &[I128]),
-    (Opcode::Bitcast, &[I8X16], &[I16X8]),
-    (Opcode::Bitcast, &[I8X16], &[I32X4]),
-    (Opcode::Bitcast, &[I8X16], &[I64X2]),
-    (Opcode::Bitcast, &[I8X16], &[F32X4]),
-    (Opcode::Bitcast, &[I8X16], &[F64X2]),
-    (Opcode::Bitcast, &[I8X16], &[I128]),
-    (Opcode::Bitcast, &[I16X8], &[I8X16]),
-    (Opcode::Bitcast, &[I16X8], &[I32X4]),
-    (Opcode::Bitcast, &[I16X8], &[I64X2]),
-    (Opcode::Bitcast, &[I16X8], &[F32X4]),
-    (Opcode::Bitcast, &[I16X8], &[F64X2]),
-    (Opcode::Bitcast, &[I16X8], &[I128]),
-    (Opcode::Bitcast, &[I32X4], &[I8X16]),
-    (Opcode::Bitcast, &[I32X4], &[I16X8]),
-    (Opcode::Bitcast, &[I32X4], &[I64X2]),
-    (Opcode::Bitcast, &[I32X4], &[F32X4]),
-    (Opcode::Bitcast, &[I32X4], &[F64X2]),
-    (Opcode::Bitcast, &[I32X4], &[I128]),
-    (Opcode::Bitcast, &[I64X2], &[I8X16]),
-    (Opcode::Bitcast, &[I64X2], &[I16X8]),
-    (Opcode::Bitcast, &[I64X2], &[I32X4]),
-    (Opcode::Bitcast, &[I64X2], &[F32X4]),
-    (Opcode::Bitcast, &[I64X2], &[F64X2]),
-    (Opcode::Bitcast, &[I64X2], &[I128]),
     // Shuffle
     (Opcode::Shuffle, &[I8X16, I8X16, I8X16], &[I8X16]),
     // Swizzle