[WebAssembly] Add simd128-unimplemented subtarget feature

This is a second attempt at r350778, which was reverted in
r350789. The only change is that the unimplemented-simd128 feature has
been renamed simd128-unimplemented, since naming it
unimplemented-simd128 somehow made the simd128 feature flag enable the
unimplemented-simd128 feature on Windows.

llvm-svn: 350791
diff --git a/llvm/test/CodeGen/WebAssembly/simd-bitcasts.ll b/llvm/test/CodeGen/WebAssembly/simd-bitcasts.ll
index f143720..0f04cae 100644
--- a/llvm/test/CodeGen/WebAssembly/simd-bitcasts.ll
+++ b/llvm/test/CodeGen/WebAssembly/simd-bitcasts.ll
@@ -1,6 +1,6 @@
-; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt -wasm-keep-registers -wasm-disable-explicit-locals -wasm-enable-unimplemented-simd -mattr=+simd128,+sign-ext | FileCheck %s --check-prefixes CHECK,SIMD128
-; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt -wasm-keep-registers -wasm-disable-explicit-locals -mattr=+simd128,+sign-ext | FileCheck %s --check-prefixes CHECK,SIMD128-VM
-; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt -wasm-keep-registers -wasm-disable-explicit-locals -mattr=-simd128,+sign-ext | FileCheck %s --check-prefixes CHECK,NO-SIMD128
+; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt -wasm-keep-registers -wasm-disable-explicit-locals -mattr=+simd128-unimplemented | FileCheck %s --check-prefixes CHECK,SIMD128
+; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt -wasm-keep-registers -wasm-disable-explicit-locals -mattr=+simd128 | FileCheck %s --check-prefixes CHECK,SIMD128-VM
+; RUN: llc < %s -asm-verbose=false -verify-machineinstrs -disable-wasm-fallthrough-return-opt -wasm-keep-registers -wasm-disable-explicit-locals | FileCheck %s --check-prefixes CHECK,NO-SIMD128
 
 ; Test that bitcasts between vector types are lowered to zero instructions