[WebAssembly] Fix inline assembly with vector types (#146574)

This commit fixes using inline assembly with v128 results. Previously
this failed with an internal assertion about a failure to legalize a
`CopyFromReg` where the source register was typed `v8f16`. It looks like
the type used for the destination register was whatever was listed first
in the `def V128 : WebAssemblyRegClass` listing, so the types were
shuffled around to have a default-supported type.

A small test was added as well which failed to generate previously and
should now pass in generation. This test passed on LLVM 18 additionally
and regressed by accident in #93228 which was first included in LLVM 19.

Author: alexcrichton

llvm/lib/Target/WebAssembly/WebAssemblyRegisterInfo.td

@@ -64,8 +64,8 @@ def I32 : WebAssemblyRegClass<[i32], 32, (add FP32, SP32, I32_0)>;
 def I64 : WebAssemblyRegClass<[i64], 64, (add FP64, SP64, I64_0)>;
 def F32 : WebAssemblyRegClass<[f32], 32, (add F32_0)>;
 def F64 : WebAssemblyRegClass<[f64], 64, (add F64_0)>;
-def V128 : WebAssemblyRegClass<[v8f16, v4f32, v2f64, v2i64, v4i32, v16i8,
-                                v8i16],
+def V128 : WebAssemblyRegClass<[v2i64, v4i32, v16i8, v8i16,
+                                v8f16, v4f32, v2f64],
                                128, (add V128_0)>;
 def FUNCREF : WebAssemblyRegClass<[funcref], 0, (add FUNCREF_0)>;
 def EXTERNREF : WebAssemblyRegClass<[externref], 0, (add EXTERNREF_0)>;

llvm/test/CodeGen/WebAssembly/inline-asm.ll

@@ -129,7 +129,18 @@ entry:
   ret i32 %ret
 }
 
+; CHECK-LABEL: v128_load
+; CHECK: local.get 0
+; CHECK-NEXT: v128.load 0
+; CHECK-NEXT: local.set 1
+define <4 x i32> @v128_load(ptr %v) #1 {
+entry:
+  %0 = tail call <4 x i32> asm "local.get $1\0Av128.load 0\0Alocal.set $0", "=r,r"(ptr %v)
+  ret <4 x i32> %0
+}
+
 attributes #0 = { nounwind }
+attributes #1 = { "target-features"="+simd128" }
 
 !0 = !{i32 47}
 !1 = !{i32 145}