[llvm] CodeGen: Add ISD::AssertNoFPClass (PR #135946)

[Matt Arsenault via llvm-commits]

================
@@ -10,3 +10,13 @@ entry:
   %cond = tail call float @llvm.maximumnum.f32(float %a, float %b)
   ret float %cond
 }
+
+define <4 x float> @fv4f32(<4 x float> nofpclass(nan) %a, <4 x float> nofpclass(nan) %b) {
+; CHECK-LABEL: fv4f32:
+; CHECK:       // %bb.0: // %entry
+; CHECK-NEXT:    fmaxnm v0.4s, v0.4s, v1.4s
+; CHECK-NEXT:    ret
+entry:
+  %c = call <4 x float> @llvm.maximumnum.v4f32(<4 x float> %a, <4 x float> %b)
+  ret <4 x float> %c
+}
----------------
arsenm wrote:

also test aggregate case, e.g. 

```
define { float, float } @struct({ float, float } nofpclass(nan) %a) {
   ret {float, float} %a
 }
```

https://github.com/llvm/llvm-project/pull/135946