[clang] [NFC] Add assertion to ensure FiniteMathOnly is in sync with HonorINFs and HonorNANs. (PR #97342)

[Aaron Ballman via cfe-commits]

================
@@ -816,6 +816,11 @@ class FPOptions {
     setAllowFPReassociate(LO.AllowFPReassoc);
     setNoHonorNaNs(LO.NoHonorNaNs);
     setNoHonorInfs(LO.NoHonorInfs);
+    // Ensure that if FiniteMathOnly is enabled, NoHonorNaNs and NoHonorInfs are
+    // also enabled. This is because FiniteMathOnly mode assumes no NaNs or Infs
+    // are present in computations.
+    if (!LO.NoHonorInfs || !LO.NoHonorInfs)
+      assert(!LO.FiniteMathOnly && "FiniteMathOnly implies NoHonorInfs");
----------------
AaronBallman wrote:

How about:
```
assert((LO.FiniteMathOnly == (LO.NoHonorInfs && LO.NoHonorNans)) && "inf/nan inconsistent internal state");
```
to make it more clear that the state has to be sane no matter which options are set? Also, this corrects the duplicate condition in your `if` statement.

https://github.com/llvm/llvm-project/pull/97342