[clang] [NFC][Driver] Clean up RenderFloatingPointOptions() (PR #91017)

[Andy Kaylor via cfe-commits]

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@@ -3010,13 +2995,8 @@ static void RenderFloatingPointOptions(const ToolChain &TC, const Driver &D,
     // Validate and pass through -ffp-contract option.
     case options::OPT_ffp_contract: {
       StringRef Val = A->getValue();
-      if (PreciseFPModel) {
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andykaylor wrote:

Near as I can tell, the only thing PreciseFPModel was still being used for was to allow us to detect that we had gotten here as a result of the OPT_ffp_model_EQ handler above changing the value of optID and falling through to the second `switch (optID)` statement, and the only effect it had was to keep us from setting LastSeenFfpContractOption. Since I am eliminating the fallthrough and the redundant switch statement, this value is no longer needed.

https://github.com/llvm/llvm-project/pull/91017