[clang] [llvm] [X86] Enable HasFastHalfType to prevent FP16 promotion and perform FABS/FNEG lowering (PR #189395)

[Tharun V K via cfe-commits]

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@@ -471,6 +471,8 @@ bool X86TargetInfo::handleTargetFeatures(std::vector<std::string> &Features,
     SSELevel = std::max(SSELevel, Level);
 
     HasFloat16 = SSELevel >= SSE2;
+    if (HasFloat16)
+      HasFastHalfType = true;
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tharunvk wrote:

Yes I agree other fp insts like fadd will be impacted. So I have removed this logic and handled fabs and fneg case separately in SelectionDAG LowerFP_ROUND

https://github.com/llvm/llvm-project/pull/189395