[llvm] [X86][Codegen] - Introduce a new tuning for X86 backend to control FMA generation (PR #210343)

[Matt Arsenault via llvm-commits]

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@@ -3438,6 +3438,13 @@ class LLVM_ABI TargetLoweringBase {
     return false;
   }
 
+  /// When true, FMA fusion during DAG combine requires the FMUL to carry a
+  /// local contract flag, ignoring global -ffp-contract=fast.
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arsenm wrote:

The global fp-contract flag should not be used (didn't it get removed last year?) We definitely don't want to introduce new arbitrary target knobs like this to avoid using a flag that shouldn't exist in the first place 

https://github.com/llvm/llvm-project/pull/210343