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

[Rohit Aggarwal 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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rohitaggarwal007 wrote:


```llvm
bool AllowFusionGlobally =
      Options.AllowFPOpFusion == FPOpFusion::Fast || HasFMAD;
auto isContractableFMUL = [AllowFusionGlobally](SDValue N) {
    if (N.getOpcode() != ISD::FMUL)
      return false;
    return AllowFusionGlobally || N->getFlags().hasAllowContract();
  };
```
I didn't think so.  As the code snippet. Here AllowFusionGlobally is given first preference and then to the local contract. I am trying to give preference to local contract.

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