[llvm] Add PreLegalizer pattern matching for degrees GL extension (PR #216506)

[Kaitlin Peng via llvm-commits]

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@@ -381,3 +381,53 @@ void SPIRVCombinerHelper::applyMatrixMultiply(MachineInstr &MI) const {
     Builder.buildBuildVector(ResReg, ResultScalars);
   MI.eraseFromParent();
 }
+
+bool SPIRVCombinerHelper::matchDegrees(MachineInstr &MI) const {
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kmpeng wrote:

same nit on order

https://github.com/llvm/llvm-project/pull/216506