[llvm] AMDGPU/GlobalISel: add RegBankLegalize rules for bitfield extract (PR #132381)

[Matt Arsenault via llvm-commits]

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@@ -127,6 +131,120 @@ void RegBankLegalizeHelper::widenLoad(MachineInstr &MI, LLT WideTy,
   MI.eraseFromParent();
 }
 
+bool isSignedBFE(MachineInstr &MI) {
+  if (isa<GIntrinsic>(MI)) {
+    switch (MI.getOperand(1).getIntrinsicID()) {
+    case Intrinsic::amdgcn_sbfe:
+      return true;
+    case Intrinsic::amdgcn_ubfe:
+      return false;
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arsenm wrote:

Don't really need to handle the false cases. Just the two positives 

https://github.com/llvm/llvm-project/pull/132381