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

[Pierre van Houtryve via llvm-commits]

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@@ -225,6 +228,103 @@ void RegBankLegalizeHelper::lower(MachineInstr &MI,
     MI.eraseFromParent();
     break;
   }
+  case Div_BFE: {
+    Register Dst = MI.getOperand(0).getReg();
+    assert(MRI.getType(Dst) == LLT::scalar(64));
+    bool Signed = isa<GIntrinsic>(MI) ? MI.getOperand(1).getIntrinsicID() ==
+                                            Intrinsic::amdgcn_sbfe
+                                      : MI.getOpcode() == AMDGPU::G_SBFX;
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Pierre-vh wrote:

Move this into a `isSignedBFE` helper and reuse it below too ?
A 3 line ternary is a bit hard to read IMO

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