[llvm] [GlobalISel] Refactor extractParts() (PR #75223)

[Vladislav Dzhidzhoev via llvm-commits]

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@@ -247,6 +248,24 @@ MachineInstr *getDefIgnoringCopies(Register Reg,
 /// Also walks through hints such as G_ASSERT_ZEXT.
 Register getSrcRegIgnoringCopies(Register Reg, const MachineRegisterInfo &MRI);
 
+/// Helper function to split a wide generic register into bitwise blocks with
+/// the given Type (which implies the number of blocks needed). The generic
+/// registers created are appended to Ops, starting at bit 0 of Reg.
+void extractParts(Register Reg, LLT Ty, int NumParts,
+                  SmallVectorImpl<Register> &VRegs,
+                  MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI);
+
+/// Version which handles irregular splits.
+bool extractParts(Register Reg, LLT RegTy, LLT MainTy, LLT &LeftoverTy,
+                  SmallVectorImpl<Register> &VRegs,
+                  SmallVectorImpl<Register> &LeftoverVRegs,
+                  MachineIRBuilder &MIRBuilder, MachineRegisterInfo &MRI);
+
+/// Version which handles irregular sub-vector splits.
+void extractVectorParts(Register Reg, unsigned NumElst,
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dzhidzhoev wrote:

nit: NumElst -> NumElts

https://github.com/llvm/llvm-project/pull/75223