[clang] [llvm] [HLSL] Implement elementwise firstbitlow builtin (PR #116858)

[Sarah Spall via llvm-commits]

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@@ -96,15 +96,20 @@ class SPIRVInstructionSelector : public InstructionSelector {
   bool selectFirstBitHigh(Register ResVReg, const SPIRVType *ResType,
                           MachineInstr &I, bool IsSigned) const;
 
-  bool selectFirstBitHigh16(Register ResVReg, const SPIRVType *ResType,
-                            MachineInstr &I, bool IsSigned) const;
+  bool selectFirstBitLow(Register ResVReg, const SPIRVType *ResType,
+                         MachineInstr &I) const;
+
+  bool selectFirstBitSet16(Register ResVReg, const SPIRVType *ResType,
+                           MachineInstr &I, unsigned ExtendOpcode,
+                           unsigned BitSetOpcode) const;
 
-  bool selectFirstBitHigh32(Register ResVReg, const SPIRVType *ResType,
-                            MachineInstr &I, Register SrcReg,
-                            bool IsSigned) const;
+  bool selectFirstBitSet32(Register ResVReg, const SPIRVType *ResType,
+                           MachineInstr &I, Register SrcReg,
+                           unsigned Opcode) const;
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spall wrote:

Nit: rename this to be BitSetOpcode to match the other functions?

https://github.com/llvm/llvm-project/pull/116858