llvm-project

2108c623 - [X86] narrowBitOpRMW - add handling for single bit insertion patterns (#165742)

[X86] narrowBitOpRMW - add handling for single bit insertion patterns (#165742) Insertion of a single bit into a large integer is typically canonicalized to "(X & ~(1 << ShAmt)) | (InsertBit << ShAmt)", which can be simplified to modify the i32 block as a BTR followed by an OR((i32)InsertBit << (ShAmt % 32). We must ensure that the InsertBit is zero apart from the LSB so we can cheaply truncate it to work with the i32 block like the simpler BT patterns.