[llvm] [DebugInfo][InstCombine] When replacing bswap idiom, add DebugLoc to new insts (PR #114231)

[David Blaikie via llvm-commits]

dwblaikie wrote:

Should/does this use a merged location? (the test and patch description mention several instructions being replaced by several other instructions - so sounds like the new instructions should get the merged location of all the old instructions? But not clear if that's what's happening, or just the last of the old instructions is used as the location for the new ones?)

https://github.com/llvm/llvm-project/pull/114231