[llvm] [CGP] Consider arguments and ret values in `dupRetToEnableTailCallOpts` (PR #76613)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> @dtcxzyw, thanks, restrained the folding to ret values of function calls and function arguments, and considering essentially only libc functions (whose first argument coincides with the return value).

The regression has been fixed. Thank you!


https://github.com/llvm/llvm-project/pull/76613