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

[Antonio Frighetto via llvm-commits]

antoniofrighetto wrote:

@dvyukov, hard to assess the impact of the change qualitatively. Looking for calls in tail position w/ ret value used over glibc (`grep -r -P 'return.*\b(strcpy|strncpy|memset|memcpy|memmove).*\(.*\).*;' .`) reveals 52 instances of tail call opportunities, which possibly doesn't seem a huge number (out of total # functions?), but they all seem within highly recurring functions (e.g., malloc, strdup – as already noted in the issue).

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