[llvm] [X86] Consistently use f128 libcalls (PR #142386)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon approved this pull request.

LGTM - although this probably should be mentioned in the release notes

Do we have any test-suite benchmarks that use f128?

https://github.com/llvm/llvm-project/pull/142386