[llvm] [X86] Return more accurate getNumSupportedRegs() (NFC) (PR #71690)

[Shengchen Kan via llvm-commits]

KanRobert wrote:

> LGTM, thanks @nikic! Ashamed not found this problem during review :(

Not your fault. 
https://github.com/llvm/llvm-project/pull/70222/commits/9d3bec6a2bd3d88af5d09331b29c6adc8f996dcc

I did this on purpose to make the regression introduced by EGPR support look smaller. But unfortunately, the regression was still observed.


https://github.com/llvm/llvm-project/pull/71690