[PATCH] D28881: LiveIntervalAnalysis: Calculate liveness even if a superreg is reserved.

[Matthias Braun via Phabricator via llvm-commits]

MatzeB added a comment.

So we don't really have a concept of reserving register units, we just reserve registers; This patch currenly considers a register unit as reserved if all the root registers are reserved. This turned out to be a bad idea for the X86 32bit mode which reserves BIL, SIL, ... but of course still wants to use the 16+32bit versions of those register.

So I tried changing this to a register unit is considered reserved if the roots and all their super registers are reserved. This fixes all X86 cases but now breaks a number of tests on PowerPC and Hexagon (fun times).


Repository:
  rL LLVM

https://reviews.llvm.org/D28881