[llvm] [InstCombine] Simplify phi using KnownBits of condition (PR #134712)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

> Compile-time overhead: +~0.2%

11728 files changed, 23367619 insertions(+), 24618099 deletions(-)
TBH this patch leads to many attractive optimizations on real-world programs :) I think the compile-time overhead is acceptable. Can we further reduce the overhead by limiting the recursive depth?

However, specially-handling the PHI node in `computeKnownBitsFromContext` is still an ugly way. Can you try `CondContext`?


https://github.com/llvm/llvm-project/pull/134712