cb8d83a77c
The assertion in #80597 failed when we were trying to compute known bits
of a value in an unreachable BB.
859b09da08/llvm/lib/Transforms/InstCombine/InstCombineSimplifyDemanded.cpp (L749-L810)
In this case, `SignBits` is 30 (deduced from instr info), but `Known` is
`10000101010111010011110101000?0?00000000000000000000000000000000`
(deduced from dom cond). Setting high bits of `lshr Known, 1` will lead
to conflict.
This patch masks out high bits of `Known.Zero` to address this problem.
Fixes #80597.
76 KiB
76 KiB