[ARM] Fix computeKnownBits for ARMISD::CMOV
Summary:
The true and false operands for the CMOV are operands 0 and 1.
ARMISelLowering.cpp::computeKnownBits was looking at operands 1 and 2
instead. This can cause CMOV instructions to be incorrectly folded into
BFI if value set by the CMOV is another CMOV, whose known bits are
computed incorrectly.
This patch fixes the issue and adds a test case.
Reviewers: kristof.beyls, jmolloy
Subscribers: llvm-commits, aemerson, srhines, rengolin
Differential Revision: https://reviews.llvm.org/D31265
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@298624 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed
