converted to LEA64_32r in x86's convertToThreeAddress. This
replaces code like this:
movl %esi, %edi
inc %edi
with this:
lea 1(%rsi), %edi
which appears to be beneficial.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61830 91177308-0d34-0410-b5e6-96231b3b80d8