Teach the code generator that shrd/shld is commutable if it has an immediate.
This allows us to generate this:
foo:
mov %EAX, DWORD PTR [%ESP + 4]
mov %EDX, DWORD PTR [%ESP + 8]
shld %EDX, %EDX, 2
shl %EAX, 2
ret
instead of this:
foo:
mov %EAX, DWORD PTR [%ESP + 4]
mov %ECX, DWORD PTR [%ESP + 8]
mov %EDX, %EAX
shrd %EDX, %ECX, 30
shl %EAX, 2
ret
Note the magically transmogrifying immediate.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19686 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed