[DAG] Don't perform SINT_TO_FP<->UINT_TO_FP custom conversion after legalization

The SINT_TO_FP<->UINT_TO_FP combines for non-negative integers should only occur for legal ops once LegalOperations = true

No test case to hand, noticed when investigating PR38226 + PR38970

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@343405 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed