[DAGCombine] Allow vector constant folding of any value type before type legalization
The patch comes in 2 parts:
1 - it makes use of the SelectionDAG::NewNodesMustHaveLegalTypes flag to tell when it can safely constant fold illegal types.
2 - it correctly resets SelectionDAG::NewNodesMustHaveLegalTypes at the start of each call to SelectionDAGISel::CodeGenAndEmitDAG so all the pre-legalization stages can make use of it - not just the first basic block that gets handled.
Fix for PR30760
Differential Revision: https://reviews.llvm.org/D29568
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@294749 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed