[TargetLowering] Rename DAGCombinerInfo::isAfterLegalizeVectorOps to DAGCombiner::isAfterLegalizeDAG since that's what it checks. NFC

The code checks Level == AfterLegalizeDAG which is the fourth and last of the possible DAG combine stages that we have.

There is a Level called AfterLegalVectorOps, but that's the third DAG combine and it doesn't always run.

A function called isAfterLegalVectorOps should imply it returns true in either of the DAG combines that runs after the legalize vector ops stage, but that's not what this function does.

llvm-svn: 326832
diff --git a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
index 94d1e3a..54aef36 100644
--- a/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/SIISelLowering.cpp
@@ -5904,7 +5904,7 @@
   // easier if i8 vectors weren't promoted to i32 vectors, particularly after
   // types are legalized. v4i8 -> v4f32 is probably the only case to worry
   // about in practice.
-  if (DCI.isAfterLegalizeVectorOps() && SrcVT == MVT::i32) {
+  if (DCI.isAfterLegalizeDAG() && SrcVT == MVT::i32) {
     if (DAG.MaskedValueIsZero(Src, APInt::getHighBitsSet(32, 24))) {
       SDValue Cvt = DAG.getNode(AMDGPUISD::CVT_F32_UBYTE0, DL, VT, Src);
       DCI.AddToWorklist(Cvt.getNode());