Refactor common code getting memref access in getMemRefRegion - NFC

- use getAccessMap() instead of repeating it
- fold getMemRefRegion into MemRefRegion ctor (more natural, avoid heap
  allocation and unique_ptr where possible)

- change extractForInductionVars - MutableArrayRef -> ArrayRef for the
  arguments. Since the method is just returning copies of 'Value *', the client
  can't mutate the pointers themselves; it's fine to mutate the 'Value''s
  themselves, but that doesn't mutate the pointers to those.

- change the way extractForInductionVars returns (see b/123437690)

PiperOrigin-RevId: 232359277

1 files changed, 3 insertions, 2 deletions

diff --git a/mlir/lib/Transforms/MemRefDataFlowOpt.cpp b/mlir/lib/Transforms/MemRefDataFlowOpt.cpp
index b2b69dc7b6d..2d06a327315 100644
--- a/mlir/lib/Transforms/MemRefDataFlowOpt.cpp
+++ b/mlir/lib/Transforms/MemRefDataFlowOpt.cpp
@@ -178,8 +178,9 @@ void MemRefDataFlowOpt::visitInstruction(Instruction *opInst) {
       // is trivially loading from a single location at that depth; so there
       // isn't a need to call isRangeOneToOne.
       if (getNestingDepth(*storeOpInst) < loadOpDepth) {
-        auto region = getMemRefRegion(loadOpInst, nsLoops);
-        if (!region->getConstraints()->isRangeOneToOne(
+        MemRefRegion region(loadOpInst->getLoc());
+        region.compute(loadOpInst, nsLoops);
+        if (!region.getConstraints()->isRangeOneToOne(
                 /*start=*/0, /*limit=*/loadOp->getMemRefType().getRank()))
           break;
       }