[mlir][Linalg] emitLoopRanges and emitLoopRangesWithSymbols merged into one

Right now there is a branching for 2 functions based on whether target map has
symbols or not. In this commit these functions are merged into one.
Furthermore, emitting does not require inverse and map applying as it computes
the correct Range in a single step and thus reduces unnecessary overhead.

Differential Revision: https://reviews.llvm.org/D83756

Author: limo1996

mlir/lib/Dialect/Linalg/Transforms/Loops.cpp

@@ -58,31 +58,17 @@ static SmallVector<Value, 4> permuteIvs(ArrayRef<Value> ivs,
                      : SmallVector<Value, 4>(ivs.begin(), ivs.end());
 }
 
-// Creates a number of ranges equal to the number of results in `map`.
-// The returned ranges correspond to the loop ranges, in the proper order, for
-// which new loops will be created.
-static SmallVector<SubViewOp::Range, 4>
-emitLoopRanges(OpBuilder &b, Location loc, AffineMap map,
-               ArrayRef<Value> allViewSizes) {
-  // Apply `map` to get view sizes in loop order.
-  auto sizes = applyMapToValues(b, loc, map, allViewSizes);
-  // Create a new range with the applied tile sizes.
-  ScopedContext scope(b, loc);
-  SmallVector<SubViewOp::Range, 4> res;
-  for (unsigned idx = 0, e = map.getNumResults(); idx < e; ++idx) {
-    res.push_back(SubViewOp::Range{std_constant_index(0), sizes[idx],
-                                   std_constant_index(1)});
-  }
-  return res;
-}
-
 /// Creates a number of ranges equal to the number of dimensions in the `map`.
-/// The function supports for now only limited number of expressions inside
-/// map results. It expects a non-inverted, concatenated map and last values in
-/// viewSizes will be applied to the symbols in the map.
-static SmallVector<SubViewOp::Range, 4>
-emitLoopRangesWithSymbols(OpBuilder &b, Location loc, AffineMap map,
-                          ValueRange viewSizes) {
+/// The returned ranges correspond to the loop ranges, in the proper order, for
+/// which new loops will be created.
+/// The function supports only maps that are invertible and have results of type
+/// DimExpr or (DimExpr + DimExpr - SymbolExpr floordiv ConstExpr).
+/// It expects a non-inverted, concatenated map and last values in
+/// allViewSizes will be applied to the symbols in the map if it contains any.
+static SmallVector<SubViewOp::Range, 4> emitLoopRanges(OpBuilder &b,
+                                                       Location loc,
+                                                       AffineMap map,
+                                                       ValueRange viewSizes) {
   unsigned numDims = map.getNumDims(), numRes = map.getNumResults();
   unsigned numSym = map.getNumSymbols();
   assert(viewSizes.size() == numRes + numSym &&
@@ -537,23 +523,8 @@ Optional<LinalgLoops> linalgOpToLoopsImpl(Operation *op, OpBuilder &builder) {
       llvm::map_range(mapsRange, [](AffineMapAttr a) { return a.getValue(); }));
   SmallVector<Value, 8> sizes = getViewSizes(builder, linalgOp);
   AffineMap map = concatAffineMaps(maps);
-  SmallVector<SubViewOp::Range, 4> loopRanges;
-
-  if (map.getNumSymbols()) {
-    loopRanges = emitLoopRangesWithSymbols(scope.getBuilderRef(),
-                                           scope.getLocation(), map, sizes);
-  } else {
-    AffineMap invertedMap = inversePermutation(map);
-    if (!invertedMap)
-      return {};
-    if (invertedMap.isEmpty()) {
-      emitScalarImplementation<IndexedValueTy>({}, linalgOp);
-      return LinalgLoops();
-    }
-
-    loopRanges = emitLoopRanges(scope.getBuilderRef(), scope.getLocation(),
-                                invertedMap, sizes);
-  }
+  auto loopRanges = emitLoopRanges(scope.getBuilderRef(), scope.getLocation(),
+                                   map, getViewSizes(builder, linalgOp));
   SmallVector<Value, 4> allIvs;
   GenerateLoopNest<LoopTy>::doit(
       loopRanges, linalgOp.iterator_types().getValue(), [&](ValueRange ivs) {