commit 0e7a8a9027c5f5862c3c78f41c777ba2930f9b23
author Nicolas Vasilache <ntv@google.com> Sat Jan 26 18:41:17 2019
committer jpienaar <jpienaar@google.com> Fri Mar 29 22:40:08 2019
tree 943c4fbf692361d86ff3a7dd1d91962a30f92d9f
parent 81c7f2e2f3bf34bc45915bbb3eb44f37331aff91

Drop AffineMap::Null and IntegerSet::Null

Addresses b/122486036

This CL addresses some leftover crumbs in AffineMap and IntegerSet by removing
the Null method and cleaning up the constructors.

As the ::Null uses were tracked down, opportunities appeared to untangle some
of the Parsing logic and make it explicit where AffineMap/IntegerSet have
ambiguous syntax. Previously, ambiguous cases were hidden behind the implicit
pointer values of AffineMap* and IntegerSet* that were passed as function
parameters. Depending the values of those pointers one of 3 behaviors could
occur.

This parsing logic convolution is one of the rare cases where I would advocate
for code duplication. The more proper fix would be to make the syntax
unambiguous or to allow some lookahead.

PiperOrigin-RevId: 231058512

mlir/lib/Transforms/LoopFusion.cpp

diff --git a/mlir/lib/Transforms/LoopFusion.cpp b/mlir/lib/Transforms/LoopFusion.cpp
index 77a4559..cee0a08 100644
--- a/mlir/lib/Transforms/LoopFusion.cpp
+++ b/mlir/lib/Transforms/LoopFusion.cpp
@@ -595,7 +595,7 @@
   for (unsigned i = 0; i < numSrcLoopIVs; ++i) {
     AffineMap lbMap = sliceState->lbs[i];
     AffineMap ubMap = sliceState->ubs[i];
-    if (lbMap == AffineMap::Null() || ubMap == AffineMap::Null()) {
+    if (lbMap == AffineMap() || ubMap == AffineMap()) {
       // The iteration of src loop IV 'i' was not sliced. Use full loop bounds.
       if (srcLoopIVs[i]->hasConstantLowerBound() &&
           srcLoopIVs[i]->hasConstantUpperBound()) {
@@ -675,16 +675,16 @@
   for (unsigned i = 0, e = sliceStateA.lbs.size(); i < e; ++i) {
     AffineMap lbMapA = sliceStateA.lbs[i];
     AffineMap ubMapA = sliceStateA.ubs[i];
-    if (lbMapA == AffineMap::Null()) {
-      assert(ubMapA == AffineMap::Null());
+    if (lbMapA == AffineMap()) {
+      assert(ubMapA == AffineMap());
       continue;
     }
     assert(ubMapA && "expected non-null ub map");
 
     AffineMap lbMapB = sliceStateB->lbs[i];
     AffineMap ubMapB = sliceStateB->ubs[i];
-    if (lbMapB == AffineMap::Null()) {
-      assert(ubMapB == AffineMap::Null());
+    if (lbMapB == AffineMap()) {
+      assert(ubMapB == AffineMap());
       // Union 'sliceStateB' does not have a bound for 'i' so copy from A.
       sliceStateB->lbs[i] = lbMapA;
       sliceStateB->ubs[i] = ubMapA;
@@ -799,7 +799,7 @@
   }
   auto indexRemap =
       zeroOffsetCount == rank
-          ? AffineMap::Null()
+          ? AffineMap()
           : b.getAffineMap(outerIVs.size() + rank, 0, remapExprs, {});
   // Replace all users of 'oldMemRef' with 'newMemRef'.
   bool ret =
@@ -1107,11 +1107,11 @@
 
   // Canonicalize slice bound affine maps.
   for (unsigned i = 0; i < numSrcLoopIVs; ++i) {
-    if (sliceState->lbs[i] != AffineMap::Null()) {
+    if (sliceState->lbs[i] != AffineMap()) {
       canonicalizeMapAndOperands(&sliceState->lbs[i],
                                  &sliceState->lbOperands[i]);
     }
-    if (sliceState->ubs[i] != AffineMap::Null()) {
+    if (sliceState->ubs[i] != AffineMap()) {
       canonicalizeMapAndOperands(&sliceState->ubs[i],
                                  &sliceState->ubOperands[i]);
     }