[Mlir-commits] [mlir] 730acdc - [MLIR][Presburger] fix double increment in coalesce

[Arjun P]

Author: Michel Weber
Date: 2022-02-26T10:37:19Z
New Revision: 730acdc4454ca581211f447f07579cdaf79e2558

URL: https://github.com/llvm/llvm-project/commit/730acdc4454ca581211f447f07579cdaf79e2558
DIFF: https://github.com/llvm/llvm-project/commit/730acdc4454ca581211f447f07579cdaf79e2558.diff

LOG: [MLIR][Presburger] fix double increment in coalesce

In the main-loop of the current coalesce implementation `i` was incremented
twice for some cases. This patch fixes this bug and adds a regression
testcase.

Reviewed By: arjunp

Differential Revision: https://reviews.llvm.org/D120613

Added: 
    

Modified: 
    mlir/lib/Analysis/Presburger/PresburgerSet.cpp
    mlir/unittests/Analysis/Presburger/PresburgerSetTest.cpp

Removed: 
    


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diff  --git a/mlir/lib/Analysis/Presburger/PresburgerSet.cpp b/mlir/lib/Analysis/Presburger/PresburgerSet.cpp
index b67dc4af4760d..662f2b54dd985 100644
--- a/mlir/lib/Analysis/Presburger/PresburgerSet.cpp
+++ b/mlir/lib/Analysis/Presburger/PresburgerSet.cpp
@@ -521,7 +521,7 @@ PresburgerSet PresburgerSet::coalesce() const {
   // When coalescing is successful, the contained IntegerPolyhedron is swapped
   // with the last element of `polyhedrons` and subsequently erased and
   // similarly for simplices.
-  for (unsigned i = 0; i < polyhedrons.size(); ++i) {
+  for (unsigned i = 0; i < polyhedrons.size();) {
 
     // TODO: This does some comparisons two times (index 0 with 1 and index 1
     // with 0).

diff  --git a/mlir/unittests/Analysis/Presburger/PresburgerSetTest.cpp b/mlir/unittests/Analysis/Presburger/PresburgerSetTest.cpp
index 698db2c17a1a2..05a1c0a1129be 100644
--- a/mlir/unittests/Analysis/Presburger/PresburgerSetTest.cpp
+++ b/mlir/unittests/Analysis/Presburger/PresburgerSetTest.cpp
@@ -619,6 +619,17 @@ TEST(SetTest, coalesceThreeContained) {
   expectCoalesce(1, set);
 }
 
+TEST(SetTest, coalesceDoubleIncrement) {
+  PresburgerSet set = parsePresburgerSetFromPolyStrings(
+      1, {
+             "(x) : (x == 0)",
+             "(x) : (x - 2 == 0)",
+             "(x) : (x + 2 == 0)",
+             "(x) : (x - 2 >= 0, -x + 3 >= 0)",
+         });
+  expectCoalesce(3, set);
+}
+
 static void
 expectComputedVolumeIsValidOverapprox(const PresburgerSet &set,
                                       Optional<uint64_t> trueVolume,