[Mlir-commits] [mlir] 79f35a2 - [MLIR][Presburger] Make getSubMatrix exclusive on the right end (#190911)

[llvmlistbot at llvm.org]

Author: Yue Huang
Date: 2026-05-06T10:14:22+01:00
New Revision: 79f35a2185e99a0de5280962bc69cde174c31fc9

URL: https://github.com/llvm/llvm-project/commit/79f35a2185e99a0de5280962bc69cde174c31fc9
DIFF: https://github.com/llvm/llvm-project/commit/79f35a2185e99a0de5280962bc69cde174c31fc9.diff

LOG: [MLIR][Presburger] Make getSubMatrix exclusive on the right end (#190911)

Currently `getSubMatrix(fromRow, toRow, fromCol, toCol)` forms a
submatrix with both ends inclusive. In this way, it's impossible to form
an empty submatrix, as the assertions in the function prevents cases
where `toRow < fromRow`. However, the functionality is necessary for
Barvinok procedures (e.g. we might want to inspect the submatrix for
parameters, which will be empty if there's none).

This PR changes it to be inclusive on the left end and exclusive on the
right end, making it the same as canonical C++ ranges.

Added: 
    

Modified: 
    mlir/include/mlir/Analysis/Presburger/Matrix.h
    mlir/lib/Analysis/Presburger/Barvinok.cpp
    mlir/lib/Analysis/Presburger/Matrix.cpp

Removed: 
    


################################################################################
diff  --git a/mlir/include/mlir/Analysis/Presburger/Matrix.h b/mlir/include/mlir/Analysis/Presburger/Matrix.h
index 1f10ea2078ad3..96afef1bd3105 100644
--- a/mlir/include/mlir/Analysis/Presburger/Matrix.h
+++ b/mlir/include/mlir/Analysis/Presburger/Matrix.h
@@ -196,7 +196,8 @@ class Matrix {
 
   // Copy the cells in the intersection of
   // the rows between `fromRows` and `toRows` and
-  // the columns between `fromColumns` and `toColumns`, both inclusive.
+  // the columns between `fromColumns` and `toColumns`, inclusive on the left
+  // but exclusive on the right (same as canonical C++ ranges).
   Matrix<T> getSubMatrix(unsigned fromRow, unsigned toRow, unsigned fromColumn,
                          unsigned toColumn) const;
 

diff  --git a/mlir/lib/Analysis/Presburger/Barvinok.cpp b/mlir/lib/Analysis/Presburger/Barvinok.cpp
index c31b27794f01e..e27658a37ad12 100644
--- a/mlir/lib/Analysis/Presburger/Barvinok.cpp
+++ b/mlir/lib/Analysis/Presburger/Barvinok.cpp
@@ -167,9 +167,9 @@ mlir::presburger::detail::solveParametricEquations(FracMatrix equations) {
 
   // If the determinant is zero, there is no unique solution.
   // Thus we return null.
-  if (FracMatrix(equations.getSubMatrix(/*fromRow=*/0, /*toRow=*/d - 1,
+  if (FracMatrix(equations.getSubMatrix(/*fromRow=*/0, /*toRow=*/d,
                                         /*fromColumn=*/0,
-                                        /*toColumn=*/d - 1))
+                                        /*toColumn=*/d))
           .determinant() == 0)
     return std::nullopt;
 
@@ -218,8 +218,8 @@ mlir::presburger::detail::solveParametricEquations(FracMatrix equations) {
   //
   // We copy these columns and return them.
   ParamPoint vertex =
-      equations.getSubMatrix(/*fromRow=*/0, /*toRow=*/d - 1,
-                             /*fromColumn=*/d, /*toColumn=*/numCols - 1);
+      equations.getSubMatrix(/*fromRow=*/0, /*toRow=*/d,
+                             /*fromColumn=*/d, /*toColumn=*/numCols);
   vertex.negateMatrix();
   return vertex;
 }
@@ -345,10 +345,9 @@ mlir::presburger::detail::computePolytopeGeneratingFunction(
     // b2c2 stores the coefficients of the parameters and the constant term.
     FracMatrix a2(numIneqs - numVars, numVars);
     FracMatrix b2c2(numIneqs - numVars, numSymbols + 1);
-    a2 = FracMatrix(
-        remainder.getSubMatrix(0, numIneqs - numVars - 1, 0, numVars - 1));
-    b2c2 = FracMatrix(remainder.getSubMatrix(0, numIneqs - numVars - 1, numVars,
-                                             numVars + numSymbols));
+    a2 = FracMatrix(remainder.getSubMatrix(0, numIneqs - numVars, 0, numVars));
+    b2c2 = FracMatrix(remainder.getSubMatrix(0, numIneqs - numVars, numVars,
+                                             numVars + numSymbols + 1));
 
     // Find the vertex, if any, corresponding to the current subset of
     // inequalities.

diff  --git a/mlir/lib/Analysis/Presburger/Matrix.cpp b/mlir/lib/Analysis/Presburger/Matrix.cpp
index 02a3b61b6cf42..89d8a15422d95 100644
--- a/mlir/lib/Analysis/Presburger/Matrix.cpp
+++ b/mlir/lib/Analysis/Presburger/Matrix.cpp
@@ -392,13 +392,13 @@ Matrix<T> Matrix<T>::getSubMatrix(unsigned fromRow, unsigned toRow,
                                   unsigned fromColumn,
                                   unsigned toColumn) const {
   assert(fromRow <= toRow && "end of row range must be after beginning!");
-  assert(toRow < nRows && "end of row range out of bounds!");
+  assert(toRow <= nRows && "end of row range out of bounds!");
   assert(fromColumn <= toColumn &&
          "end of column range must be after beginning!");
-  assert(toColumn < nColumns && "end of column range out of bounds!");
-  Matrix<T> subMatrix(toRow - fromRow + 1, toColumn - fromColumn + 1);
-  for (unsigned i = fromRow; i <= toRow; ++i)
-    for (unsigned j = fromColumn; j <= toColumn; ++j)
+  assert(toColumn <= nColumns && "end of column range out of bounds!");
+  Matrix<T> subMatrix(toRow - fromRow, toColumn - fromColumn);
+  for (unsigned i = fromRow; i < toRow; ++i)
+    for (unsigned j = fromColumn; j < toColumn; ++j)
       subMatrix(i - fromRow, j - fromColumn) = at(i, j);
   return subMatrix;
 }