[Mlir-commits] [mlir] [mlir][presburger] Implement moveColumns using std::rotate (PR #168243)
lonely eagle
llvmlistbot at llvm.org
Mon Dec 1 17:53:03 PST 2025
https://github.com/linuxlonelyeagle updated https://github.com/llvm/llvm-project/pull/168243
>From 3401dd23da410728627b8ce93b5ee5aea6ea42c8 Mon Sep 17 00:00:00 2001
From: linuxlonelyeagle <2020382038 at qq.com>
Date: Sat, 15 Nov 2025 21:26:35 +0000
Subject: [PATCH 1/4] Implement moveColumns using std::rotate.
---
mlir/lib/Analysis/Presburger/Matrix.cpp | 44 +++++++++++--------------
1 file changed, 20 insertions(+), 24 deletions(-)
diff --git a/mlir/lib/Analysis/Presburger/Matrix.cpp b/mlir/lib/Analysis/Presburger/Matrix.cpp
index bb6056487512a..7933bec8d6da1 100644
--- a/mlir/lib/Analysis/Presburger/Matrix.cpp
+++ b/mlir/lib/Analysis/Presburger/Matrix.cpp
@@ -255,13 +255,7 @@ void Matrix<T>::fillRow(unsigned row, const T &value) {
}
// moveColumns is implemented by moving the columns adjacent to the source range
-// to their final position. When moving right (i.e. dstPos > srcPos), the range
-// of the adjacent columns is [srcPos + num, dstPos + num). When moving left
-// (i.e. dstPos < srcPos) the range of the adjacent columns is [dstPos, srcPos).
-// First, zeroed out columns are inserted in the final positions of the adjacent
-// columns. Then, the adjacent columns are moved to their final positions by
-// swapping them with the zeroed columns. Finally, the now zeroed adjacent
-// columns are deleted.
+// to their final position.
template <typename T>
void Matrix<T>::moveColumns(unsigned srcPos, unsigned num, unsigned dstPos) {
if (num == 0)
@@ -276,23 +270,25 @@ void Matrix<T>::moveColumns(unsigned srcPos, unsigned num, unsigned dstPos) {
assert(dstPos + num <= getNumColumns() &&
"move destination range exceeds matrix columns");
- unsigned insertCount = offset > 0 ? offset : -offset;
- unsigned finalAdjStart = offset > 0 ? srcPos : srcPos + num;
- unsigned curAdjStart = offset > 0 ? srcPos + num : dstPos;
- // TODO: This can be done using std::rotate.
- // Insert new zero columns in the positions where the adjacent columns are to
- // be moved.
- insertColumns(finalAdjStart, insertCount);
- // Update curAdjStart if insertion of new columns invalidates it.
- if (finalAdjStart < curAdjStart)
- curAdjStart += insertCount;
-
- // Swap the adjacent columns with inserted zero columns.
- for (unsigned i = 0; i < insertCount; ++i)
- swapColumns(finalAdjStart + i, curAdjStart + i);
-
- // Delete the now redundant zero columns.
- removeColumns(curAdjStart, insertCount);
+ unsigned numRows = getNumRows();
+ unsigned numCols = getNumReservedColumns();
+
+ if (offset > 0) {
+ // shift the matrix left, see
+ // https://en.cppreference.com/w/cpp/algorithm/rotate.html.
+ for (unsigned i = 0; i < numRows; ++i) {
+ auto begin = data.begin() + i * numCols + srcPos;
+ auto end = data.begin() + i * numCols + dstPos + num;
+ std::rotate(begin, begin + num, end);
+ }
+ } else {
+ // shift the matrix right.
+ for (unsigned i = 0; i < numRows; ++i) {
+ auto begin = data.begin() + i * numCols + srcPos + num;
+ auto end = data.begin() + i * numCols + dstPos;
+ std::rotate(end, begin - num, begin);
+ }
+ }
}
template <typename T>
>From aeb6c1c48c1f4bbddd809514043db0f1dea3f491 Mon Sep 17 00:00:00 2001
From: linuxlonelyeagle <2020382038 at qq.com>
Date: Sat, 22 Nov 2025 11:18:23 +0000
Subject: [PATCH 2/4] update code and rebase main.
---
mlir/lib/Analysis/Presburger/Matrix.cpp | 24 +++++++++++-------------
1 file changed, 11 insertions(+), 13 deletions(-)
diff --git a/mlir/lib/Analysis/Presburger/Matrix.cpp b/mlir/lib/Analysis/Presburger/Matrix.cpp
index 7933bec8d6da1..01c607c09f2b3 100644
--- a/mlir/lib/Analysis/Presburger/Matrix.cpp
+++ b/mlir/lib/Analysis/Presburger/Matrix.cpp
@@ -271,23 +271,21 @@ void Matrix<T>::moveColumns(unsigned srcPos, unsigned num, unsigned dstPos) {
"move destination range exceeds matrix columns");
unsigned numRows = getNumRows();
- unsigned numCols = getNumReservedColumns();
if (offset > 0) {
- // shift the matrix left, see
- // https://en.cppreference.com/w/cpp/algorithm/rotate.html.
+ // Shift the matrix left, because start < end, that std::rotate(start,
+ // middle, end) turns the range [start, end] to [middle, end) + [start,
+ // middle).
for (unsigned i = 0; i < numRows; ++i) {
- auto begin = data.begin() + i * numCols + srcPos;
- auto end = data.begin() + i * numCols + dstPos + num;
- std::rotate(begin, begin + num, end);
- }
- } else {
- // shift the matrix right.
- for (unsigned i = 0; i < numRows; ++i) {
- auto begin = data.begin() + i * numCols + srcPos + num;
- auto end = data.begin() + i * numCols + dstPos;
- std::rotate(end, begin - num, begin);
+ std::rotate(&at(i, srcPos), &at(i, srcPos) + num, &at(i, dstPos) + num);
}
+ return;
+ }
+ // Shift the matrix right. because end < start, that std::rotate(start,
+ // middle, end) turns the range [start, end] to [middle, start) + [end,
+ // middle).
+ for (unsigned i = 0; i < numRows; ++i) {
+ std::rotate(&at(i, dstPos), &at(i, srcPos), &at(i, srcPos) + num);
}
}
>From eeb2ca4698b18cf577d8b59b6c4b19d077cb483e Mon Sep 17 00:00:00 2001
From: linuxlonelyeagle <2020382038 at qq.com>
Date: Mon, 1 Dec 2025 17:40:54 +0000
Subject: [PATCH 3/4] update code.
---
mlir/lib/Analysis/Presburger/Matrix.cpp | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)
diff --git a/mlir/lib/Analysis/Presburger/Matrix.cpp b/mlir/lib/Analysis/Presburger/Matrix.cpp
index 01c607c09f2b3..7be1475d83ae3 100644
--- a/mlir/lib/Analysis/Presburger/Matrix.cpp
+++ b/mlir/lib/Analysis/Presburger/Matrix.cpp
@@ -261,8 +261,7 @@ void Matrix<T>::moveColumns(unsigned srcPos, unsigned num, unsigned dstPos) {
if (num == 0)
return;
- int offset = dstPos - srcPos;
- if (offset == 0)
+ if (dstPos == srcPos)
return;
assert(srcPos + num <= getNumColumns() &&
@@ -272,18 +271,16 @@ void Matrix<T>::moveColumns(unsigned srcPos, unsigned num, unsigned dstPos) {
unsigned numRows = getNumRows();
- if (offset > 0) {
- // Shift the matrix left, because start < end, that std::rotate(start,
- // middle, end) turns the range [start, end] to [middle, end) + [start,
- // middle).
+ if (dstPos > srcPos) {
+ // std::rotate(start, middle, end) permutes the elements of [start, end] to
+ // [middle, end) + [start, middle).
for (unsigned i = 0; i < numRows; ++i) {
std::rotate(&at(i, srcPos), &at(i, srcPos) + num, &at(i, dstPos) + num);
}
return;
}
- // Shift the matrix right. because end < start, that std::rotate(start,
- // middle, end) turns the range [start, end] to [middle, start) + [end,
- // middle).
+ // std::rotate(start, middle, end) permutes the elements of [start, end] to
+ // [middle, start) + [end, middle).
for (unsigned i = 0; i < numRows; ++i) {
std::rotate(&at(i, dstPos), &at(i, srcPos), &at(i, srcPos) + num);
}
>From cb4fc5e21efec7394d9eac160b970dc372a2f8da Mon Sep 17 00:00:00 2001
From: linuxlonelyeagle <2020382038 at qq.com>
Date: Tue, 2 Dec 2025 01:52:47 +0000
Subject: [PATCH 4/4] change comment.
---
mlir/lib/Analysis/Presburger/Matrix.cpp | 8 +++-----
1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/mlir/lib/Analysis/Presburger/Matrix.cpp b/mlir/lib/Analysis/Presburger/Matrix.cpp
index 7be1475d83ae3..83a2c280c3d4e 100644
--- a/mlir/lib/Analysis/Presburger/Matrix.cpp
+++ b/mlir/lib/Analysis/Presburger/Matrix.cpp
@@ -270,17 +270,15 @@ void Matrix<T>::moveColumns(unsigned srcPos, unsigned num, unsigned dstPos) {
"move destination range exceeds matrix columns");
unsigned numRows = getNumRows();
-
+ // std::rotate(start, middle, end) permutes the elements of [start, end] to
+ // [middle, end) + [start, middle). NOTE: &at(i, srcPos + num) will trigger an
+ // assert.
if (dstPos > srcPos) {
- // std::rotate(start, middle, end) permutes the elements of [start, end] to
- // [middle, end) + [start, middle).
for (unsigned i = 0; i < numRows; ++i) {
std::rotate(&at(i, srcPos), &at(i, srcPos) + num, &at(i, dstPos) + num);
}
return;
}
- // std::rotate(start, middle, end) permutes the elements of [start, end] to
- // [middle, start) + [end, middle).
for (unsigned i = 0; i < numRows; ++i) {
std::rotate(&at(i, dstPos), &at(i, srcPos), &at(i, srcPos) + num);
}
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