From d2750191465b1a6b59011ad49a8a5a34577557e6 Mon Sep 17 00:00:00 2001
From: Michael Sharp <misharp@microsoft.com>
Date: Tue, 11 Jun 2024 16:18:17 -0600
Subject: [PATCH] changes to use const for stack alloc comparison

---
 .../Numerics/Tensors/netcore/ReadOnlyTensorSpan.cs   | 10 +++++-----
 .../System/Numerics/Tensors/netcore/TensorSpan.cs    | 12 ++++++------
 .../Numerics/Tensors/netcore/TensorSpanExtensions.cs |  2 ++
 3 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ReadOnlyTensorSpan.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ReadOnlyTensorSpan.cs
index 7907da7a17060c..9b0c30b58c2439 100644
--- a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ReadOnlyTensorSpan.cs
+++ b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/ReadOnlyTensorSpan.cs
@@ -522,7 +522,7 @@ public void CopyTo(scoped TensorSpan<T> destination)
             {
                 scoped Span<nint> curIndexes;
                 nint[]? curIndexesArray;
-                if (Rank > 5)
+                if (Rank > TensorSpan.MaxRankForStackAlloc)
                 {
                     curIndexesArray = ArrayPool<nint>.Shared.Rent(Rank);
                     curIndexes = curIndexesArray;
@@ -569,7 +569,7 @@ public bool TryCopyTo(scoped TensorSpan<T> destination)
             {
                 scoped Span<nint> curIndexes;
                 nint[]? curIndexesArray;
-                if (Rank > 5)
+                if (Rank > TensorSpan.MaxRankForStackAlloc)
                 {
                     curIndexesArray = ArrayPool<nint>.Shared.Rent(Rank);
                     curIndexes = curIndexesArray;
@@ -653,7 +653,7 @@ public ReadOnlyTensorSpan<T> Slice(params scoped ReadOnlySpan<NRange> ranges)
 
             scoped Span<nint> lengths;
             scoped Span<nint> offsets;
-            if (Rank > 5)
+            if (Rank > TensorSpan.MaxRankForStackAlloc)
             {
                 lengths = stackalloc nint[Rank];
                 offsets = stackalloc nint[Rank];
@@ -692,7 +692,7 @@ public bool TryFlattenTo(scoped Span<T> destination)
             {
                 scoped Span<nint> curIndexes;
                 nint[]? curIndexesArray;
-                if (Rank > 5)
+                if (Rank > TensorSpan.MaxRankForStackAlloc)
                 {
                     curIndexesArray = ArrayPool<nint>.Shared.Rent(Rank);
                     curIndexes = curIndexesArray;
@@ -733,7 +733,7 @@ public void FlattenTo(scoped Span<T> destination)
 
             scoped Span<nint> curIndexes;
             nint[]? curIndexesArray;
-            if (Rank > 5)
+            if (Rank > TensorSpan.MaxRankForStackAlloc)
             {
                 curIndexesArray = ArrayPool<nint>.Shared.Rent(Rank);
                 curIndexes = curIndexesArray;
diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpan.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpan.cs
index b85c11d29b427b..c64deebe4b3335 100644
--- a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpan.cs
+++ b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpan.cs
@@ -505,7 +505,7 @@ public void Clear()
         {
             scoped Span<nint> curIndexes;
             nint[]? curIndexesArray;
-            if (Rank > 5)
+            if (Rank > TensorSpan.MaxRankForStackAlloc)
             {
                 curIndexesArray = ArrayPool<nint>.Shared.Rent(Rank);
                 curIndexes = curIndexesArray;
@@ -570,7 +570,7 @@ public void CopyTo(scoped TensorSpan<T> destination)
 
             scoped Span<nint> curIndexes;
             nint[]? curIndexesArray;
-            if (Rank > 5)
+            if (Rank > TensorSpan.MaxRankForStackAlloc)
             {
                 curIndexesArray = ArrayPool<nint>.Shared.Rent(Rank);
                 curIndexes = curIndexesArray;
@@ -613,7 +613,7 @@ public bool TryCopyTo(scoped TensorSpan<T> destination)
             {
                 scoped Span<nint> curIndexes;
                 nint[]? curIndexesArray;
-                if (Rank > 5)
+                if (Rank > TensorSpan.MaxRankForStackAlloc)
                 {
                     curIndexesArray = ArrayPool<nint>.Shared.Rent(Rank);
                     curIndexes = curIndexesArray;
@@ -703,7 +703,7 @@ public TensorSpan<T> Slice(params scoped ReadOnlySpan<NRange> ranges)
 
             scoped Span<nint> lengths;
             scoped Span<nint> offsets;
-            if (Rank > 5)
+            if (Rank > TensorSpan.MaxRankForStackAlloc)
             {
                 lengths = stackalloc nint[Rank];
                 offsets = stackalloc nint[Rank];
@@ -745,7 +745,7 @@ public bool TryFlattenTo(scoped Span<T> destination)
             {
                 scoped Span<nint> curIndexes;
                 nint[]? curIndexesArray;
-                if (Rank > 5)
+                if (Rank > TensorSpan.MaxRankForStackAlloc)
                 {
                     curIndexesArray = ArrayPool<nint>.Shared.Rent(Rank);
                     curIndexes = curIndexesArray;
@@ -786,7 +786,7 @@ public void FlattenTo(scoped Span<T> destination)
 
             scoped Span<nint> curIndexes;
             nint[]? curIndexesArray;
-            if (Rank > 5)
+            if (Rank > TensorSpan.MaxRankForStackAlloc)
             {
                 curIndexesArray = ArrayPool<nint>.Shared.Rent(Rank);
                 curIndexes = curIndexesArray;
diff --git a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpanExtensions.cs b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpanExtensions.cs
index 88c280d27ae4ed..ce9d88447d1fc5 100644
--- a/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpanExtensions.cs
+++ b/src/libraries/System.Numerics.Tensors/src/System/Numerics/Tensors/netcore/TensorSpanExtensions.cs
@@ -12,6 +12,8 @@ namespace System.Numerics.Tensors
 {
     public static class TensorSpan
     {
+        internal const int MaxRankForStackAlloc = 5;
+
         #region SequenceEqual
         /// <summary>
         /// Determines whether two sequences are equal by comparing the elements using IEquatable{T}.Equals(T).