From 68b05d4468c664315fb568b85303c68e9ea1d4f4 Mon Sep 17 00:00:00 2001
From: Miha Zupan <mihazupan.zupan1@gmail.com>
Date: Sat, 15 Feb 2020 18:54:51 +0100
Subject: [PATCH] Avoid using stackalloc in a loop (#32375)

---
 src/libraries/System.Private.Uri/src/System/IriHelper.cs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/libraries/System.Private.Uri/src/System/IriHelper.cs b/src/libraries/System.Private.Uri/src/System/IriHelper.cs
index bb18ff9485c94..c2d6a0b91703c 100644
--- a/src/libraries/System.Private.Uri/src/System/IriHelper.cs
+++ b/src/libraries/System.Private.Uri/src/System/IriHelper.cs
@@ -112,6 +112,8 @@ internal static unsafe string EscapeUnescapeIri(char* pInput, int start, int end
             int next = start;
             char ch;
 
+            Span<byte> maxUtf8EncodedSpan = stackalloc byte[4];
+
             for (; next < end; ++next)
             {
                 if ((ch = pInput[next]) == '%')
@@ -235,8 +237,6 @@ internal static unsafe string EscapeUnescapeIri(char* pInput, int start, int end
 
                     if (escape)
                     {
-                        Span<byte> encodedBytes = stackalloc byte[4];
-
                         Rune rune;
                         if (surrogatePair)
                         {
@@ -247,8 +247,8 @@ internal static unsafe string EscapeUnescapeIri(char* pInput, int start, int end
                             rune = Rune.ReplacementChar;
                         }
 
-                        int bytesWritten = rune.EncodeToUtf8(encodedBytes);
-                        encodedBytes = encodedBytes.Slice(0, bytesWritten);
+                        int bytesWritten = rune.EncodeToUtf8(maxUtf8EncodedSpan);
+                        Span<byte> encodedBytes = maxUtf8EncodedSpan.Slice(0, bytesWritten);
 
                         foreach (byte b in encodedBytes)
                         {