From 0a2fecd7f25f6bae7c3dbda543d6661e6d4f8c64 Mon Sep 17 00:00:00 2001
From: "github-actions[bot]"
 <41898282+github-actions[bot]@users.noreply.github.com>
Date: Fri, 15 Mar 2024 14:40:06 -0700
Subject: [PATCH] [release/8.0-staging] disable optimizations for PopCount
 (#99832)

* disable optimizations for PopCount

avoid using an optimization which might fail on non-SSE4 cpus.

* remove whitespace for jit-format

---------

Co-authored-by: Manish Godse <61718172+mangod9@users.noreply.github.com>
---
 src/coreclr/jit/utils.cpp | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/coreclr/jit/utils.cpp b/src/coreclr/jit/utils.cpp
index 2e1c0a52a3d81b..4c9fe6479eca41 100644
--- a/src/coreclr/jit/utils.cpp
+++ b/src/coreclr/jit/utils.cpp
@@ -3192,6 +3192,11 @@ uint32_t BitOperations::Log2(uint64_t value)
 // Return Value:
 //    The population count (number of bits set) of value
 //
+#if defined(_MSC_VER)
+// Disable optimizations for PopCount to avoid the compiler from generating intrinsics
+// not supported on all platforms.
+#pragma optimize("", off)
+#endif // _MSC_VER
 uint32_t BitOperations::PopCount(uint32_t value)
 {
 #if defined(_MSC_VER)
@@ -3244,6 +3249,9 @@ uint32_t BitOperations::PopCount(uint64_t value)
     return static_cast<uint32_t>(result);
 #endif
 }
+#if defined(_MSC_VER)
+#pragma optimize("", on)
+#endif // _MSC_VER
 
 //------------------------------------------------------------------------
 // BitOperations::ReverseBits: Reverses the bits in an integer value