From c436802bcefcdac53cefe7b7c40d06e56884e132 Mon Sep 17 00:00:00 2001
From: Ashutosh Mehra <asmehra@openjdk.org>
Date: Mon, 23 Mar 2026 14:17:11 +0000
Subject: [PATCH] 8380168: Obsolete unused flag UseNewLongLShift

Reviewed-by: kvn, stuefe
---
 src/hotspot/cpu/x86/globals_x86.hpp     | 3 ---
 src/hotspot/cpu/x86/vm_version_x86.cpp  | 4 ----
 src/hotspot/share/runtime/arguments.cpp | 2 ++
 3 files changed, 2 insertions(+), 7 deletions(-)

diff --git a/src/hotspot/cpu/x86/globals_x86.hpp b/src/hotspot/cpu/x86/globals_x86.hpp
index 084793dc262..6de46752790 100644
--- a/src/hotspot/cpu/x86/globals_x86.hpp
+++ b/src/hotspot/cpu/x86/globals_x86.hpp
@@ -117,9 +117,6 @@ define_pd_global(intx, InitArrayShortSize, 8*BytesPerLong);
   product(bool, UseIncDec, true, DIAGNOSTIC,                                \
           "Use INC, DEC instructions on x86")                               \
                                                                             \
-  product(bool, UseNewLongLShift, false,                                    \
-          "Use optimized bitwise shift left")                               \
-                                                                            \
   product(bool, UseAddressNop, false,                                       \
           "Use '0F 1F [addr]' NOP instructions on x86 cpus")                \
                                                                             \
diff --git a/src/hotspot/cpu/x86/vm_version_x86.cpp b/src/hotspot/cpu/x86/vm_version_x86.cpp
index 747d662f668..4301bd328d6 100644
--- a/src/hotspot/cpu/x86/vm_version_x86.cpp
+++ b/src/hotspot/cpu/x86/vm_version_x86.cpp
@@ -1525,10 +1525,6 @@ void VM_Version::get_processor_features() {
       // Use it on new AMD cpus starting from Opteron.
       UseAddressNop = true;
     }
-    if (supports_sse2() && FLAG_IS_DEFAULT(UseNewLongLShift)) {
-      // Use it on new AMD cpus starting from Opteron.
-      UseNewLongLShift = true;
-    }
     if (FLAG_IS_DEFAULT(UseXmmLoadAndClearUpper)) {
       if (supports_sse4a()) {
         UseXmmLoadAndClearUpper = true; // use movsd only on '10h' Opteron
diff --git a/src/hotspot/share/runtime/arguments.cpp b/src/hotspot/share/runtime/arguments.cpp
index b853349242c..dac34017e45 100644
--- a/src/hotspot/share/runtime/arguments.cpp
+++ b/src/hotspot/share/runtime/arguments.cpp
@@ -555,6 +555,8 @@ static SpecialFlag const special_jvm_flags[] = {
   { "NeverActAsServerClassMachine", JDK_Version::jdk(26),  JDK_Version::jdk(27), JDK_Version::jdk(28) },
   { "AlwaysActAsServerClassMachine", JDK_Version::jdk(26),  JDK_Version::jdk(27), JDK_Version::jdk(28) },
   { "UseXMMForArrayCopy",           JDK_Version::undefined(), JDK_Version::jdk(27), JDK_Version::jdk(28) },
+  { "UseNewLongLShift",             JDK_Version::undefined(), JDK_Version::jdk(27), JDK_Version::jdk(28) },
+
 #ifdef ASSERT
   { "DummyObsoleteTestFlag",        JDK_Version::undefined(), JDK_Version::jdk(18), JDK_Version::undefined() },
 #endif