diff --git a/llvm/include/llvm/Frontend/OpenMP/OMPConstants.h b/llvm/include/llvm/Frontend/OpenMP/OMPConstants.h
--- a/llvm/include/llvm/Frontend/OpenMP/OMPConstants.h
+++ b/llvm/include/llvm/Frontend/OpenMP/OMPConstants.h
@@ -41,12 +41,21 @@
 #include "llvm/Frontend/OpenMP/OMPKinds.def"
 
 enum class ICVInitValue {
-#define ICV_DATA_ENV(Enum, Name, EnvVar, Init) Init,
+#define ICV_INIT_VALUE(Enum, Name) Enum,
 #include "llvm/Frontend/OpenMP/OMPKinds.def"
 };
 
-#define ICV_DATA_ENV(Enum, Name, EnvVar, Init)                                 \
-  constexpr auto Init = omp::ICVInitValue::Init;
+#define ICV_INIT_VALUE(Enum, Name)                                             \
+  constexpr auto Enum = omp::ICVInitValue::Enum;
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
+
+enum class ICVInterferenceKind {
+#define ICV_INTERFERENCE_KIND(Enum, Name) Enum,
+#include "llvm/Frontend/OpenMP/OMPKinds.def"
+};
+
+#define ICV_INTERFERENCE_KIND(Enum, Name)                                      \
+  constexpr auto Enum = omp::ICVInterferenceKind::Enum;
 #include "llvm/Frontend/OpenMP/OMPKinds.def"
 
 /// IDs for all omp runtime library (RTL) functions.
diff --git a/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def b/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def
--- a/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def
+++ b/llvm/include/llvm/Frontend/OpenMP/OMPKinds.def
@@ -144,6 +144,7 @@
 __OMP_TYPE(Void)
 __OMP_TYPE(Int1)
 __OMP_TYPE(Int8)
+__OMP_TYPE(Int16)
 __OMP_TYPE(Int32)
 __OMP_TYPE(Int64)
 __OMP_TYPE(Int8Ptr)
@@ -227,6 +228,33 @@
 ///
 ///{
 
+#ifndef ICV_INIT_VALUE
+#define ICV_INIT_VALUE(Enum, Name)
+#endif
+
+#define __ICV_INIT_VALUE(Name) ICV_INIT_VALUE(ICV_##Name, #Name)
+
+__ICV_INIT_VALUE(ZERO)
+__ICV_INIT_VALUE(FALSE)
+__ICV_INIT_VALUE(IMPLEMENTATION_DEFINED)
+__ICV_INIT_VALUE(LAST)
+
+#undef __ICV_INIT_VALUE
+#undef ICV_INIT_VALUE
+
+#ifndef ICV_INTERFERENCE_KIND
+#define ICV_INTERFERENCE_KIND(Enum, Name)
+#endif
+
+#define __ICV_INTERFERENCE_KIND(Name)                                          \
+  ICV_INTERFERENCE_KIND(ICV_INTERFERENCE_KIND_##Name, Name)
+
+__ICV_INTERFERENCE_KIND(anything)
+__ICV_INTERFERENCE_KIND(nothing)
+
+#undef __ICV_INTERFERENCE_KIND
+#undef ICV_INTERFERENCE_KIND
+
 #ifndef ICV_DATA_ENV
 #define ICV_DATA_ENV(Enum, Name, EnvVarName, Init)
 #endif
@@ -237,18 +265,22 @@
 __ICV_DATA_ENV(nthreads, OMP_NUM_THREADS, ICV_IMPLEMENTATION_DEFINED)
 __ICV_DATA_ENV(active_levels, NONE, ICV_ZERO)
 __ICV_DATA_ENV(cancel, OMP_CANCELLATION, ICV_FALSE)
+__ICV_DATA_ENV(GPU_SPMD, NONE, ICV_FALSE)
 __ICV_DATA_ENV(__last, last, ICV_LAST)
 
 #undef __ICV_DATA_ENV
 #undef ICV_DATA_ENV
 
 #ifndef ICV_RT_SET
-#define ICV_RT_SET(Name, RTL)
+#define ICV_RT_SET(Name, RTL, ARGUMENT_NO, INTERFERNCE_KIND)
 #endif
 
-#define __ICV_RT_SET(Name, RTL) ICV_RT_SET(ICV_##Name, OMPRTL_##RTL)
+#define __ICV_RT_SET(Name, RTL, ARGUMENT_NO, INTERFERNCE_KIND)                 \
+  ICV_RT_SET(ICV_##Name, OMPRTL_##RTL, ARGUMENT_NO,                            \
+             ICV_INTERFERENCE_KIND_##INTERFERNCE_KIND)
 
-__ICV_RT_SET(nthreads, omp_set_num_threads)
+__ICV_RT_SET(nthreads, omp_set_num_threads, /* ArgumentNo */ 1, anything)
+__ICV_RT_SET(GPU_SPMD, __kmpc_spmd_kernel_init, /* ArgumentNo */ -1, nothing)
 
 #undef __ICV_RT_SET
 #undef ICV_RT_SET
@@ -262,6 +294,7 @@
 __ICV_RT_GET(nthreads, omp_get_max_threads)
 __ICV_RT_GET(active_levels, omp_get_active_level)
 __ICV_RT_GET(cancel, omp_get_cancellation)
+__ICV_RT_GET(GPU_SPMD, __kmpc_is_spmd_exec_mode)
 
 #undef __ICV_RT_GET
 #undef ICV_RT_GET
@@ -328,6 +361,9 @@
 __OMP_RTL(omp_set_schedule, false, Void, Int32, Int32)
 __OMP_RTL(omp_set_max_active_levels, false, Void, Int32)
 
+__OMP_RTL(__kmpc_is_spmd_exec_mode, false, Int8, )
+__OMP_RTL(__kmpc_spmd_kernel_init, false, Void, Int32, Int16, Int16)
+
 __OMP_RTL(__kmpc_master, false, Int32, IdentPtr, Int32)
 __OMP_RTL(__kmpc_end_master, false, Void, IdentPtr, Int32)
 __OMP_RTL(__kmpc_critical, false, Void, IdentPtr, Int32, KmpCriticalNamePtrTy)
diff --git a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
--- a/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
+++ b/llvm/lib/Transforms/IPO/OpenMPOpt.cpp
@@ -158,6 +158,13 @@
     /// Setter RTL function associated with this ICV.
     RuntimeFunction Setter;
 
+    /// Which argument of the setter defines the value.
+    int SetterArgNo;
+
+    /// Kind to describe how this ICV is impacted by calls, e.g., if the value
+    /// can change or not by an unknown call.
+    ICVInterferenceKind InterferenceKind;
+
     /// Getter RTL function associated with this ICV.
     RuntimeFunction Getter;
 
@@ -314,10 +321,12 @@
   /// Helper to initialize all internal control variable information for those
   /// defined in OMPKinds.def.
   void initializeInternalControlVars() {
-#define ICV_RT_SET(_Name, RTL)                                                 \
+#define ICV_RT_SET(_Name, RTL, ARGUMENT_NO, INTERFERENCE_KIND)                 \
   {                                                                            \
     auto &ICV = ICVs[_Name];                                                   \
     ICV.Setter = RTL;                                                          \
+    ICV.SetterArgNo = ARGUMENT_NO;                                             \
+    ICV.InterferenceKind = INTERFERENCE_KIND;                                  \
   }
 #define ICV_RT_GET(Name, RTL)                                                  \
   {                                                                            \
@@ -1237,9 +1246,7 @@
                   InternalControlVar::ICV___last>
       ICVValuesMap;
 
-  // Currently only nthreads is being tracked.
-  // this array will only grow with time.
-  InternalControlVar TrackableICVs[1] = {ICV_nthreads};
+  InternalControlVar TrackableICVs[2] = {ICV_nthreads, ICV_GPU_SPMD};
 
   ChangeStatus updateImpl(Attributor &A) override {
     ChangeStatus HasChanged = ChangeStatus::UNCHANGED;
@@ -1249,16 +1256,22 @@
     auto &OMPInfoCache = static_cast<OMPInformationCache &>(A.getInfoCache());
 
     for (InternalControlVar ICV : TrackableICVs) {
-      auto &SetterRFI = OMPInfoCache.RFIs[OMPInfoCache.ICVs[ICV].Setter];
+      auto &ICVInfo = OMPInfoCache.ICVs[ICV];
+      auto &SetterRFI = OMPInfoCache.RFIs[ICVInfo.Setter];
 
       auto TrackValues = [&](Use &U, Function &) {
         CallInst *CI = OpenMPOpt::getCallIfRegularCall(U);
         if (!CI)
           return false;
 
-        // FIXME: handle setters with more that 1 arguments.
-        /// Track new value.
-        if (ICVValuesMap[ICV].insert(ICVValue(CI, CI->getArgOperand(0))))
+        // Track new value.
+        Value *ICVIRValue;
+        if (ICVInfo.SetterArgNo >= 0)
+          ICVIRValue = CI->getArgOperand(ICVInfo.SetterArgNo);
+        else
+          ICVIRValue = ConstantInt::get(Type::getInt8Ty(CI->getContext()), 1);
+
+        if (ICVValuesMap[ICV].insert(ICVValue(CI, ICVIRValue)))
           HasChanged = ChangeStatus::CHANGED;
 
         return false;
@@ -1277,12 +1290,16 @@
 
     auto &ValuesSet = ICVValuesMap[ICV];
     auto &OMPInfoCache = static_cast<OMPInformationCache &>(A.getInfoCache());
-    auto &GetterRFI = OMPInfoCache.RFIs[OMPInfoCache.ICVs[ICV].Getter];
+    auto &ICVInfo = OMPInfoCache.ICVs[ICV];
+    auto &GetterRFI = OMPInfoCache.RFIs[ICVInfo.Getter];
 
     for (const auto &ICVVal : ValuesSet) {
       if (CurrBB == ICVVal.Inst->getParent()) {
         if (!ICVVal.Inst->comesBefore(I))
           continue;
+        // If nothing can interfere with this ICV, we don't need to check.
+        if (ICVInfo.InterferenceKind == ICV_INTERFERENCE_KIND_nothing)
+          return ICVVal.TrackedValue;
 
         // both instructions are in the same BB and at \p I we know the ICV
         // value.