diff --git a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
index 546db318c17d5..16be7d5012708 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUAttributor.cpp
@@ -799,7 +799,31 @@ AAAMDAttributes &AAAMDAttributes::createForPosition(const IRPosition &IRP,
   llvm_unreachable("AAAMDAttributes is only valid for function position");
 }
 
-/// Base class to derive different size ranges.
+/// Merge two range states and indicate changes. The range can apply to
+/// flat-workgroup-size and waves-per-eu attributes. The growth/merge of these
+/// two attributes is neither a union nor an intersection. Instead, it follows
+/// the rule below:
+///
+/// Lower = max(S.Lower, R.Lower)
+/// Upper = max(S.Upper, R.Upper)
+ChangeStatus mergeRangeStateAndIndicateChange(IntegerRangeState &S,
+                                              const IntegerRangeState &R) {
+  auto Assumed = S.getAssumed();
+  unsigned Min = R.getAssumed().getLower().getZExtValue();
+  unsigned Max = R.getAssumed().getUpper().getZExtValue();
+  Min = std::max(Min, static_cast<unsigned>(Assumed.getLower().getZExtValue()));
+  Max = std::max(Max, static_cast<unsigned>(Assumed.getUpper().getZExtValue()));
+  ConstantRange Range(APInt(32, Min), APInt(32, Max));
+  IntegerRangeState RangeState(Range);
+  S = RangeState;
+  return S == Assumed ? ChangeStatus::UNCHANGED : ChangeStatus::CHANGED;
+}
+
+/// Base class for deriving different size ranges. This size range is
+/// specifically intended for flat-workgroup-size and waves-per-eu attributes.
+/// Therefore, updating the attribute should use
+/// \p mergeRangeStateAndIndicateChange. Given this, the attribute may not be
+/// applicable to other potential size ranges in the future.
 struct AAAMDSizeRangeAttribute
     : public StateWrapper<IntegerRangeState, AbstractAttribute, uint32_t> {
   using Base = StateWrapper<IntegerRangeState, AbstractAttribute, uint32_t>;
@@ -826,8 +850,8 @@ struct AAAMDSizeRangeAttribute
       if (!CallerInfo || !CallerInfo->isValidState())
         return false;
 
-      Change |=
-          clampStateAndIndicateChange(this->getState(), CallerInfo->getState());
+      Change |= mergeRangeStateAndIndicateChange(this->getState(),
+                                                 CallerInfo->getState());
 
       return true;
     };
@@ -903,15 +927,14 @@ struct AAAMDFlatWorkGroupSize : public AAAMDSizeRangeAttribute {
       }
     }
 
-    // We don't want to directly clamp the state if it's the max range because
+    // We don't want to directly merge the state if it's the max range because
     // that is basically the worst state.
     if (Range == MaxRange)
       return;
 
     auto [Min, Max] = Range;
     ConstantRange CR(APInt(32, Min), APInt(32, Max + 1));
-    IntegerRangeState IRS(CR);
-    clampStateAndIndicateChange(this->getState(), IRS);
+    this->getState() = IntegerRangeState(CR);
 
     if (HasAttr || AMDGPU::isEntryFunctionCC(F->getCallingConv()))
       indicateOptimisticFixpoint();
diff --git a/llvm/test/CodeGen/AMDGPU/propagate-flat-work-group-size.ll b/llvm/test/CodeGen/AMDGPU/propagate-flat-work-group-size.ll
index 1afd31c6d45e7..0a3121f9de167 100644
--- a/llvm/test/CodeGen/AMDGPU/propagate-flat-work-group-size.ll
+++ b/llvm/test/CodeGen/AMDGPU/propagate-flat-work-group-size.ll
@@ -86,7 +86,7 @@ define internal void @flat_group_512_1024() #4 {
 
 define amdgpu_kernel void @kernel_128_512() #5 {
 ; CHECK-LABEL: define {{[^@]+}}@kernel_128_512
-; CHECK-SAME: () #[[ATTR2]] {
+; CHECK-SAME: () #[[ATTR6:[0-9]+]] {
 ; CHECK-NEXT:    call void @default_to_128_512()
 ; CHECK-NEXT:    call void @flat_group_64_64()
 ; CHECK-NEXT:    ret void
@@ -98,7 +98,7 @@ define amdgpu_kernel void @kernel_128_512() #5 {
 
 define amdgpu_kernel void @kernel_512_512() #6 {
 ; CHECK-LABEL: define {{[^@]+}}@kernel_512_512
-; CHECK-SAME: () #[[ATTR6:[0-9]+]] {
+; CHECK-SAME: () #[[ATTR2]] {
 ; CHECK-NEXT:    call void @default_to_128_512()
 ; CHECK-NEXT:    call void @flat_group_512_1024()
 ; CHECK-NEXT:    ret void
@@ -111,7 +111,7 @@ define amdgpu_kernel void @kernel_512_512() #6 {
 ; Called from kernels with 128,256 and 64,128 => 64,256
 define internal void @default_to_64_256() {
 ; CHECK-LABEL: define {{[^@]+}}@default_to_64_256
-; CHECK-SAME: () #[[ATTR7:[0-9]+]] {
+; CHECK-SAME: () #[[ATTR4]] {
 ; CHECK-NEXT:    ret void
 ;
   ret void
@@ -153,7 +153,7 @@ define internal void @merge_cycle_1() #3 {
 
 define amdgpu_kernel void @kernel_64_256() #7 {
 ; CHECK-LABEL: define {{[^@]+}}@kernel_64_256
-; CHECK-SAME: () #[[ATTR7]] {
+; CHECK-SAME: () #[[ATTR7:[0-9]+]] {
 ; CHECK-NEXT:    call void @merge_cycle_0()
 ; CHECK-NEXT:    call void @default_captured_address()
 ; CHECK-NEXT:    call void @externally_visible_default()
@@ -205,11 +205,11 @@ attributes #7 = { "amdgpu-flat-work-group-size"="64,256" }
 ;.
 ; CHECK: attributes #[[ATTR0]] = { "amdgpu-flat-work-group-size"="1,256" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "uniform-work-group-size"="false" }
 ; CHECK: attributes #[[ATTR1]] = { "amdgpu-flat-work-group-size"="64,128" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "uniform-work-group-size"="false" }
-; CHECK: attributes #[[ATTR2]] = { "amdgpu-flat-work-group-size"="128,512" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "amdgpu-waves-per-eu"="2,10" "uniform-work-group-size"="false" }
+; CHECK: attributes #[[ATTR2]] = { "amdgpu-flat-work-group-size"="512,512" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "amdgpu-waves-per-eu"="2,10" "uniform-work-group-size"="false" }
 ; CHECK: attributes #[[ATTR3]] = { "amdgpu-flat-work-group-size"="64,64" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "uniform-work-group-size"="false" }
 ; CHECK: attributes #[[ATTR4]] = { "amdgpu-flat-work-group-size"="128,256" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "uniform-work-group-size"="false" }
 ; CHECK: attributes #[[ATTR5]] = { "amdgpu-flat-work-group-size"="512,1024" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "amdgpu-waves-per-eu"="4,10" "uniform-work-group-size"="false" }
-; CHECK: attributes #[[ATTR6]] = { "amdgpu-flat-work-group-size"="512,512" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "amdgpu-waves-per-eu"="2,10" "uniform-work-group-size"="false" }
+; CHECK: attributes #[[ATTR6]] = { "amdgpu-flat-work-group-size"="128,512" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "amdgpu-waves-per-eu"="2,10" "uniform-work-group-size"="false" }
 ; CHECK: attributes #[[ATTR7]] = { "amdgpu-flat-work-group-size"="64,256" "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "uniform-work-group-size"="false" }
 ; CHECK: attributes #[[ATTR8]] = { "amdgpu-no-agpr" "amdgpu-no-completion-action" "amdgpu-no-default-queue" "amdgpu-no-dispatch-id" "amdgpu-no-dispatch-ptr" "amdgpu-no-flat-scratch-init" "amdgpu-no-heap-ptr" "amdgpu-no-hostcall-ptr" "amdgpu-no-implicitarg-ptr" "amdgpu-no-lds-kernel-id" "amdgpu-no-multigrid-sync-arg" "amdgpu-no-queue-ptr" "amdgpu-no-workgroup-id-x" "amdgpu-no-workgroup-id-y" "amdgpu-no-workgroup-id-z" "amdgpu-no-workitem-id-x" "amdgpu-no-workitem-id-y" "amdgpu-no-workitem-id-z" "uniform-work-group-size"="false" }
 ;.