diff --git a/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.h b/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.h
--- a/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.h
+++ b/llvm/lib/Target/AMDGPU/SIMachineFunctionInfo.h
@@ -17,6 +17,7 @@
 #include "AMDGPUMachineFunction.h"
 #include "MCTargetDesc/AMDGPUMCTargetDesc.h"
 #include "SIInstrInfo.h"
+#include "llvm/ADT/MapVector.h"
 #include "llvm/CodeGen/MIRYamlMapping.h"
 #include "llvm/CodeGen/PseudoSourceValue.h"
 #include "llvm/Support/raw_ostream.h"
@@ -463,7 +464,7 @@
 
   // Map WWM VGPR to a stack slot that is used to save/restore it in the
   // prolog/epilog.
-  SmallDenseMap<Register, Optional<int>> WWMReservedRegs;
+  MapVector<Register, Optional<int>> WWMReservedRegs;
 
 private:
   // Track VGPR + wave index for each subregister of the SGPR spilled to
diff --git a/llvm/test/CodeGen/AMDGPU/wwm-reserved-spill.ll b/llvm/test/CodeGen/AMDGPU/wwm-reserved-spill.ll
--- a/llvm/test/CodeGen/AMDGPU/wwm-reserved-spill.ll
+++ b/llvm/test/CodeGen/AMDGPU/wwm-reserved-spill.ll
@@ -7,9 +7,9 @@
 ; GFX9-O0:       ; %bb.0:
 ; GFX9-O0-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
 ; GFX9-O0-NEXT:    s_or_saveexec_b64 s[8:9], -1
-; GFX9-O0-NEXT:    buffer_store_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Spill
-; GFX9-O0-NEXT:    buffer_store_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    buffer_store_dword v0, off, s[0:3], s32 ; 4-byte Folded Spill
+; GFX9-O0-NEXT:    buffer_store_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
+; GFX9-O0-NEXT:    buffer_store_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    s_mov_b64 exec, s[8:9]
 ; GFX9-O0-NEXT:    s_mov_b32 s8, s7
 ; GFX9-O0-NEXT:    s_mov_b32 s9, s6
@@ -55,9 +55,9 @@
 ; GFX9-O0-NEXT:    v_and_b32_e32 v3, v3, v4
 ; GFX9-O0-NEXT:    buffer_store_dword v3, off, s[4:7], s8 offset:4
 ; GFX9-O0-NEXT:    s_or_saveexec_b64 s[4:5], -1
-; GFX9-O0-NEXT:    buffer_load_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Reload
-; GFX9-O0-NEXT:    buffer_load_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
 ; GFX9-O0-NEXT:    buffer_load_dword v0, off, s[0:3], s32 ; 4-byte Folded Reload
+; GFX9-O0-NEXT:    buffer_load_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
+; GFX9-O0-NEXT:    buffer_load_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Reload
 ; GFX9-O0-NEXT:    s_mov_b64 exec, s[4:5]
 ; GFX9-O0-NEXT:    s_waitcnt vmcnt(0)
 ; GFX9-O0-NEXT:    s_setpc_b64 s[30:31]
@@ -66,11 +66,11 @@
 ; GFX9-O3:       ; %bb.0:
 ; GFX9-O3-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
 ; GFX9-O3-NEXT:    s_or_saveexec_b64 s[8:9], -1
+; GFX9-O3-NEXT:    buffer_store_dword v0, off, s[0:3], s32 ; 4-byte Folded Spill
 ; GFX9-O3-NEXT:    buffer_store_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
 ; GFX9-O3-NEXT:    buffer_store_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Spill
 ; GFX9-O3-NEXT:    s_waitcnt vmcnt(0)
 ; GFX9-O3-NEXT:    buffer_store_dword v3, off, s[0:3], s32 offset:12 ; 4-byte Folded Spill
-; GFX9-O3-NEXT:    buffer_store_dword v0, off, s[0:3], s32 ; 4-byte Folded Spill
 ; GFX9-O3-NEXT:    s_mov_b64 exec, s[8:9]
 ; GFX9-O3-NEXT:    buffer_load_dwordx2 v[2:3], off, s[4:7], 0
 ; GFX9-O3-NEXT:    s_or_saveexec_b64 s[8:9], -1
@@ -98,13 +98,12 @@
 ; GFX9-O3-NEXT:    v_and_b32_e32 v4, 2, v4
 ; GFX9-O3-NEXT:    buffer_store_dword v4, off, s[4:7], 0 offset:4
 ; GFX9-O3-NEXT:    s_or_saveexec_b64 s[4:5], -1
+; GFX9-O3-NEXT:    buffer_load_dword v0, off, s[0:3], s32 ; 4-byte Folded Reload
 ; GFX9-O3-NEXT:    buffer_load_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
 ; GFX9-O3-NEXT:    s_nop 0
 ; GFX9-O3-NEXT:    buffer_load_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Reload
 ; GFX9-O3-NEXT:    s_nop 0
 ; GFX9-O3-NEXT:    buffer_load_dword v3, off, s[0:3], s32 offset:12 ; 4-byte Folded Reload
-; GFX9-O3-NEXT:    s_nop 0
-; GFX9-O3-NEXT:    buffer_load_dword v0, off, s[0:3], s32 ; 4-byte Folded Reload
 ; GFX9-O3-NEXT:    s_mov_b64 exec, s[4:5]
 ; GFX9-O3-NEXT:    s_waitcnt vmcnt(0)
 ; GFX9-O3-NEXT:    s_setpc_b64 s[30:31]
@@ -237,8 +236,8 @@
 ; GFX9-O3:       ; %bb.0: ; %entry
 ; GFX9-O3-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
 ; GFX9-O3-NEXT:    s_or_saveexec_b64 s[8:9], -1
-; GFX9-O3-NEXT:    buffer_store_dword v2, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
 ; GFX9-O3-NEXT:    buffer_store_dword v1, off, s[0:3], s32 ; 4-byte Folded Spill
+; GFX9-O3-NEXT:    buffer_store_dword v2, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
 ; GFX9-O3-NEXT:    buffer_store_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Spill
 ; GFX9-O3-NEXT:    s_waitcnt vmcnt(0)
 ; GFX9-O3-NEXT:    buffer_store_dword v3, off, s[0:3], s32 offset:12 ; 4-byte Folded Spill
@@ -279,8 +278,8 @@
 ; GFX9-O3-NEXT:    v_and_b32_e32 v0, 2, v0
 ; GFX9-O3-NEXT:    buffer_store_dword v0, off, s[4:7], 0 offset:4
 ; GFX9-O3-NEXT:    s_or_saveexec_b64 s[4:5], -1
-; GFX9-O3-NEXT:    buffer_load_dword v2, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
 ; GFX9-O3-NEXT:    buffer_load_dword v1, off, s[0:3], s32 ; 4-byte Folded Reload
+; GFX9-O3-NEXT:    buffer_load_dword v2, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
 ; GFX9-O3-NEXT:    s_nop 0
 ; GFX9-O3-NEXT:    buffer_load_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Reload
 ; GFX9-O3-NEXT:    s_nop 0
@@ -340,8 +339,8 @@
 ; GFX9-O0-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
 ; GFX9-O0-NEXT:    s_or_saveexec_b64 s[10:11], -1
 ; GFX9-O0-NEXT:    buffer_store_dword v3, off, s[0:3], s32 offset:8 ; 4-byte Folded Spill
-; GFX9-O0-NEXT:    buffer_store_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    buffer_store_dword v2, off, s[0:3], s32 ; 4-byte Folded Spill
+; GFX9-O0-NEXT:    buffer_store_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    s_mov_b64 exec, s[10:11]
 ; GFX9-O0-NEXT:    v_writelane_b32 v3, s33, 7
 ; GFX9-O0-NEXT:    s_mov_b32 s33, s32
@@ -390,8 +389,8 @@
 ; GFX9-O0-NEXT:    v_readlane_b32 s33, v3, 7
 ; GFX9-O0-NEXT:    s_or_saveexec_b64 s[4:5], -1
 ; GFX9-O0-NEXT:    buffer_load_dword v3, off, s[0:3], s32 offset:8 ; 4-byte Folded Reload
-; GFX9-O0-NEXT:    buffer_load_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
 ; GFX9-O0-NEXT:    buffer_load_dword v2, off, s[0:3], s32 ; 4-byte Folded Reload
+; GFX9-O0-NEXT:    buffer_load_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
 ; GFX9-O0-NEXT:    s_mov_b64 exec, s[4:5]
 ; GFX9-O0-NEXT:    s_waitcnt vmcnt(0)
 ; GFX9-O0-NEXT:    s_setpc_b64 s[30:31]
@@ -400,8 +399,8 @@
 ; GFX9-O3:       ; %bb.0:
 ; GFX9-O3-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
 ; GFX9-O3-NEXT:    s_or_saveexec_b64 s[10:11], -1
-; GFX9-O3-NEXT:    buffer_store_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
 ; GFX9-O3-NEXT:    buffer_store_dword v2, off, s[0:3], s32 ; 4-byte Folded Spill
+; GFX9-O3-NEXT:    buffer_store_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
 ; GFX9-O3-NEXT:    s_mov_b64 exec, s[10:11]
 ; GFX9-O3-NEXT:    s_mov_b32 s14, s33
 ; GFX9-O3-NEXT:    s_mov_b32 s33, s32
@@ -425,8 +424,8 @@
 ; GFX9-O3-NEXT:    s_sub_u32 s32, s32, 0x400
 ; GFX9-O3-NEXT:    s_mov_b32 s33, s14
 ; GFX9-O3-NEXT:    s_or_saveexec_b64 s[4:5], -1
-; GFX9-O3-NEXT:    buffer_load_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
 ; GFX9-O3-NEXT:    buffer_load_dword v2, off, s[0:3], s32 ; 4-byte Folded Reload
+; GFX9-O3-NEXT:    buffer_load_dword v1, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
 ; GFX9-O3-NEXT:    s_mov_b64 exec, s[4:5]
 ; GFX9-O3-NEXT:    s_waitcnt vmcnt(0)
 ; GFX9-O3-NEXT:    s_setpc_b64 s[10:11]
@@ -530,8 +529,10 @@
 ; GFX9-O0-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
 ; GFX9-O0-NEXT:    s_or_saveexec_b64 s[10:11], -1
 ; GFX9-O0-NEXT:    buffer_store_dword v11, off, s[0:3], s32 offset:40 ; 4-byte Folded Spill
+; GFX9-O0-NEXT:    buffer_store_dword v9, off, s[0:3], s32 ; 4-byte Folded Spill
+; GFX9-O0-NEXT:    s_waitcnt vmcnt(0)
+; GFX9-O0-NEXT:    buffer_store_dword v10, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    buffer_store_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Spill
-; GFX9-O0-NEXT:    buffer_store_dword v4, off, s[0:3], s32 offset:32 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    buffer_store_dword v3, off, s[0:3], s32 offset:12 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    s_waitcnt vmcnt(0)
 ; GFX9-O0-NEXT:    buffer_store_dword v4, off, s[0:3], s32 offset:16 ; 4-byte Folded Spill
@@ -539,9 +540,7 @@
 ; GFX9-O0-NEXT:    buffer_store_dword v2, off, s[0:3], s32 offset:24 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    s_waitcnt vmcnt(0)
 ; GFX9-O0-NEXT:    buffer_store_dword v3, off, s[0:3], s32 offset:28 ; 4-byte Folded Spill
-; GFX9-O0-NEXT:    buffer_store_dword v9, off, s[0:3], s32 ; 4-byte Folded Spill
-; GFX9-O0-NEXT:    s_waitcnt vmcnt(0)
-; GFX9-O0-NEXT:    buffer_store_dword v10, off, s[0:3], s32 offset:4 ; 4-byte Folded Spill
+; GFX9-O0-NEXT:    buffer_store_dword v4, off, s[0:3], s32 offset:32 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    buffer_store_dword v5, off, s[0:3], s32 offset:36 ; 4-byte Folded Spill
 ; GFX9-O0-NEXT:    s_mov_b64 exec, s[10:11]
 ; GFX9-O0-NEXT:    v_writelane_b32 v11, s33, 9
@@ -616,8 +615,12 @@
 ; GFX9-O0-NEXT:    v_readlane_b32 s33, v11, 9
 ; GFX9-O0-NEXT:    s_or_saveexec_b64 s[4:5], -1
 ; GFX9-O0-NEXT:    buffer_load_dword v11, off, s[0:3], s32 offset:40 ; 4-byte Folded Reload
+; GFX9-O0-NEXT:    s_nop 0
+; GFX9-O0-NEXT:    buffer_load_dword v9, off, s[0:3], s32 ; 4-byte Folded Reload
+; GFX9-O0-NEXT:    s_nop 0
+; GFX9-O0-NEXT:    buffer_load_dword v10, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
+; GFX9-O0-NEXT:    s_nop 0
 ; GFX9-O0-NEXT:    buffer_load_dword v2, off, s[0:3], s32 offset:8 ; 4-byte Folded Reload
-; GFX9-O0-NEXT:    buffer_load_dword v4, off, s[0:3], s32 offset:32 ; 4-byte Folded Reload
 ; GFX9-O0-NEXT:    s_nop 0
 ; GFX9-O0-NEXT:    buffer_load_dword v3, off, s[0:3], s32 offset:12 ; 4-byte Folded Reload
 ; GFX9-O0-NEXT:    s_nop 0
@@ -629,10 +632,7 @@
 ; GFX9-O0-NEXT:    s_nop 0
 ; GFX9-O0-NEXT:    buffer_load_dword v3, off, s[0:3], s32 offset:28 ; 4-byte Folded Reload
 ; GFX9-O0-NEXT:    s_nop 0
-; GFX9-O0-NEXT:    buffer_load_dword v9, off, s[0:3], s32 ; 4-byte Folded Reload
-; GFX9-O0-NEXT:    s_nop 0
-; GFX9-O0-NEXT:    buffer_load_dword v10, off, s[0:3], s32 offset:4 ; 4-byte Folded Reload
-; GFX9-O0-NEXT:    s_nop 0
+; GFX9-O0-NEXT:    buffer_load_dword v4, off, s[0:3], s32 offset:32 ; 4-byte Folded Reload
 ; GFX9-O0-NEXT:    buffer_load_dword v5, off, s[0:3], s32 offset:36 ; 4-byte Folded Reload
 ; GFX9-O0-NEXT:    s_mov_b64 exec, s[4:5]
 ; GFX9-O0-NEXT:    s_waitcnt vmcnt(0)