diff --git a/Source/Core/Core/PowerPC/JitArm64/Jit.cpp b/Source/Core/Core/PowerPC/JitArm64/Jit.cpp
index 4a22d1c964..8555f2b5f2 100644
--- a/Source/Core/Core/PowerPC/JitArm64/Jit.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/Jit.cpp
@@ -694,6 +694,15 @@ void JitArm64::DoJit(u32 em_address, JitBlock* b, u32 nextPC)
     if (!SConfig::GetInstance().bEnableDebugging)
       js.downcountAmount += PatchEngine::GetSpeedhackCycles(js.compilerPC);
 
+    // Skip calling UpdateLastUsed for lmw/stmw - it usually hurts more than it helps
+    if (op.inst.OPCD != 46 && op.inst.OPCD != 47)
+      gpr.UpdateLastUsed(op.regsIn | op.regsOut);
+
+    BitSet32 fpr_used = op.fregsIn;
+    if (op.fregOut >= 0)
+      fpr_used[op.fregOut] = true;
+    fpr.UpdateLastUsed(fpr_used);
+
     // Gather pipe writes using a non-immediate address are discovered by profiling.
     bool gatherPipeIntCheck = js.fifoWriteAddresses.find(op.address) != js.fifoWriteAddresses.end();
 
diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_FloatingPoint.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_FloatingPoint.cpp
index 8a4eddaf5e..08e3d2ab9b 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_FloatingPoint.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_FloatingPoint.cpp
@@ -32,8 +32,11 @@ void JitArm64::fp_arith(UGeckoInstruction inst)
   bool use_c = op5 >= 25;  // fmul and all kind of fmaddXX
   bool use_b = op5 != 25;  // fmul uses no B
 
-  bool inputs_are_singles = fpr.IsSingle(a, !packed) && (!use_b || fpr.IsSingle(b, !packed)) &&
-                            (!use_c || fpr.IsSingle(c, !packed));
+  const auto inputs_are_singles_func = [&] {
+    return fpr.IsSingle(a, !packed) && (!use_b || fpr.IsSingle(b, !packed)) &&
+           (!use_c || fpr.IsSingle(c, !packed));
+  };
+  const bool inputs_are_singles = inputs_are_singles_func();
 
   ARM64Reg VA{}, VB{}, VC{}, VD{};
 
@@ -117,6 +120,9 @@ void JitArm64::fp_arith(UGeckoInstruction inst)
     }
   }
 
+  ASSERT_MSG(DYNA_REC, inputs_are_singles == inputs_are_singles_func(),
+             "Register allocation turned singles into doubles in the middle of fp_arith");
+
   if (single || packed)
     fpr.FixSinglePrecision(d);
 }
@@ -196,6 +202,9 @@ void JitArm64::fp_logic(UGeckoInstruction inst)
       break;
     }
   }
+
+  ASSERT_MSG(DYNA_REC, single == fpr.IsSingle(b, !packed),
+             "Register allocation turned singles into doubles in the middle of fp_logic");
 }
 
 void JitArm64::fselx(UGeckoInstruction inst)
@@ -209,6 +218,7 @@ void JitArm64::fselx(UGeckoInstruction inst)
   const u32 c = inst.FC;
   const u32 d = inst.FD;
 
+  const bool a_single = fpr.IsSingle(a, true);
   if (fpr.IsSingle(a, true))
   {
     const ARM64Reg VA = fpr.R(a, RegType::LowerPairSingle);
@@ -220,15 +230,20 @@ void JitArm64::fselx(UGeckoInstruction inst)
     m_float_emit.FCMPE(EncodeRegToDouble(VA));
   }
 
-  const bool single = fpr.IsSingle(b, true) && fpr.IsSingle(c, true);
-  const RegType type = single ? RegType::LowerPairSingle : RegType::LowerPair;
-  const auto reg_encoder = single ? EncodeRegToSingle : EncodeRegToDouble;
+  const bool b_and_c_singles = fpr.IsSingle(b, true) && fpr.IsSingle(c, true);
+  const RegType type = b_and_c_singles ? RegType::LowerPairSingle : RegType::LowerPair;
+  const auto reg_encoder = b_and_c_singles ? EncodeRegToSingle : EncodeRegToDouble;
 
   const ARM64Reg VB = fpr.R(b, type);
   const ARM64Reg VC = fpr.R(c, type);
   const ARM64Reg VD = fpr.RW(d, type);
 
   m_float_emit.FCSEL(reg_encoder(VD), reg_encoder(VC), reg_encoder(VB), CC_GE);
+
+  ASSERT_MSG(DYNA_REC,
+             a_single == fpr.IsSingle(a, true) &&
+                 b_and_c_singles == (fpr.IsSingle(b, true) && fpr.IsSingle(c, true)),
+             "Register allocation turned singles into doubles in the middle of fselx");
 }
 
 void JitArm64::frspx(UGeckoInstruction inst)
@@ -241,7 +256,8 @@ void JitArm64::frspx(UGeckoInstruction inst)
   const u32 b = inst.FB;
   const u32 d = inst.FD;
 
-  if (fpr.IsSingle(b, true))
+  const bool single = fpr.IsSingle(b, true);
+  if (single)
   {
     // Source is already in single precision, so no need to do anything but to copy to PSR1.
     const ARM64Reg VB = fpr.R(b, RegType::LowerPairSingle);
@@ -257,6 +273,9 @@ void JitArm64::frspx(UGeckoInstruction inst)
 
     m_float_emit.FCVT(32, 64, EncodeRegToDouble(VD), EncodeRegToDouble(VB));
   }
+
+  ASSERT_MSG(DYNA_REC, b == d || single == fpr.IsSingle(b, true),
+             "Register allocation turned singles into doubles in the middle of frspx");
 }
 
 void JitArm64::fcmpX(UGeckoInstruction inst)
@@ -320,6 +339,9 @@ void JitArm64::fcmpX(UGeckoInstruction inst)
     SetJumpTarget(continue3);
   }
   SetJumpTarget(continue1);
+
+  ASSERT_MSG(DYNA_REC, singles == (fpr.IsSingle(a, true) && fpr.IsSingle(b, true)),
+             "Register allocation turned singles into doubles in the middle of fcmpX");
 }
 
 void JitArm64::fctiwzx(UGeckoInstruction inst)
@@ -334,7 +356,7 @@ void JitArm64::fctiwzx(UGeckoInstruction inst)
   const bool single = fpr.IsSingle(b, true);
 
   const ARM64Reg VB = fpr.R(b, single ? RegType::LowerPairSingle : RegType::LowerPair);
-  const ARM64Reg VD = fpr.RW(d);
+  const ARM64Reg VD = fpr.RW(d, RegType::LowerPair);
 
   const ARM64Reg V0 = fpr.GetReg();
 
@@ -357,4 +379,7 @@ void JitArm64::fctiwzx(UGeckoInstruction inst)
   }
   m_float_emit.ORR(EncodeRegToDouble(VD), EncodeRegToDouble(VD), EncodeRegToDouble(V0));
   fpr.Unlock(V0);
+
+  ASSERT_MSG(DYNA_REC, b == d || single == fpr.IsSingle(b, true),
+             "Register allocation turned singles into doubles in the middle of fctiwzx");
 }
diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Paired.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Paired.cpp
index faa58e6ad0..00cd92c39b 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_Paired.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_Paired.cpp
@@ -66,6 +66,9 @@ void JitArm64::ps_mergeXX(UGeckoInstruction inst)
     ASSERT_MSG(DYNA_REC, 0, "ps_merge - invalid op");
     break;
   }
+
+  ASSERT_MSG(DYNA_REC, singles == (fpr.IsSingle(a) && fpr.IsSingle(b)),
+             "Register allocation turned singles into doubles in the middle of ps_mergeXX");
 }
 
 void JitArm64::ps_mulsX(UGeckoInstruction inst)
@@ -92,6 +95,9 @@ void JitArm64::ps_mulsX(UGeckoInstruction inst)
 
   m_float_emit.FMUL(size, reg_encoder(VD), reg_encoder(VA), reg_encoder(VC), upper ? 1 : 0);
 
+  ASSERT_MSG(DYNA_REC, singles == (fpr.IsSingle(a) && fpr.IsSingle(c)),
+             "Register allocation turned singles into doubles in the middle of ps_mulsX");
+
   fpr.FixSinglePrecision(d);
 }
 
@@ -250,6 +256,10 @@ void JitArm64::ps_maddXX(UGeckoInstruction inst)
     ASSERT_MSG(DYNA_REC, 0, "ps_madd - invalid op");
     break;
   }
+
+  ASSERT_MSG(DYNA_REC, singles == (fpr.IsSingle(a) && fpr.IsSingle(b) && fpr.IsSingle(c)),
+             "Register allocation turned singles into doubles in the middle of ps_maddXX");
+
   fpr.FixSinglePrecision(d);
 
   if (V0Q != INVALID_REG)
@@ -291,6 +301,9 @@ void JitArm64::ps_sel(UGeckoInstruction inst)
     m_float_emit.MOV(VD, V0);
     fpr.Unlock(V0Q);
   }
+
+  ASSERT_MSG(DYNA_REC, singles == (fpr.IsSingle(a) && fpr.IsSingle(b) && fpr.IsSingle(c)),
+             "Register allocation turned singles into doubles in the middle of ps_sel");
 }
 
 void JitArm64::ps_sumX(UGeckoInstruction inst)
@@ -330,6 +343,9 @@ void JitArm64::ps_sumX(UGeckoInstruction inst)
     m_float_emit.INS(size, VD, upper ? 1 : 0, V0, upper ? 1 : 0);
   }
 
+  ASSERT_MSG(DYNA_REC, singles == (fpr.IsSingle(a) && fpr.IsSingle(b) && fpr.IsSingle(c)),
+             "Register allocation turned singles into doubles in the middle of ps_sumX");
+
   fpr.FixSinglePrecision(d);
 
   fpr.Unlock(V0);
diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.cpp b/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.cpp
index 4a3f255c71..d0d861d992 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.cpp
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.cpp
@@ -41,10 +41,22 @@ ARM64Reg Arm64RegCache::GetReg()
   // Holy cow, how did you run out of registers?
   // We can't return anything reasonable in this case. Return INVALID_REG and watch the failure
   // happen
-  WARN_LOG_FMT(DYNA_REC, "All available registers are locked dumb dumb");
+  ASSERT_MSG(DYNA_REC, 0, "All available registers are locked!");
   return INVALID_REG;
 }
 
+void Arm64RegCache::UpdateLastUsed(BitSet32 regs_used)
+{
+  for (size_t i = 0; i < m_guest_registers.size(); ++i)
+  {
+    OpArg& reg = m_guest_registers[i];
+    if (i < 32 && regs_used[i])
+      reg.ResetLastUsed();
+    else
+      reg.IncrementLastUsed();
+  }
+}
+
 u32 Arm64RegCache::GetUnlockedRegisterCount() const
 {
   u32 unlocked_registers = 0;
diff --git a/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.h b/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.h
index b074001830..55c86bd4ab 100644
--- a/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.h
+++ b/Source/Core/Core/PowerPC/JitArm64/JitArm64_RegCache.h
@@ -140,6 +140,8 @@ public:
   // Requires unlocking after done
   Arm64Gen::ARM64Reg GetReg();
 
+  void UpdateLastUsed(BitSet32 regs_used);
+
   // Locks a register so a cache cannot use it
   // Useful for function calls
   template <typename T = Arm64Gen::ARM64Reg, typename... Args>
@@ -281,9 +283,9 @@ public:
 
   // Returns a guest register inside of a host register
   // Will dump an immediate to the host register as well
-  Arm64Gen::ARM64Reg R(size_t preg, RegType type = RegType::LowerPair);
+  Arm64Gen::ARM64Reg R(size_t preg, RegType type);
 
-  Arm64Gen::ARM64Reg RW(size_t preg, RegType type = RegType::LowerPair);
+  Arm64Gen::ARM64Reg RW(size_t preg, RegType type);
 
   BitSet32 GetCallerSavedUsed() const override;