Merge remote-tracking branch 'origin/fix/dynarmic-faster-regalloc' into test/linux-all-prs-plus

2 files changed, 16 insertions, 7 deletions

diff --git a/src/dynarmic/src/dynarmic/backend/x64/reg_alloc.cpp b/src/dynarmic/src/dynarmic/backend/x64/reg_alloc.cpp
index 5a828839c1..4f3d253441 100644
--- a/src/dynarmic/src/dynarmic/backend/x64/reg_alloc.cpp
+++ b/src/dynarmic/src/dynarmic/backend/x64/reg_alloc.cpp
@@ -465,22 +465,24 @@ std::optional<HostLoc> RegAlloc::ValueLocation(const IR::Inst* value) const noex
     return std::nullopt;
 }
 
+// The checks that scan every location for def_inst are debug-only: per IR instruction they cost as
+// much as the rest of register allocation.
 void RegAlloc::DefineValueImpl(BlockOfCode& code, IR::Inst* def_inst, HostLoc host_loc) noexcept {
-    ASSERT(!ValueLocation(def_inst) && "def_inst has already been defined");
+    DEBUG_ASSERT(!ValueLocation(def_inst) && "def_inst has already been defined");
     LocInfo(host_loc).AddValue(host_loc, def_inst);
-    ASSERT(*ValueLocation(def_inst) == host_loc);
+    DEBUG_ASSERT(*ValueLocation(def_inst) == host_loc);
 }
 
 void RegAlloc::DefineValueImpl(BlockOfCode& code, IR::Inst* def_inst, const IR::Value& use_inst) noexcept {
-    ASSERT(!ValueLocation(def_inst) && "def_inst has already been defined");
+    DEBUG_ASSERT(!ValueLocation(def_inst) && "def_inst has already been defined");
     if (use_inst.IsImmediate()) {
         const HostLoc location = ScratchImpl(code, gpr_order);
         DefineValueImpl(code, def_inst, location);
         LoadImmediate(code, use_inst, location);
     } else {
-        ASSERT(ValueLocation(use_inst.GetInst()) && "use_inst must already be defined");
-        const HostLoc location = *ValueLocation(use_inst.GetInst());
-        DefineValueImpl(code, def_inst, location);
+        const auto location = ValueLocation(use_inst.GetInst());
+        ASSERT(location && "use_inst must already be defined");
+        DefineValueImpl(code, def_inst, *location);
     }
 }
 
diff --git a/src/dynarmic/src/dynarmic/backend/x64/reg_alloc.h b/src/dynarmic/src/dynarmic/backend/x64/reg_alloc.h
index 455c6a970a..0cad07796c 100644
--- a/src/dynarmic/src/dynarmic/backend/x64/reg_alloc.h
+++ b/src/dynarmic/src/dynarmic/backend/x64/reg_alloc.h
@@ -65,6 +65,11 @@ public:
     }
     void ReleaseOne() noexcept;
     void ReleaseAll() noexcept;
+    /// True when ReleaseAll would change nothing, as for most of the spill slots most of the time.
+    inline bool IsReleased() const noexcept {
+        return current_references == 0 && is_being_used_count == 0 && !is_scratch && !is_set_last_use &&
+               (total_uses != accumulated_uses || (values.empty() && total_uses == 0 && max_bit_width == 0));
+    }
     constexpr size_t GetMaxBitWidth() const noexcept { return 1 << max_bit_width; }
     void AddValue(HostLoc loc, IR::Inst* inst) noexcept;
     /// Checks if the given instruction is in our values set
@@ -201,8 +206,10 @@ public:
     void ReleaseStackSpace(BlockOfCode& code, const size_t stack_space) noexcept;
 
     inline void EndOfAllocScope() noexcept {
+        // After every IR instruction: skip the locations it left alone.
         for (auto& iter : hostloc_info)
-            iter.ReleaseAll();
+            if (!iter.IsReleased())
+                iter.ReleaseAll();
     }
     inline void AssertNoMoreUses() noexcept {
         ASSERT(std::all_of(hostloc_info.begin(), hostloc_info.end(), [](const auto& i) noexcept { return i.IsEmpty(); }));