Restore 'computed goto' code generation for the VM loop on VS2022

CMakeLists.txt

@@ -166,12 +166,6 @@ if(LUAU_EXTERN_C)
     target_compile_definitions(Luau.CodeGen PUBLIC LUACODEGEN_API=extern\"C\")
 endif()
 
-if (CMAKE_CXX_COMPILER_ID STREQUAL "MSVC" AND MSVC_VERSION GREATER_EQUAL 1924)
-    # disable partial redundancy elimination which regresses interpreter codegen substantially in VS2022:
-    # https://developercommunity.visualstudio.com/t/performance-regression-on-a-complex-interpreter-lo/1631863
-    set_source_files_properties(VM/src/lvmexecute.cpp PROPERTIES COMPILE_FLAGS /d2ssa-pre-)
-endif()
-
 if (NOT MSVC)
     # disable support for math_errno which allows compilers to lower sqrt() into a single CPU instruction
     target_compile_options(Luau.VM PRIVATE -fno-math-errno)

Common/include/Luau/Common.h

@@ -1,5 +1,10 @@
 // This file is part of the Luau programming language and is licensed under MIT License; see LICENSE.txt for details
 #pragma once
+#ifdef __clang__
+#if __has_warning("-Wassume")
+#pragma clang diagnostic ignored "-Wassume"
+#endif
+#endif
 
 // Compiler codegen control macros
 #ifdef _MSC_VER
@@ -10,6 +15,7 @@
 #define LUAU_UNLIKELY(x) x
 #define LUAU_UNREACHABLE() __assume(false)
 #define LUAU_DEBUGBREAK() __debugbreak()
+#define LUAU_ASSUME(x) __assume(x)
 #else
 #define LUAU_NORETURN __attribute__((__noreturn__))
 #define LUAU_NOINLINE __attribute__((noinline))
@@ -18,6 +24,7 @@
 #define LUAU_UNLIKELY(x) __builtin_expect(x, 0)
 #define LUAU_UNREACHABLE() __builtin_unreachable()
 #define LUAU_DEBUGBREAK() __builtin_trap()
+#define LUAU_ASSUME(x)  (void)sizeof(!!(x))
 #endif
 
 // LUAU_FALLTHROUGH is a C++11-compatible alternative to [[fallthrough]] for use in the VM library
@@ -65,7 +72,7 @@ LUAU_NOINLINE inline int assertCallHandler(const char* expression, const char* f
 #define LUAU_ASSERT(expr) ((void)(!!(expr) || (Luau::assertCallHandler(#expr, __FILE__, __LINE__, __FUNCTION__) && (LUAU_DEBUGBREAK(), 0))))
 #define LUAU_ASSERTENABLED
 #else
-#define LUAU_ASSERT(expr) (void)sizeof(!!(expr))
+#define LUAU_ASSERT(expr) LUAU_ASSUME(expr)
 #endif
 
 namespace Luau

VM/src/lvmexecute.cpp

@@ -77,7 +77,7 @@ LUAU_DYNAMIC_FASTFLAG(LuauPopIncompleteCi)
             if (L->status != 0) \
             { \
                 L->ci->savedpc--; \
-                goto exit; \
+                return; \
             } \
         } \
     }
@@ -123,10 +123,12 @@ LUAU_DYNAMIC_FASTFLAG(LuauPopIncompleteCi)
 #if VM_USE_CGOTO
 #define VM_CASE(op) CASE_##op:
 #define VM_NEXT() goto*(SingleStep ? &&dispatch : kDispatchTable[LUAU_INSN_OP(*pc)])
+#define VM_START() VM_NEXT()
 #define VM_CONTINUE(op) goto* kDispatchTable[uint8_t(op)]
 #else
 #define VM_CASE(op) case op:
-#define VM_NEXT() goto dispatch
+#define VM_NEXT() continue;
+#define VM_START()
 #define VM_CONTINUE(op) \
     dispatchOp = uint8_t(op); \
     goto dispatchContinue
@@ -231,10 +233,12 @@ static void luau_execute(lua_State* L)
     base = L->base;
     k = cl->l.p->k;
 
-    VM_NEXT(); // starts the interpreter "loop"
+    VM_START(); // starts the interpreter "loop"
 
-    {
+    while (true) {
+#if VM_USE_CGOTO
     dispatch:
+#endif
         // Note: this code doesn't always execute! on some platforms we use computed goto which bypasses all of this unless we run in single-step mode
         // Therefore only ever put assertions here.
         LUAU_ASSERT(base == L->base && L->base == L->ci->base);
@@ -249,7 +253,7 @@ static void luau_execute(lua_State* L)
 
                 // allow debugstep hook to put thread into error/yield state
                 if (L->status != 0)
-                    goto exit;
+                    return;
             }
 
 #if VM_USE_CGOTO
@@ -976,7 +980,7 @@ static void luau_execute(lua_State* L)
 
                     // yield
                     if (n < 0)
-                        goto exit;
+                        return;
 
                     // ci is our callinfo, cip is our parent
                     CallInfo* ci = L->ci;
@@ -1039,7 +1043,7 @@ static void luau_execute(lua_State* L)
                 // we're done!
                 if (LUAU_UNLIKELY(ci->flags & LUA_CALLINFO_RETURN))
                 {
-                    goto exit;
+                    return;
                 }
 
                 LUAU_ASSERT(isLua(L->ci));
@@ -1053,7 +1057,7 @@ static void luau_execute(lua_State* L)
                     if (L->global->ecb.enter(L, nextproto) == 1)
                         goto reentry;
                     else
-                        goto exit;
+                        return;
                 }
 #endif
 
@@ -2371,12 +2375,17 @@ static void luau_execute(lua_State* L)
 
                             pc += LUAU_INSN_D(insn);
                             LUAU_ASSERT(unsigned(pc - cl->l.p->code) < unsigned(cl->l.p->sizecode));
-                            VM_NEXT();
+                            break;
                         }
 
                         index++;
                     }
 
+                    if (unsigned(index) < unsigned(sizearray))
+                    {
+                        VM_NEXT();
+                    }
+
                     int sizenode = 1 << h->lsizenode;
 
                     // then we advance index through the hash portion
@@ -2392,12 +2401,17 @@ static void luau_execute(lua_State* L)
 
                             pc += LUAU_INSN_D(insn);
                             LUAU_ASSERT(unsigned(pc - cl->l.p->code) < unsigned(cl->l.p->sizecode));
-                            VM_NEXT();
+                            break;
                         }
 
                         index++;
                     }
 
+                    if (unsigned(index - sizearray) < unsigned(sizenode))
+                    {
+                        VM_NEXT();
+                    }
+
                     // fallthrough to exit
                     pc++;
                     VM_NEXT();
@@ -2487,7 +2501,7 @@ static void luau_execute(lua_State* L)
                 if (L->global->ecb.enter(L, p) == 1)
                     goto reentry;
                 else
-                    goto exit;
+                    return;
 #else
                 LUAU_ASSERT(!"Opcode is only valid when VM_HAS_NATIVE is defined");
                 LUAU_UNREACHABLE();
@@ -2975,7 +2989,7 @@ static void luau_execute(lua_State* L)
 
                     // allow debugbreak hook to put thread into error/yield state
                     if (L->status != 0)
-                        goto exit;
+                        return;
                 }
 
                 VM_CONTINUE(op);
@@ -3047,8 +3061,6 @@ static void luau_execute(lua_State* L)
 #endif
         }
     }
-
-exit:;
 }
 
 void luau_execute(lua_State* L)