sil-opt: Add flag to disable aggressive reg2mem mode

Author: kateinoigakukun

lib/DriverTool/sil_opt_main.cpp

@@ -593,6 +593,11 @@ struct SILOptOptions {
       "enable-address-dependencies",
       llvm::cl::desc("Enable enforcement of lifetime dependencies on addressable values."));
 
+  llvm::cl::opt<bool> DisaleAggressiveReg2Mem = llvm::cl::opt<bool>(
+      "disable-aggressive-reg2mem",
+      llvm::cl::desc("Disable aggressive reg2mem optimizations."),
+      llvm::cl::init(false));
+
   llvm::cl::opt<bool> EnableCalleeAllocatedCoroAbi = llvm::cl::opt<bool>(
       "enable-callee-allocated-coro-abi",
       llvm::cl::desc("Override per-platform settings and use yield_once_2."),
@@ -921,6 +926,8 @@ int sil_opt_main(ArrayRef<const char *> argv, void *MainAddr) {
       options.EnablePackMetadataStackPromotion;
 
   SILOpts.EnableAddressDependencies = options.EnableAddressDependencies;
+  if (options.DisaleAggressiveReg2Mem)
+    SILOpts.UseAggressiveReg2MemForCodeSize = false;
   if (options.EnableCalleeAllocatedCoroAbi)
     SILOpts.CoroutineAccessorsUseYieldOnce2 = true;
   if (options.DisableCalleeAllocatedCoroAbi)