Do not emit shadow copied for inout parameters

include/swift/SILOptimizer/PassManager/Passes.def

@@ -133,8 +133,6 @@ PASS(HighLevelLICM, "high-level-licm",
      "High Level Loop invariant code motion")
 PASS(IVInfoPrinter, "iv-info-printer",
      "Display induction variable information")
-PASS(InOutDeshadowing, "inout-deshadow",
-     "Remove inout argument shadow variables")
 PASS(InstCount, "inst-count",
      "Count all instructions in the module using llvm Statistics")
 PASS(JumpThreadSimplifyCFG, "simplify-cfg",

lib/SIL/TypeLowering.cpp

@@ -121,6 +121,10 @@ CaptureKind TypeConverter::getDeclCaptureKind(CapturedValue capture) {
       if (var->isLet() && !getTypeLowering(var->getType()).isAddressOnly())
         return CaptureKind::Constant;
 
+      if (var->getType()->is<InOutType>()) {
+        return CaptureKind::StorageAddress;
+      }
+
       // If we're capturing into a non-escaping closure, we can generally just
       // capture the address of the value as no-escape.
       return capture.isNoEscape() ?

lib/SILGen/SILGenProlog.cpp

@@ -262,30 +262,18 @@ struct ArgumentInitHelper {
         gen.B.createDebugValueAddr(loc, address, {vd->isLet(), ArgNo});
         return;
       }
-
-      // Allocate the local variable for the inout.
-      auto initVar = gen.emitLocalVariableWithCleanup(vd, false, ArgNo);
-
-      // Initialize with the value from the inout with an "autogenerated"
-      // copyaddr.
-      loc.markAutoGenerated();
-      gen.B.createCopyAddr(loc, address, initVar->getAddress(),
-                           IsNotTake, IsInitialization);
-      initVar->finishInitialization(gen);
-
-      // Set up a cleanup to write back to the inout.
-      gen.Cleanups.pushCleanup<CleanupWriteBackToInOut>(vd, address);
+      assert(argrv.getType().isAddress() && "expected inout to be address");
     } else {
       assert(vd->isLet() && "expected parameter to be immutable!");
       // If the variable is immutable, we can bind the value as is.
       // Leave the cleanup on the argument, if any, in place to consume the
       // argument if we're responsible for it.
-      gen.VarLocs[vd] = SILGenFunction::VarLoc::get(argrv.getValue());
-      if (argrv.getType().isAddress())
-        gen.B.createDebugValueAddr(loc, argrv.getValue(), {vd->isLet(), ArgNo});
-      else
-        gen.B.createDebugValue(loc, argrv.getValue(), {vd->isLet(), ArgNo});
     }
+    gen.VarLocs[vd] = SILGenFunction::VarLoc::get(argrv.getValue());
+    if (argrv.getType().isAddress())
+      gen.B.createDebugValueAddr(loc, argrv.getValue(), {vd->isLet(), ArgNo});
+    else
+      gen.B.createDebugValue(loc, argrv.getValue(), {vd->isLet(), ArgNo});
   }
 
   void emitParam(ParamDecl *PD) {

lib/SILOptimizer/Mandatory/CMakeLists.txt

@@ -6,5 +6,4 @@ set(MANDATORY_SOURCES
   Mandatory/DiagnoseUnreachable.cpp
   Mandatory/PredictableMemOpt.cpp
   Mandatory/ConstantPropagation.cpp
-  Mandatory/InOutDeshadowing.cpp
   PARENT_SCOPE)

lib/SILOptimizer/PassManager/Passes.cpp

@@ -89,7 +89,6 @@ bool swift::runSILDiagnosticPasses(SILModule &Module) {
   // Otherwise run the rest of diagnostics.
   PM.addCapturePromotion();
   PM.addAllocBoxToStack();
-  PM.addInOutDeshadowing();
   PM.addNoReturnFolding();
   PM.addDefiniteInitialization();