SIL: Fix liveness check for the thrown error result

Author: slavapestov

include/swift/SIL/SILArgument.h

@@ -433,6 +433,8 @@ class SILFunctionArgument : public SILArgument {
 
   bool isIndirectResult() const;
 
+  bool isIndirectErrorResult() const;
+
   SILArgumentConvention getArgumentConvention() const;
 
   /// Given that this is an entry block argument, and given that it does

lib/SIL/IR/SILArgument.cpp

@@ -64,6 +64,14 @@ bool SILFunctionArgument::isIndirectResult() const {
   return getIndex() < numIndirectResults;
 }
 
+bool SILFunctionArgument::isIndirectErrorResult() const {
+  auto numIndirectResults =
+      getFunction()->getConventions().getNumIndirectSILResults();
+  auto numIndirectErrorResults =
+      getFunction()->getConventions().getNumIndirectSILErrorResults();
+  return getIndex() < numIndirectResults + numIndirectErrorResults;
+}
+
 SILArgumentConvention SILFunctionArgument::getArgumentConvention() const {
   return getFunction()->getConventions().getSILArgumentConvention(getIndex());
 }

lib/SIL/Verifier/MemoryLifetimeVerifier.cpp

@@ -563,7 +563,12 @@ void MemoryLifetimeVerifier::checkFunction(BitDataflow &dataFlow) {
       locations.setBits(expectedThrowBits, funcArg);
       break;
     case SILArgumentConvention::Indirect_Out:
-      locations.setBits(expectedReturnBits, funcArg);
+      if (funcArg->isIndirectErrorResult()) {
+        locations.setBits(expectedThrowBits, funcArg);
+      } else {
+        assert(funcArg->isIndirectResult());
+        locations.setBits(expectedReturnBits, funcArg);
+      }
       break;
     default:
       break;