Revert r237385, "[CodeGen] Reuse stack space from unused function results"

It broke clang stage2, at least tblgen.

llvm-svn: 237418

1 files changed, 3 insertions, 20 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 26d9e1896d4..2922a215ade 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -3077,18 +3077,10 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   // If the call returns a temporary with struct return, create a temporary
   // alloca to hold the result, unless one is given to us.
   llvm::Value *SRetPtr = nullptr;
-  size_t UnusedReturnSize = 0;
   if (RetAI.isIndirect() || RetAI.isInAlloca()) {
     SRetPtr = ReturnValue.getValue();
-    if (!SRetPtr) {
+    if (!SRetPtr)
       SRetPtr = CreateMemTemp(RetTy);
-      if (HaveInsertPoint()) {
-        uint64_t size =
-            CGM.getDataLayout().getTypeAllocSize(ConvertTypeForMem(RetTy));
-        if (EmitLifetimeStart(size, SRetPtr))
-          UnusedReturnSize = size;
-      }
-    }
     if (IRFunctionArgs.hasSRetArg()) {
       IRCallArgs[IRFunctionArgs.getSRetArgNo()] = SRetPtr;
     } else {
@@ -3420,10 +3412,6 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   // insertion point; this allows the rest of IRgen to discard
   // unreachable code.
   if (CS.doesNotReturn()) {
-    if (UnusedReturnSize)
-      EmitLifetimeEnd(llvm::ConstantInt::get(Int64Ty, UnusedReturnSize),
-                      SRetPtr);
-
     Builder.CreateUnreachable();
     Builder.ClearInsertionPoint();
 
@@ -3452,13 +3440,8 @@ RValue CodeGenFunction::EmitCall(const CGFunctionInfo &CallInfo,
   RValue Ret = [&] {
     switch (RetAI.getKind()) {
     case ABIArgInfo::InAlloca:
-    case ABIArgInfo::Indirect: {
-      RValue ret = convertTempToRValue(SRetPtr, RetTy, SourceLocation());
-      if (UnusedReturnSize)
-        EmitLifetimeEnd(llvm::ConstantInt::get(Int64Ty, UnusedReturnSize),
-                        SRetPtr);
-      return ret;
-    }
+    case ABIArgInfo::Indirect:
+      return convertTempToRValue(SRetPtr, RetTy, SourceLocation());
 
     case ABIArgInfo::Ignore:
       // If we are ignoring an argument that had a result, make sure to