commit 6aab1117e859b6cb0cc9a4753481a8ef563cf871
author Leny Kholodov <lkholodov@accesssoftek.com> Mon Jun 08 10:23:49 2015 +0000
committer Leny Kholodov <lkholodov@accesssoftek.com> Mon Jun 08 10:23:49 2015 +0000
tree 3af9f3f6da73d56642fae02f356545bd862964ce
parent c789e1d57bb9e4513dc212d1558e4c49bc88f8f5

[CodeGen] Reuse stack space from unused function results (with more accurate unused result detection)

This patch fixes issues with unused result detection which were found in patch http://reviews.llvm.org/D9743.

Differential Revision: http://reviews.llvm.org/D10042

llvm-svn: 239294

clang/lib/CodeGen/CGExprAgg.cpp

diff --git a/clang/lib/CodeGen/CGExprAgg.cpp b/clang/lib/CodeGen/CGExprAgg.cpp
index 6fedf0e..8b1bc69 100644
--- a/clang/lib/CodeGen/CGExprAgg.cpp
+++ b/clang/lib/CodeGen/CGExprAgg.cpp
@@ -34,6 +34,7 @@
   CodeGenFunction &CGF;
   CGBuilderTy &Builder;
   AggValueSlot Dest;
+  bool IsResultUnused;
 
   /// We want to use 'dest' as the return slot except under two
   /// conditions:
@@ -48,7 +49,7 @@
     if (!shouldUseDestForReturnSlot())
       return ReturnValueSlot();
 
-    return ReturnValueSlot(Dest.getAddr(), Dest.isVolatile());
+    return ReturnValueSlot(Dest.getAddr(), Dest.isVolatile(), IsResultUnused);
   }
 
   AggValueSlot EnsureSlot(QualType T) {
@@ -61,9 +62,9 @@
   }
 
 public:
-  AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest)
-    : CGF(cgf), Builder(CGF.Builder), Dest(Dest) {
-  }
+  AggExprEmitter(CodeGenFunction &cgf, AggValueSlot Dest, bool IsResultUnused)
+    : CGF(cgf), Builder(CGF.Builder), Dest(Dest),
+    IsResultUnused(IsResultUnused) { }
 
   //===--------------------------------------------------------------------===//
   //                               Utilities
@@ -1394,7 +1395,7 @@
   // Optimize the slot if possible.
   CheckAggExprForMemSetUse(Slot, E, *this);
  
-  AggExprEmitter(*this, Slot).Visit(const_cast<Expr*>(E));
+  AggExprEmitter(*this, Slot, Slot.isIgnored()).Visit(const_cast<Expr*>(E));
 }
 
 LValue CodeGenFunction::EmitAggExprToLValue(const Expr *E) {