From: Jakob Stoklund Olesen <stoklund@2pi.dk>
Date: Mon, 13 Sep 2010 21:29:45 +0000 (+0000)
Subject: Let's just declare that it is impossible to construct a std::pair from a null
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b3e9681cc0ea2d52a1f8cd09880656780dce4073;p=oota-llvm.git

Let's just declare that it is impossible to construct a std::pair from a null
pointer and work around that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@113788 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/CodeGen/SplitKit.cpp b/lib/CodeGen/SplitKit.cpp
index 29474f0d551..5de7688c68d 100644
--- a/lib/CodeGen/SplitKit.cpp
+++ b/lib/CodeGen/SplitKit.cpp
@@ -339,6 +339,13 @@ bool SplitAnalysis::getMultiUseBlocks(BlockPtrSet &Blocks) {
 //                               LiveIntervalMap
 //===----------------------------------------------------------------------===//
 
+// Work around the fact that the std::pair constructors are broken for pointer
+// pairs in some implementations. makeVV(x, 0) works.
+static inline std::pair<const VNInfo*, VNInfo*>
+makeVV(const VNInfo *a, VNInfo *b) {
+  return std::make_pair(a, b);
+}
+
 // defValue - Introduce a li_ def for ParentVNI that could be later than
 // ParentVNI->def.
 VNInfo *LiveIntervalMap::defValue(const VNInfo *ParentVNI, SlotIndex Idx) {
@@ -351,19 +358,9 @@ VNInfo *LiveIntervalMap::defValue(const VNInfo *ParentVNI, SlotIndex Idx) {
     return mapValue(ParentVNI, Idx);
 
   // This is a complex def. Mark with a NULL in valueMap.
-  VNInfo *OldVNI =
-    valueMap_.insert(
-      ValueMap::value_type(ParentVNI, static_cast<VNInfo *>(0))).first->second;
-      // The static_cast<VNInfo *> is only needed to work around a bug in an
-      // old version of the C++0x standard which the following compilers
-      // implemented and have yet to fix:
-      //
-      // Microsoft Visual Studio 2010 Version 10.0.30319.1 RTMRel
-      // Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.30319.01
-      //
-      // If/When we move to C++0x, this can be replaced by nullptr.
-  (void)OldVNI;
-  assert(OldVNI == 0 && "Simple/Complex values mixed");
+  VNInfo *&OldVNI = valueMap_[ParentVNI];
+  assert(!OldVNI && "Simple/Complex values mixed");
+  OldVNI = 0;
 
   // Should we insert a minimal snippet of VNI LiveRange, or can we count on
   // callers to do that? We need it for lookups of complex values.
@@ -380,15 +377,7 @@ VNInfo *LiveIntervalMap::mapValue(const VNInfo *ParentVNI, SlotIndex Idx) {
 
   // Use insert for lookup, so we can add missing values with a second lookup.
   std::pair<ValueMap::iterator,bool> InsP =
-    valueMap_.insert(ValueMap::value_type(ParentVNI, static_cast<VNInfo *>(0)));
-    // The static_cast<VNInfo *> is only needed to work around a bug in an
-    // old version of the C++0x standard which the following compilers
-    // implemented and have yet to fix:
-    //
-    // Microsoft Visual Studio 2010 Version 10.0.30319.1 RTMRel
-    // Microsoft (R) 32-bit C/C++ Optimizing Compiler Version 16.00.30319.01
-    //
-    // If/When we move to C++0x, this can be replaced by nullptr.
+    valueMap_.insert(makeVV(ParentVNI, 0));
 
   // This was an unknown value. Create a simple mapping.
   if (InsP.second)