From 94ac0343cc866c632f230d069656c4358197ddf6 Mon Sep 17 00:00:00 2001
From: Anton Korobeynikov <asl@math.spbu.ru>
Date: Tue, 14 Jul 2009 09:53:14 +0000
Subject: [PATCH] Add extra sign extension to the same bit width before int
 sign extension to another bit width. This is needed to get correct singed
 value. Patch by Artur Pietrek!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75629 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Target/MSIL/MSILWriter.cpp | 14 ++++++++++++--
 lib/Target/MSIL/MSILWriter.h   |  2 +-
 2 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/lib/Target/MSIL/MSILWriter.cpp b/lib/Target/MSIL/MSILWriter.cpp
index 61ec0283045..81e5cd4aec0 100644
--- a/lib/Target/MSIL/MSILWriter.cpp
+++ b/lib/Target/MSIL/MSILWriter.cpp
@@ -670,12 +670,18 @@ void MSILWriter::printIndirectSave(const Type* Ty) {
 
 
 void MSILWriter::printCastInstruction(unsigned int Op, const Value* V,
-                                      const Type* Ty) {
+                                      const Type* Ty, const Type* SrcTy) {
   std::string Tmp("");
   printValueLoad(V);
   switch (Op) {
   // Signed
   case Instruction::SExt:
+    // If sign extending int, convert first from unsigned to signed
+    // with the same bit size - because otherwise we will loose the sign.
+    if (SrcTy) {
+      Tmp = "conv."+getTypePostfix(SrcTy,false,true);
+      printSimpleInstruction(Tmp.c_str());
+    }
   case Instruction::SIToFP:
   case Instruction::FPToSI:
     Tmp = "conv."+getTypePostfix(Ty,false,true);
@@ -1152,9 +1158,13 @@ void MSILWriter::printInstruction(const Instruction* Inst) {
   case Instruction::Store:
     printIndirectSave(Inst->getOperand(1), Inst->getOperand(0));
     break;
+  case Instruction::SExt:
+    printCastInstruction(Inst->getOpcode(),Left,
+                         cast<CastInst>(Inst)->getDestTy(),
+                         cast<CastInst>(Inst)->getSrcTy());
+    break;
   case Instruction::Trunc:
   case Instruction::ZExt:
-  case Instruction::SExt:
   case Instruction::FPTrunc:
   case Instruction::FPExt:
   case Instruction::UIToFP:
diff --git a/lib/Target/MSIL/MSILWriter.h b/lib/Target/MSIL/MSILWriter.h
index 2ef8a85d2bc..ea0dfad0e46 100644
--- a/lib/Target/MSIL/MSILWriter.h
+++ b/lib/Target/MSIL/MSILWriter.h
@@ -187,7 +187,7 @@ namespace {
     void printIndirectSave(const Type* Ty);
 
     void printCastInstruction(unsigned int Op, const Value* V,
-                              const Type* Ty);
+                              const Type* Ty, const Type* SrcTy=0);
 
     void printGepInstruction(const Value* V, gep_type_iterator I,
                              gep_type_iterator E);