Add AutoUpgrade function to add new address space datalayout string to existing datalayouts.

Summary:
Add function to AutoUpgrade to change the datalayout of old X86 datalayout strings.
This adds "-p270:32:32-p271:32:32-p272:64:64" to X86 datalayouts that are otherwise valid
and don't already contain it.

This also removes the compatibility changes in https://reviews.llvm.org/D66843.
Datalayout change in https://reviews.llvm.org/D64931.

Reviewers: rnk, echristo

Subscribers: hiraditya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D67631

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@372267 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Bitcode/Reader/BitcodeReader.cpp

@@ -3648,6 +3648,11 @@ Error BitcodeReader::parseModule(uint64_t ResumeBit,
       break;
     }
     Record.clear();
+
+    // Upgrade data layout string.
+    std::string DL = llvm::UpgradeDataLayoutString(
+        TheModule->getDataLayoutStr(), TheModule->getTargetTriple());
+    TheModule->setDataLayout(DL);
   }
 }