From ed9b0a91148a38b973cdb5bdd0e803d17ee36bf6 Mon Sep 17 00:00:00 2001
From: Aaron Ballman <aaron@aaronballman.com>
Date: Mon, 16 Jul 2012 16:18:18 +0000
Subject: [PATCH] MSVC's implementation of isalnum will assert on characters >
 255, so we need to use an unsigned char to ensure the integer promotion
 happens properly.  This fixes an assert in debug builds with
 CodeGen\X86\utf8.ll

llvm-svn: 160286
---
 llvm/lib/VMCore/AsmWriter.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/VMCore/AsmWriter.cpp b/llvm/lib/VMCore/AsmWriter.cpp
index 669d308b1a1c..aedb86b3eed0 100644
--- a/llvm/lib/VMCore/AsmWriter.cpp
+++ b/llvm/lib/VMCore/AsmWriter.cpp
@@ -100,7 +100,11 @@ static void PrintLLVMName(raw_ostream &OS, StringRef Name, PrefixType Prefix) {
   bool NeedsQuotes = isdigit(Name[0]);
   if (!NeedsQuotes) {
     for (unsigned i = 0, e = Name.size(); i != e; ++i) {
-      char C = Name[i];
+      // By making this unsigned, the value passed in to isalnum will always be
+      // in the range 0-255.  This is important when building with MSVC because
+      // its implementation will assert.  This situation can arise when dealing
+      // with UTF-8 multibyte characters.
+      unsigned char C = Name[i];
       if (!isalnum(C) && C != '-' && C != '.' && C != '_') {
         NeedsQuotes = true;
         break;