Merge 83417 from mainline.

r83391 was completely broken since Twines keep references to their inputs, and
some of the inputs were temporaries.  Here's a real fix for the miscompilation.
Thanks to sabre for pointing out the problem.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_26@83859 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/Triple.cpp

@@ -9,6 +9,7 @@
 
 #include "llvm/ADT/Triple.h"
 
+#include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/Twine.h"
 #include <cassert>
 #include <cstring>
@@ -326,10 +327,14 @@ void Triple::setOS(OSType Kind) {
 }
 
 void Triple::setArchName(const StringRef &Str) {
-  // Work around a miscompilation bug in gcc 4.0.3.
-  Twine a = getVendorName() + "-" + getOSAndEnvironmentName();
-  Twine b = Str + "-" + a;
-  setTriple(b);
+  // Work around a miscompilation bug for Twines in gcc 4.0.3.
+  SmallString<64> Triple;
+  Triple += Str;
+  Triple += "-";
+  Triple += getVendorName();
+  Triple += "-";
+  Triple += getOSAndEnvironmentName();
+  setTriple(Triple.str());
 }
 
 void Triple::setVendorName(const StringRef &Str) {