Basic fix for PR#591; don't convert an fprintf() to an fwrite() if there

is a mismatch in their character type pointers (i.e. fprintf() prints an
array of ubytes while fwrite() takes an array of sbytes).
We can probably do better than this (such as casting the ubyte to an
sbyte).

llvm-svn: 22310

llvm/lib/Transforms/IPO/SimplifyLibCalls.cpp

@@ -1305,6 +1305,15 @@ public:
       Function* fwrite_func = SLC.get_fwrite(FILEptr_type);
       if (!fwrite_func)
         return false;
+
+      // Make sure that the fprintf() and fwrite() functions both take the
+      // same type of char pointer.
+      if (ci->getOperand(2)->getType() !=
+          fwrite_func->getFunctionType()->getParamType(0))
+      {
+        return false;
+      }
+
       std::vector<Value*> args;
       args.push_back(ci->getOperand(2));
       args.push_back(ConstantUInt::get(SLC.getIntPtrType(),len));