Fix 177.mesa compilation, don't use floating point regs for base addresses!

llvm-svn: 15720
diff --git a/llvm/lib/Target/PowerPC/PPC32ISelSimple.cpp b/llvm/lib/Target/PowerPC/PPC32ISelSimple.cpp
index f175159..eabe9d8 100644
--- a/llvm/lib/Target/PowerPC/PPC32ISelSimple.cpp
+++ b/llvm/lib/Target/PowerPC/PPC32ISelSimple.cpp
@@ -1535,7 +1535,7 @@
             .addReg(PPC::R1);
             if (GPR_remaining > 0) {
               BuildMI(BB, PPC::LWZ, 2, GPR[GPR_idx])
-              .addSImm(ArgOffset).addReg(ArgReg);
+              .addSImm(ArgOffset).addReg(PPC::R1);
               CallMI->addRegOperand(GPR[GPR_idx], MachineOperand::Use);
             }
           }