fix ptxas

Author: AlexMaclean

llvm/test/CodeGen/NVPTX/atomics-b128.ll

@@ -2,7 +2,7 @@
 ; RUN: not llc < %s -mcpu=sm_90 -mattr=+ptx82 2>&1 | FileCheck %s --check-prefix=ERROR
 ; RUN: not llc < %s -mcpu=sm_80 -mattr=+ptx84 2>&1 | FileCheck %s --check-prefix=ERROR
 ; RUN: llc < %s -mcpu=sm_90 -mattr=+ptx84 | FileCheck %s --check-prefix=CHECK
-; RUN: %if ptxas %{ llc < %s -march=nvptx64 -mcpu=sm_90 -mattr=+ptx84 | %ptxas-verify -arch=sm_90 %}
+; RUN: %if ptxas-sm_90 && ptxas-isa-8.4 %{ llc < %s -mcpu=sm_90 -mattr=+ptx84 | %ptxas-verify -arch=sm_90 %}
 
 ;; TODO: Update cmpxchg.py so that it can automatically generate the IR for
 ;;       these test cases.