Use -no-warn

Author: jayfoad

llvm/test/MC/AMDGPU/vop3-literal.s

@@ -1,8 +1,10 @@
 // NOTE: Assertions have been autogenerated by utils/update_mc_test_checks.py UTC_ARGS: --version 5
-// RUN: not llvm-mc -triple=amdgcn -mcpu=gfx900  -mattr=+wavefrontsize64 -show-encoding %s | FileCheck %s -check-prefix=GFX9
-// RUN: not llvm-mc -triple=amdgcn -mcpu=gfx1010 -mattr=+wavefrontsize64 -show-encoding %s | FileCheck %s -check-prefix=GFX10
-// RUN: not llvm-mc -triple=amdgcn -mcpu=gfx900  -mattr=+wavefrontsize64 %s -filetype=null 2>&1 | grep -v warning: | FileCheck %s -implicit-check-not=error: -check-prefix=GFX9-ERR
-// RUN: not llvm-mc -triple=amdgcn -mcpu=gfx1010 -mattr=+wavefrontsize64 %s -filetype=null 2>&1 | grep -v warning: | FileCheck %s -implicit-check-not=error: -check-prefix=GFX10-ERR
+
+// RUN: not llvm-mc -triple=amdgcn %s -show-encoding -mcpu=gfx900 | FileCheck %s -check-prefix=GFX9
+// RUN: not llvm-mc -triple=amdgcn %s -show-encoding -mcpu=gfx1010 -mattr=+wavefrontsize64 | FileCheck %s -check-prefix=GFX10
+
+// RUN: not llvm-mc -triple=amdgcn %s -filetype=null -no-warn 2>&1 -mcpu=gfx900 | FileCheck %s -implicit-check-not=error: -check-prefix=GFX9-ERR
+// RUN: not llvm-mc -triple=amdgcn %s -filetype=null -no-warn 2>&1 -mcpu=gfx1010 -mattr=+wavefrontsize64 | FileCheck %s -implicit-check-not=error: -check-prefix=GFX10-ERR
 
 v_bfe_u32 v0, 0x3039, v1, s1
 // GFX10: v_bfe_u32 v0, 0x3039, v1, s1            ; encoding: [0x00,0x00,0x48,0xd5,0xff,0x02,0x06,0x00,0x39,0x30,0x00,0x00]