[llvm] [NFC][PowerPC] Add test to check lanemasks for subregisters. (PR #94363)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,67 @@
+# RUN: llc -mcpu=pwr10 -O3 -ppc-track-subreg-liveness -verify-machineinstrs \
+# RUN:   -mtriple=powerpc64le-unknown-linux-gnu -run-pass=greedy,virtregrewriter \
+# RUN:   -debug-only=regalloc -o - %s 2>&1 >/dev/null | FileCheck %s
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arsenm wrote:

Use -filetype=null instead of outputting to /dev/null. Also don't need -O3 or -verify-machineinstrs. 

Also needs REQUIRES: asserts if you're checking the debug output 

https://github.com/llvm/llvm-project/pull/94363