[llvm] [RegisterPressure] Remove dead defs correctly (PR #156576)

[Matt Arsenault via llvm-commits]

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@@ -0,0 +1,18 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 5
+; RUN: llc -mtriple=x86_64 < %s 2>&1 | FileCheck %s
+
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arsenm wrote:

Can you add a comment explaining this, and add a reference to the issue number in the file name + function name 

https://github.com/llvm/llvm-project/pull/156576