[llvm] [X86][BreakFalseDeps] Using reverse order for undef register selection (PR #137569)

[Simon Pilgrim via llvm-commits]

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@@ -3,19 +3,6 @@
 ; RUN: llc < %s -mtriple=x86_64-unknown -mattr=+avx | FileCheck %s
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RKSimon wrote:

Update checks and regenerate:
```
; RUN: llc < %s -mtriple=i686-unknown -mattr=+avx | FileCheck %s --check-prefix=X86
; RUN: llc < %s -mtriple=x86_64-unknown -mattr=+avx | FileCheck %s --check-prefix=X64
```

https://github.com/llvm/llvm-project/pull/137569