[llvm] x86: fix musttail sibcall miscompilation (PR #168956)

[Folkert de Vries via llvm-commits]

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@@ -0,0 +1,197 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
+; RUN: llc < %s -mtriple=x86_64-unknown-unknown -x86-asm-syntax=intel | FileCheck %s
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folkertdev wrote:

is testing just for x86_64 OK here?

https://github.com/llvm/llvm-project/pull/168956