[llvm] X86: Use LiveRegUnits in findDeadCallerSavedReg (PR #156817)

[Phoebe Wang via llvm-commits]

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@@ -6,5 +6,5 @@ define cc 92 < 9 x i64 > @clobber() {
   ret < 9 x i64 > undef
   ; CHECK-LABEL: clobber:
   ; CHECK-NOT: popq %rsp
-  ; CHECK: addq $8, %rsp
+  ; CHECK: pushq %rax
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phoebewang wrote:

popq?

https://github.com/llvm/llvm-project/pull/156817