[llvm] [X86] Add MI-layer routine for getting the index of the first address operand (PR #78019)

[Phoebe Wang via llvm-commits]

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@@ -1,4 +1,5 @@
-; RUN: llc -verify-machineinstrs -mcpu=corei7-avx %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=NO-FLAGS
+; RUN: llc -verify-machineinstrs -mcpu=corei7-avx -disable-x86-lea-opt %s -o - | FileCheck %s --check-prefix=CHECK --check-prefix=NO-FLAGS
+; Disable the x86-optimize-LEAs pass, since it may introduce an intermediate LEA instruction that changes the base register of the vmovaps instructions from %rsp to something else.
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phoebewang wrote:

Why do we need the change here? I understand the patch is NFC.

https://github.com/llvm/llvm-project/pull/78019