[llvm] [AMDGPU] Don't realign already allocated LDS. Point fix for 106412 (PR #106421)

[Jon Chesterfield via llvm-commits]

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@@ -0,0 +1,15 @@
+; RUN: opt -S -mtriple=amdgcn-- -amdgpu-lower-module-lds < %s | FileCheck %s
+
+; Can't have a second variable without absolute_symbol showing it is realigned as
+; there is a fatal error on mixing absolute and non-absolute symbols
+
+; CHECK: @lds.dont_realign = internal addrspace(3) global i64 undef, align 2, !absolute_symbol !0
+ at lds.dont_realign = internal addrspace(3) global i64 undef, align 2, !absolute_symbol !0
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JonChesterfield wrote:

It doesn't do much harm here but in general duplicating test cases for zero changes in code path seems bad

I'd lean towards the default for tests should probably correspond to whatever clang marks them with, which seems to be poison now but I'm sure used to be undef

https://github.com/llvm/llvm-project/pull/106421