[llvm] [AMDGPU] Disallow negative s_load offsets in isLegalAddressingMode (PR #91327)

[Matt Arsenault via llvm-commits]

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@@ -279,38 +279,30 @@ end:
 }
 
 define amdgpu_cs void @test_sink_smem_offset_neg400(ptr addrspace(4) inreg %ptr, i32 inreg %val) {
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arsenm wrote:

Add the constant 32-bit test (6)?

https://github.com/llvm/llvm-project/pull/91327