[AMDGPU] - Add address space for strided buffers (#74471)

This is an experimental address space for strided buffers. These buffers
can have structs as elements and
a stride > 1.
These pointers allow the indexed access in units of stride, i.e., they
point at `buffer[index * stride]`.
Thus, we can use the `idxen` modifier for buffer loads.

We assign address space 9 to 192-bit buffer pointers which contain a
128-bit descriptor, a 32-bit offset and a 32-bit index. Essentially,
they are fat buffer pointers with an additional 32-bit index.
diff --git a/llvm/test/CodeGen/AMDGPU/amdgpu-simplify-libcall-fmin-splat.ll b/llvm/test/CodeGen/AMDGPU/amdgpu-simplify-libcall-fmin-splat.ll
index e546766..36f65c1 100644
--- a/llvm/test/CodeGen/AMDGPU/amdgpu-simplify-libcall-fmin-splat.ll
+++ b/llvm/test/CodeGen/AMDGPU/amdgpu-simplify-libcall-fmin-splat.ll
@@ -1,7 +1,7 @@
 ; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 2
 ; RUN: opt -S -mtriple=amdgcn-amd-amdhsa -passes=amdgpu-simplifylib %s | FileCheck %s
 
-target datalayout = "e-p:64:64-p1:64:64-p2:32:32-p3:32:32-p4:64:64-p5:32:32-p6:32:32-p7:160:256:256:32-p8:128:128-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64-S32-A5-G1-ni:7:8"
+target datalayout = "e-p:64:64-p1:64:64-p2:32:32-p3:32:32-p4:64:64-p5:32:32-p6:32:32-p7:160:256:256:32-p8:128:128-i64:64-v16:16-v24:32-v32:32-v48:64-v96:128-v192:256-v256:256-v512:512-v1024:1024-v2048:2048-n32:64-S32-A5-G1-ni:7:8:9"
 
 declare <2 x float> @_Z4fminDv2_ff(<2 x float>, float)
 declare <2 x float> @_Z4fminDv2_fS_(<2 x float>, <2 x float>)