[llvm] [AMDGPU] Add custom MachineValueType entries for buffer fat poiners (PR #127692)

[Craig Topper via llvm-commits]

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@@ -331,6 +331,10 @@ def i64x8     : ValueType<512,  231>;  // 8 Consecutive GPRs (AArch64)
 def aarch64svcount
               : ValueType<16,  232>;  // AArch64 predicate-as-counter
 def spirvbuiltin : ValueType<0, 233>; // SPIR-V's builtin type
+// AMDGPU buffer fat pointer, buffer rsrc + offset, rewritten before MIR translation
+def amdgpuBufferFatPointer : ValueType<160, 234>;
+// AMDGPU buffer strided pointer, buffer rsrc + index + offset, doesn't reach MIR
+def amdgpuBufferStridedPointer : ValueType<192, 235>;
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topperc wrote:

It really shouldn't be an invariant, but the fact that most operations default to being legal for every type can cause problems when new types are added. I know we've had issues with extending loads in the past when new types were added.

https://github.com/llvm/llvm-project/pull/127692