[llvm] [SPIR-V] Deduce pointee type for all global variables, not only initialized ones (PR #202047)

[Dmitry Sidorov via llvm-commits]

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@@ -0,0 +1,37 @@
+; A global variable's pointee type is concrete (its value type) and must be used
+; even for an undef-initialized, NON-constant aggregate — e.g. a Workgroup
+; `[N x T]` shared tile. Otherwise the variable's type is inferred from a flat
+; element-typed GEP use as the scalar element, the array-to-pointer-decay rewrite
+; is skipped, and under Logical SPIR-V the dynamic index is dropped (every
+; invocation accesses element 0). The variable must keep its array type and be
+; indexed with an OpAccessChain carrying the dynamic index.
+
+; RUN: llc -verify-machineinstrs -O0 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - -filetype=obj | spirv-val %}
+
+ at tile = internal addrspace(3) global [64 x i32] undef, align 16
+
+; CHECK-DAG: %[[#U32:]] = OpTypeInt 32 0
+; CHECK-DAG: %[[#Arr:]] = OpTypeArray %[[#U32]] %[[#]]
+; CHECK-DAG: %[[#ArrPtr:]] = OpTypePointer Workgroup %[[#Arr]]
+; CHECK-DAG: %[[#EltPtr:]] = OpTypePointer Workgroup %[[#U32]]
+; CHECK-DAG: %[[#Tile:]] = OpVariable %[[#ArrPtr]] Workgroup
+
+; The (dynamic) index survives as an OpAccessChain into the array tile; it is not
+; dropped, and the variable is not collapsed to a scalar `OpTypePointer Workgroup
+; %u32` with no index.
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MrSidims wrote:

Unnecessary description.

https://github.com/llvm/llvm-project/pull/202047