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[SPIR-V] Add InferAddrspace pass to the backend
This commit enables a pass in the backend which propagates the addrspace of the pointers down to the last use, making sure the addrspace remains consistent, and thus stripping any addrspacecast. This is required to lower LLVM-IR to logical SPIR-V, which does not support generic pointers. This is now required as HLSL emits several address spaces, and thus addrspacecasts in some cases: Example 1: resource access ```llvm %handle = tail call target("spirv.VulkanBuffer", ...) %rptr = @llvm.spv.resource.getpointer(%handle, ...); %cptr = addrspacecast ptr addrspace(11) %rptr to ptr %fptr = load i32, ptr %cptr ``` Example 2: object methods ```llvm define void @objectmethod(ptr %this) { } define void @foo(ptr addrspace(11) %object) { call void @objectmethod(ptr addrspacecast(addrspace(11) %object to ptr)); } ```
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‎llvm/lib/Target/SPIRV/SPIRVTargetMachine.cpp

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@@ -32,6 +32,7 @@
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#include "llvm/Passes/PassBuilder.h"
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#include "llvm/Target/TargetOptions.h"
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#include "llvm/Transforms/Scalar/Reg2Mem.h"
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#include "llvm/Transforms/Scalar.h"
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#include "llvm/Transforms/Utils.h"
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#include <optional>
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@@ -190,6 +191,14 @@ void SPIRVPassConfig::addIRPasses() {
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TargetPassConfig::addIRPasses();
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if (TM.getSubtargetImpl()->isVulkanEnv()) {
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// The frontend has a tendency to quickly addrspacecast pointers to the
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// default address space, and relies on addrspacecast instructions at the
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// boundaries. Vulkan does not allow such things, and we must keep the
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// pointer address space stable.
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// This pass will determine real address space of a pointer, and patch
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// instructions removing Addrspacecasts.
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addPass(createInferAddressSpacesPass(/* AddressSpace= */ 0));
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// 1. Simplify loop for subsequent transformations. After this steps, loops
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// have the following properties:
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// - loops have a single entry edge (pre-header to loop header).

‎llvm/test/CodeGen/SPIRV/pointers/pointer-addrspacecast.ll

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; RUN: llc -verify-machineinstrs -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - | FileCheck %s
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; RUN: %if spirv-tools %{ llc -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - -filetype=obj | spirv-val %}
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; CHECK-DAG: %[[#uint:]] = OpTypeInt 32 0
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; CHECK-DAG: %[[#uint_0:]] = OpConstant %[[#uint]] 0
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; CHECK-DAG: %[[#ptr_uint:]] = OpTypePointer Private %[[#uint]]
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; CHECK-DAG: %[[#var:]] = OpVariable %[[#ptr_uint]] Private %[[#uint_0]]
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; CHECK-DAG: OpName %[[#func_simple:]] "simple"
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; CHECK-DAG: OpName %[[#func_chain:]] "chain"
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@global = internal addrspace(10) global i32 zeroinitializer
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define void @simple() {
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; CHECK: %[[#func_simple]] = OpFunction
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entry:
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%ptr = getelementptr i32, ptr addrspace(10) @global, i32 0
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%casted = addrspacecast ptr addrspace(10) %ptr to ptr
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%val = load i32, ptr %casted
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; CHECK: %{{.*}} = OpLoad %[[#uint]] %[[#var]] Aligned 4
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ret void
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}
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define void @chain() {
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; CHECK: %[[#func_chain]] = OpFunction
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entry:
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%a = getelementptr i32, ptr addrspace(10) @global, i32 0
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%b = addrspacecast ptr addrspace(10) %a to ptr
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%c = getelementptr i32, ptr %b, i32 0
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%d = addrspacecast ptr %c to ptr addrspace(10)
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%e = addrspacecast ptr addrspace(10) %d to ptr
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%val = load i32, ptr %e
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; CHECK: %{{.*}} = OpLoad %[[#uint]] %[[#var]] Aligned 4
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ret void
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}

‎llvm/test/CodeGen/SPIRV/pointers/resource-addrspacecast-2.ll

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; RUN: llc -verify-machineinstrs -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - | FileCheck %s --match-full-lines
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; RUN: %if spirv-tools %{ llc -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - -filetype=obj | spirv-val %}
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; FIXME(134119): enable-this once Offset decoration are added.
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; XFAIL: spirv-tools
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%S2 = type { { [10 x { i32, i32 } ] }, i32 }
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; CHECK-DAG: %[[#uint:]] = OpTypeInt 32 0
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; CHECK-DAG: %[[#uint_0:]] = OpConstant %[[#uint]] 0
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; CHECK-DAG: %[[#uint_1:]] = OpConstant %[[#uint]] 1
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; CHECK-DAG: %[[#uint_3:]] = OpConstant %[[#uint]] 3
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; CHECK-DAG: %[[#uint_10:]] = OpConstant %[[#uint]] 10
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; CHECK-DAG: %[[#uint_11:]] = OpConstant %[[#uint]] 11
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; CHECK-DAG: %[[#ptr_StorageBuffer_uint:]] = OpTypePointer StorageBuffer %[[#uint]]
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; CHECK-DAG: %[[#t_s2_s_a_s:]] = OpTypeStruct %[[#uint]] %[[#uint]]
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; CHECK-DAG: %[[#t_s2_s_a:]] = OpTypeArray %[[#t_s2_s_a_s]] %[[#uint_10]]
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; CHECK-DAG: %[[#t_s2_s:]] = OpTypeStruct %[[#t_s2_s_a]]
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; CHECK-DAG: %[[#t_s2:]] = OpTypeStruct %[[#t_s2_s]] %[[#uint]]
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; CHECK-DAG: %[[#ptr_StorageBuffer_struct:]] = OpTypePointer StorageBuffer %[[#t_s2]]
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; CHECK-DAG: %[[#rarr:]] = OpTypeRuntimeArray %[[#t_s2]]
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; CHECK-DAG: %[[#rarr_struct:]] = OpTypeStruct %[[#rarr]]
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; CHECK-DAG: %[[#spirv_VulkanBuffer:]] = OpTypePointer StorageBuffer %[[#rarr_struct]]
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declare target("spirv.VulkanBuffer", [0 x %S2], 12, 1) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0s_Ss_12_1t(i32, i32, i32, i32, i1)
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define void @main() "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" {
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entry:
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%handle = tail call target("spirv.VulkanBuffer", [0 x %S2], 12, 1) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0s_Ss_12_1t(i32 0, i32 0, i32 1, i32 0, i1 false)
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; CHECK: %[[#resource:]] = OpVariable %[[#spirv_VulkanBuffer]] StorageBuffer
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%ptr = tail call noundef align 4 dereferenceable(4) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0s_Ss_12_1t(target("spirv.VulkanBuffer", [0 x %S2], 12, 1) %handle, i32 0)
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; CHECK: %[[#a:]] = OpCopyObject %[[#spirv_VulkanBuffer]] %[[#resource]]
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; CHECK: %[[#b:]] = OpAccessChain %[[#ptr_StorageBuffer_struct]] %[[#a:]] %[[#uint_0]] %[[#uint_0]]
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%casted = addrspacecast ptr addrspace(11) %ptr to ptr
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; CHECK: %[[#ptr2:]] = OpInBoundsAccessChain %[[#ptr_StorageBuffer_uint]] %[[#b:]] %[[#uint_0]] %[[#uint_0]] %[[#uint_3]] %[[#uint_1]]
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%ptr2 = getelementptr inbounds %S2, ptr %casted, i64 0, i32 0, i32 0, i32 3, i32 1
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; CHECK: OpStore %[[#ptr2]] %[[#uint_10]] Aligned 4
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store i32 10, ptr %ptr2, align 4
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; Another store, but this time using LLVM's ability to load the first element
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; without an explicit GEP. The backend has to determine the ptr type and
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; generate the appropriate access chain.
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; CHECK: %[[#ptr3:]] = OpInBoundsAccessChain %[[#ptr_StorageBuffer_uint]] %[[#b:]] %[[#uint_0]] %[[#uint_0]] %[[#uint_0]] %[[#uint_0]]
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; CHECK: OpStore %[[#ptr3]] %[[#uint_11]] Aligned 4
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store i32 11, ptr %casted, align 4
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ret void
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}
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declare ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0s_S2s_12_1t(target("spirv.VulkanBuffer", [0 x %S2], 12, 1), i32)

‎llvm/test/CodeGen/SPIRV/pointers/resource-addrspacecast.ll

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; RUN: llc -verify-machineinstrs -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - | FileCheck %s
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; RUN: %if spirv-tools %{ llc -O3 -mtriple=spirv-unknown-vulkan1.3-compute %s -o - -filetype=obj | spirv-val %}
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; FIXME(134119): enable-this once Offset decoration are added.
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; XFAIL: spirv-tools
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%struct.S = type { i32 }
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; CHECK-DAG: %[[#uint:]] = OpTypeInt 32 0
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; CHECK-DAG: %[[#uint_0:]] = OpConstant %[[#uint]] 0
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; CHECK-DAG: %[[#uint_10:]] = OpConstant %[[#uint]] 10
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; CHECK-DAG: %[[#ptr_StorageBuffer_uint:]] = OpTypePointer StorageBuffer %[[#uint]]
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; CHECK-DAG: %[[#struct:]] = OpTypeStruct %[[#uint]]
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; CHECK-DAG: %[[#ptr_StorageBuffer_struct:]] = OpTypePointer StorageBuffer %[[#struct]]
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; CHECK-DAG: %[[#rarr:]] = OpTypeRuntimeArray %[[#struct]]
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; CHECK-DAG: %[[#rarr_struct:]] = OpTypeStruct %[[#rarr]]
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; CHECK-DAG: %[[#spirv_VulkanBuffer:]] = OpTypePointer StorageBuffer %[[#rarr_struct]]
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declare target("spirv.VulkanBuffer", [0 x %struct.S], 12, 1) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0s_struct.Ss_12_1t(i32, i32, i32, i32, i1)
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define void @main() "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" {
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entry:
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%handle = tail call target("spirv.VulkanBuffer", [0 x %struct.S], 12, 1) @llvm.spv.resource.handlefrombinding.tspirv.VulkanBuffer_a0s_struct.Ss_12_1t(i32 0, i32 0, i32 1, i32 0, i1 false)
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; CHECK: %[[#resource:]] = OpVariable %[[#spirv_VulkanBuffer]] StorageBuffer
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%ptr = tail call noundef align 4 dereferenceable(4) ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0s_struct.Ss_12_1t(target("spirv.VulkanBuffer", [0 x %struct.S], 12, 1) %handle, i32 0)
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; CHECK: %[[#a:]] = OpCopyObject %[[#spirv_VulkanBuffer]] %[[#resource]]
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; CHECK: %[[#b:]] = OpAccessChain %[[#ptr_StorageBuffer_struct]] %[[#a:]] %[[#uint_0]] %[[#uint_0]]
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; CHECK: %[[#c:]] = OpInBoundsAccessChain %[[#ptr_StorageBuffer_uint]] %[[#b:]] %[[#uint_0]]
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%casted = addrspacecast ptr addrspace(11) %ptr to ptr
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; CHECK: OpStore %[[#c]] %[[#uint_10]] Aligned 4
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store i32 10, ptr %casted, align 4
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ret void
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}
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declare ptr addrspace(11) @llvm.spv.resource.getpointer.p11.tspirv.VulkanBuffer_a0s_struct.Ss_12_1t(target("spirv.VulkanBuffer", [0 x %struct.S], 12, 1), i32)

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