[DirectX] Add GlobalDCE pass after finalize linkage pass in DirectX backend #151071
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@llvm/pr-subscribers-backend-directx Author: Kaitlin Peng (kmpeng) ChangesFixes #139023. This PR essentially removes unused global variables:
Full diff: https://github.com/llvm/llvm-project/pull/151071.diff 12 Files Affected:
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 31801daa126ad..0e48d80936270 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -127,6 +127,7 @@ LLVM_ABI void initializeGCEmptyBasicBlocksPass(PassRegistry &);
LLVM_ABI void initializeGCMachineCodeAnalysisPass(PassRegistry &);
LLVM_ABI void initializeGCModuleInfoPass(PassRegistry &);
LLVM_ABI void initializeGVNLegacyPassPass(PassRegistry &);
+LLVM_ABI void initializeGlobalDCELegacyPassPass(PassRegistry &);
LLVM_ABI void initializeGlobalMergeFuncPassWrapperPass(PassRegistry &);
LLVM_ABI void initializeGlobalMergePass(PassRegistry &);
LLVM_ABI void initializeGlobalsAAWrapperPassPass(PassRegistry &);
diff --git a/llvm/include/llvm/LinkAllPasses.h b/llvm/include/llvm/LinkAllPasses.h
index f82a43967e67a..7b33ec7f09124 100644
--- a/llvm/include/llvm/LinkAllPasses.h
+++ b/llvm/include/llvm/LinkAllPasses.h
@@ -38,6 +38,7 @@
#include "llvm/Support/Valgrind.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/AlwaysInliner.h"
+#include "llvm/Transforms/IPO/GlobalDCE.h"
#include "llvm/Transforms/InstCombine/InstCombine.h"
#include "llvm/Transforms/ObjCARC.h"
#include "llvm/Transforms/Scalar.h"
@@ -83,6 +84,7 @@ struct ForcePassLinking {
(void)llvm::createDomOnlyViewerWrapperPassPass();
(void)llvm::createDomViewerWrapperPassPass();
(void)llvm::createAlwaysInlinerLegacyPass();
+ (void)llvm::createGlobalDCEPass();
(void)llvm::createGlobalMergeFuncPass();
(void)llvm::createGlobalsAAWrapperPass();
(void)llvm::createInstSimplifyLegacyPass();
diff --git a/llvm/include/llvm/Transforms/IPO/GlobalDCE.h b/llvm/include/llvm/Transforms/IPO/GlobalDCE.h
index f8f775b8ea96e..55dff64889270 100644
--- a/llvm/include/llvm/Transforms/IPO/GlobalDCE.h
+++ b/llvm/include/llvm/Transforms/IPO/GlobalDCE.h
@@ -32,6 +32,7 @@ class GlobalVariable;
class Metadata;
class Module;
class Value;
+class ModulePass;
/// Pass to remove unused function declarations.
class GlobalDCEPass : public PassInfoMixin<GlobalDCEPass> {
@@ -80,6 +81,7 @@ class GlobalDCEPass : public PassInfoMixin<GlobalDCEPass> {
void ComputeDependencies(Value *V, SmallPtrSetImpl<GlobalValue *> &U);
};
+ModulePass *createGlobalDCEPass();
}
#endif // LLVM_TRANSFORMS_IPO_GLOBALDCE_H
diff --git a/llvm/lib/Target/DirectX/CMakeLists.txt b/llvm/lib/Target/DirectX/CMakeLists.txt
index c7c09caf43667..8100f941c8d94 100644
--- a/llvm/lib/Target/DirectX/CMakeLists.txt
+++ b/llvm/lib/Target/DirectX/CMakeLists.txt
@@ -49,6 +49,7 @@ add_llvm_target(DirectXCodeGen
DirectXInfo
DirectXPointerTypeAnalysis
FrontendHLSL
+ IPO
MC
ScalarOpts
SelectionDAG
diff --git a/llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp b/llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp
index 5f331dbd2d826..13e3408815bba 100644
--- a/llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp
+++ b/llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp
@@ -20,13 +20,13 @@ using namespace llvm;
static bool finalizeLinkage(Module &M) {
bool MadeChange = false;
- // Convert private global variables to internal linkage.
- for (GlobalVariable &GV : M.globals()) {
- if (GV.hasPrivateLinkage()) {
+ // Convert private globals and external globals with no usage to internal
+ // linkage.
+ for (GlobalVariable &GV : M.globals())
+ if (GV.hasPrivateLinkage() || (GV.hasExternalLinkage() && GV.use_empty())) {
GV.setLinkage(GlobalValue::InternalLinkage);
MadeChange = true;
}
- }
SmallVector<Function *> Funcs;
diff --git a/llvm/lib/Target/DirectX/DirectXPassRegistry.def b/llvm/lib/Target/DirectX/DirectXPassRegistry.def
index d5069541642b5..b4b48a166800e 100644
--- a/llvm/lib/Target/DirectX/DirectXPassRegistry.def
+++ b/llvm/lib/Target/DirectX/DirectXPassRegistry.def
@@ -24,6 +24,7 @@ MODULE_ANALYSIS("dxil-root-signature-analysis", dxil::RootSignatureAnalysis())
#define MODULE_PASS(NAME, CREATE_PASS)
#endif
MODULE_PASS("dxil-cbuffer-access", DXILCBufferAccess())
+MODULE_PASS("dxil-finalize-linkage", DXILFinalizeLinkage())
MODULE_PASS("dxil-data-scalarization", DXILDataScalarization())
MODULE_PASS("dxil-flatten-arrays", DXILFlattenArrays())
MODULE_PASS("dxil-intrinsic-expansion", DXILIntrinsicExpansion())
diff --git a/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp b/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp
index 84751d2db2266..d7609d596e444 100644
--- a/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp
+++ b/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp
@@ -14,6 +14,7 @@
#include "DirectXTargetMachine.h"
#include "DXILCBufferAccess.h"
#include "DXILDataScalarization.h"
+#include "DXILFinalizeLinkage.h"
#include "DXILFlattenArrays.h"
#include "DXILForwardHandleAccesses.h"
#include "DXILIntrinsicExpansion.h"
@@ -45,6 +46,7 @@
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Transforms/IPO/GlobalDCE.h"
#include "llvm/Transforms/Scalar/Scalarizer.h"
#include <optional>
@@ -62,6 +64,7 @@ extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeDirectXTarget() {
initializeEmbedDXILPassPass(*PR);
initializeWriteDXILPassPass(*PR);
initializeDXContainerGlobalsPass(*PR);
+ initializeGlobalDCELegacyPassPass(*PR);
initializeDXILOpLoweringLegacyPass(*PR);
initializeDXILResourceAccessLegacyPass(*PR);
initializeDXILResourceImplicitBindingLegacyPass(*PR);
@@ -103,6 +106,7 @@ class DirectXPassConfig : public TargetPassConfig {
FunctionPass *createTargetRegisterAllocator(bool) override { return nullptr; }
void addCodeGenPrepare() override {
addPass(createDXILFinalizeLinkageLegacyPass());
+ addPass(createGlobalDCEPass());
addPass(createDXILResourceAccessLegacyPass());
addPass(createDXILIntrinsicExpansionLegacyPass());
addPass(createDXILCBufferAccessLegacyPass());
diff --git a/llvm/lib/Transforms/IPO/GlobalDCE.cpp b/llvm/lib/Transforms/IPO/GlobalDCE.cpp
index 45fb1f5212b70..3812032488035 100644
--- a/llvm/lib/Transforms/IPO/GlobalDCE.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalDCE.cpp
@@ -21,6 +21,8 @@
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Utils/CtorUtils.h"
@@ -30,6 +32,36 @@ using namespace llvm;
#define DEBUG_TYPE "globaldce"
+namespace {
+class GlobalDCELegacyPass : public ModulePass {
+public:
+ static char ID; // Pass identification, replacement for typeid
+ GlobalDCELegacyPass() : ModulePass(ID) {
+ initializeGlobalDCELegacyPassPass(*PassRegistry::getPassRegistry());
+ }
+ bool runOnModule(Module &M) override {
+ if (skipModule(M))
+ return false;
+ // Note: GlobalDCEPass does not use MAM. That
+ // means we can get away with init and pass
+ // as arg.
+ ModuleAnalysisManager MAM;
+ auto PA = Impl.run(M, MAM);
+ return !PA.areAllPreserved();
+ }
+
+private:
+ GlobalDCEPass Impl;
+};
+} // namespace
+
+char GlobalDCELegacyPass::ID = 0;
+INITIALIZE_PASS(GlobalDCELegacyPass, "globaldce", "Dead Global Elimination",
+ false, false)
+
+// Public interface to the GlobalDCEPass.
+ModulePass *llvm::createGlobalDCEPass() { return new GlobalDCELegacyPass(); }
+
static cl::opt<bool>
ClEnableVFE("enable-vfe", cl::Hidden, cl::init(true),
cl::desc("Enable virtual function elimination"));
diff --git a/llvm/test/CodeGen/DirectX/finalize_linkage.ll b/llvm/test/CodeGen/DirectX/finalize_linkage.ll
index dc1140f1c9160..0e45257ba1824 100644
--- a/llvm/test/CodeGen/DirectX/finalize_linkage.ll
+++ b/llvm/test/CodeGen/DirectX/finalize_linkage.ll
@@ -1,10 +1,17 @@
-; RUN: opt -S -dxil-finalize-linkage -mtriple=dxil-unknown-shadermodel6.5-compute %s | FileCheck %s
+; RUN: opt -S -passes='dxil-finalize-linkage,globaldce' -mtriple=dxil-unknown-shadermodel6.5-compute %s | FileCheck %s
; RUN: llc %s --filetype=asm -o - | FileCheck %s --check-prefixes=CHECK-LLC
target triple = "dxilv1.5-pc-shadermodel6.5-compute"
; DXILFinalizeLinkage changes linkage of all functions that are hidden to
-; internal, and converts private global variables to internal linkage.
+; internal, converts private global variables to internal linkage, and removes
+; unused global variables.
+
+; CHECK-NOT: @aTile
+@aTile = hidden addrspace(3) global [4 x [1 x i32]] zeroinitializer, align 4
+
+; CHECK-NOT: @bTile
+@bTile = hidden addrspace(3) global [1 x <1 x i32>] zeroinitializer, align 4
; CHECK: @switch.table = internal unnamed_addr constant [4 x i32]
@switch.table = private unnamed_addr constant [4 x i32] [i32 1, i32 257, i32 65793, i32 16843009], align 4
@@ -27,6 +34,17 @@ target triple = "dxilv1.5-pc-shadermodel6.5-compute"
; CHECK: @hidden_var = hidden global i32
@hidden_var = hidden global i32 1, align 4
+define void @anchor_function() #0 {
+entry:
+ %0 = load i32, ptr @switch.table, align 4
+ %1 = load [3 x float], ptr @private_array, align 4
+ %2 = load i32, ptr @private_var, align 4
+ %3 = load i32, ptr @internal_var, align 4
+ %4 = load i32, ptr @external_var, align 4
+ %5 = load i32, ptr @hidden_var, align 4
+ ret void
+}
+
; CHECK-NOT: define internal void @"?f1@@YAXXZ"()
define void @"?f1@@YAXXZ"() #0 {
entry:
diff --git a/llvm/test/CodeGen/DirectX/llc-pipeline.ll b/llvm/test/CodeGen/DirectX/llc-pipeline.ll
index 151603a7161c5..a3a214338536f 100644
--- a/llvm/test/CodeGen/DirectX/llc-pipeline.ll
+++ b/llvm/test/CodeGen/DirectX/llc-pipeline.ll
@@ -14,6 +14,7 @@
; CHECK-NEXT: ModulePass Manager
; CHECK-NEXT: DXIL Finalize Linkage
+; CHECK-NEXT: Dead Global Elimination
; CHECK-NEXT: FunctionPass Manager
; CHECK-NEXT: DXIL Resource Access
; CHECK-NEXT: DXIL Intrinsic Expansion
diff --git a/llvm/test/CodeGen/DirectX/scalar-data.ll b/llvm/test/CodeGen/DirectX/scalar-data.ll
index 4861a0890f136..d9c8df9bc169c 100644
--- a/llvm/test/CodeGen/DirectX/scalar-data.ll
+++ b/llvm/test/CodeGen/DirectX/scalar-data.ll
@@ -1,4 +1,4 @@
-; RUN: llc %s -mtriple=dxil-pc-shadermodel6.3-library --filetype=asm -o - | FileCheck %s
+; RUN: opt -S -passes='dxil-data-scalarization,dxil-flatten-arrays' -mtriple=dxil-unknown-shadermodel6.5-compute %s | FileCheck %s
; Make sure we don't touch arrays without vectors and that can recurse and flatten multiple-dimension arrays of vectors
diff --git a/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll b/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll
index 165d5d2e520df..c53bb2127ebcc 100644
--- a/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll
+++ b/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll
@@ -7,6 +7,7 @@ target triple = "dxil-unknown-shadermodel6.7-library"
@CBV = external constant %"$Globals"
define void @main() #0 {
+ %1 = load float, ptr @CBV, align 4
ret void
}
|
|
@llvm/pr-subscribers-llvm-transforms Author: Kaitlin Peng (kmpeng) ChangesFixes #139023. This PR essentially removes unused global variables:
Full diff: https://github.com/llvm/llvm-project/pull/151071.diff 12 Files Affected:
diff --git a/llvm/include/llvm/InitializePasses.h b/llvm/include/llvm/InitializePasses.h
index 31801daa126ad..0e48d80936270 100644
--- a/llvm/include/llvm/InitializePasses.h
+++ b/llvm/include/llvm/InitializePasses.h
@@ -127,6 +127,7 @@ LLVM_ABI void initializeGCEmptyBasicBlocksPass(PassRegistry &);
LLVM_ABI void initializeGCMachineCodeAnalysisPass(PassRegistry &);
LLVM_ABI void initializeGCModuleInfoPass(PassRegistry &);
LLVM_ABI void initializeGVNLegacyPassPass(PassRegistry &);
+LLVM_ABI void initializeGlobalDCELegacyPassPass(PassRegistry &);
LLVM_ABI void initializeGlobalMergeFuncPassWrapperPass(PassRegistry &);
LLVM_ABI void initializeGlobalMergePass(PassRegistry &);
LLVM_ABI void initializeGlobalsAAWrapperPassPass(PassRegistry &);
diff --git a/llvm/include/llvm/LinkAllPasses.h b/llvm/include/llvm/LinkAllPasses.h
index f82a43967e67a..7b33ec7f09124 100644
--- a/llvm/include/llvm/LinkAllPasses.h
+++ b/llvm/include/llvm/LinkAllPasses.h
@@ -38,6 +38,7 @@
#include "llvm/Support/Valgrind.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/AlwaysInliner.h"
+#include "llvm/Transforms/IPO/GlobalDCE.h"
#include "llvm/Transforms/InstCombine/InstCombine.h"
#include "llvm/Transforms/ObjCARC.h"
#include "llvm/Transforms/Scalar.h"
@@ -83,6 +84,7 @@ struct ForcePassLinking {
(void)llvm::createDomOnlyViewerWrapperPassPass();
(void)llvm::createDomViewerWrapperPassPass();
(void)llvm::createAlwaysInlinerLegacyPass();
+ (void)llvm::createGlobalDCEPass();
(void)llvm::createGlobalMergeFuncPass();
(void)llvm::createGlobalsAAWrapperPass();
(void)llvm::createInstSimplifyLegacyPass();
diff --git a/llvm/include/llvm/Transforms/IPO/GlobalDCE.h b/llvm/include/llvm/Transforms/IPO/GlobalDCE.h
index f8f775b8ea96e..55dff64889270 100644
--- a/llvm/include/llvm/Transforms/IPO/GlobalDCE.h
+++ b/llvm/include/llvm/Transforms/IPO/GlobalDCE.h
@@ -32,6 +32,7 @@ class GlobalVariable;
class Metadata;
class Module;
class Value;
+class ModulePass;
/// Pass to remove unused function declarations.
class GlobalDCEPass : public PassInfoMixin<GlobalDCEPass> {
@@ -80,6 +81,7 @@ class GlobalDCEPass : public PassInfoMixin<GlobalDCEPass> {
void ComputeDependencies(Value *V, SmallPtrSetImpl<GlobalValue *> &U);
};
+ModulePass *createGlobalDCEPass();
}
#endif // LLVM_TRANSFORMS_IPO_GLOBALDCE_H
diff --git a/llvm/lib/Target/DirectX/CMakeLists.txt b/llvm/lib/Target/DirectX/CMakeLists.txt
index c7c09caf43667..8100f941c8d94 100644
--- a/llvm/lib/Target/DirectX/CMakeLists.txt
+++ b/llvm/lib/Target/DirectX/CMakeLists.txt
@@ -49,6 +49,7 @@ add_llvm_target(DirectXCodeGen
DirectXInfo
DirectXPointerTypeAnalysis
FrontendHLSL
+ IPO
MC
ScalarOpts
SelectionDAG
diff --git a/llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp b/llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp
index 5f331dbd2d826..13e3408815bba 100644
--- a/llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp
+++ b/llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp
@@ -20,13 +20,13 @@ using namespace llvm;
static bool finalizeLinkage(Module &M) {
bool MadeChange = false;
- // Convert private global variables to internal linkage.
- for (GlobalVariable &GV : M.globals()) {
- if (GV.hasPrivateLinkage()) {
+ // Convert private globals and external globals with no usage to internal
+ // linkage.
+ for (GlobalVariable &GV : M.globals())
+ if (GV.hasPrivateLinkage() || (GV.hasExternalLinkage() && GV.use_empty())) {
GV.setLinkage(GlobalValue::InternalLinkage);
MadeChange = true;
}
- }
SmallVector<Function *> Funcs;
diff --git a/llvm/lib/Target/DirectX/DirectXPassRegistry.def b/llvm/lib/Target/DirectX/DirectXPassRegistry.def
index d5069541642b5..b4b48a166800e 100644
--- a/llvm/lib/Target/DirectX/DirectXPassRegistry.def
+++ b/llvm/lib/Target/DirectX/DirectXPassRegistry.def
@@ -24,6 +24,7 @@ MODULE_ANALYSIS("dxil-root-signature-analysis", dxil::RootSignatureAnalysis())
#define MODULE_PASS(NAME, CREATE_PASS)
#endif
MODULE_PASS("dxil-cbuffer-access", DXILCBufferAccess())
+MODULE_PASS("dxil-finalize-linkage", DXILFinalizeLinkage())
MODULE_PASS("dxil-data-scalarization", DXILDataScalarization())
MODULE_PASS("dxil-flatten-arrays", DXILFlattenArrays())
MODULE_PASS("dxil-intrinsic-expansion", DXILIntrinsicExpansion())
diff --git a/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp b/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp
index 84751d2db2266..d7609d596e444 100644
--- a/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp
+++ b/llvm/lib/Target/DirectX/DirectXTargetMachine.cpp
@@ -14,6 +14,7 @@
#include "DirectXTargetMachine.h"
#include "DXILCBufferAccess.h"
#include "DXILDataScalarization.h"
+#include "DXILFinalizeLinkage.h"
#include "DXILFlattenArrays.h"
#include "DXILForwardHandleAccesses.h"
#include "DXILIntrinsicExpansion.h"
@@ -45,6 +46,7 @@
#include "llvm/Support/Compiler.h"
#include "llvm/Support/ErrorHandling.h"
#include "llvm/Target/TargetLoweringObjectFile.h"
+#include "llvm/Transforms/IPO/GlobalDCE.h"
#include "llvm/Transforms/Scalar/Scalarizer.h"
#include <optional>
@@ -62,6 +64,7 @@ extern "C" LLVM_EXTERNAL_VISIBILITY void LLVMInitializeDirectXTarget() {
initializeEmbedDXILPassPass(*PR);
initializeWriteDXILPassPass(*PR);
initializeDXContainerGlobalsPass(*PR);
+ initializeGlobalDCELegacyPassPass(*PR);
initializeDXILOpLoweringLegacyPass(*PR);
initializeDXILResourceAccessLegacyPass(*PR);
initializeDXILResourceImplicitBindingLegacyPass(*PR);
@@ -103,6 +106,7 @@ class DirectXPassConfig : public TargetPassConfig {
FunctionPass *createTargetRegisterAllocator(bool) override { return nullptr; }
void addCodeGenPrepare() override {
addPass(createDXILFinalizeLinkageLegacyPass());
+ addPass(createGlobalDCEPass());
addPass(createDXILResourceAccessLegacyPass());
addPass(createDXILIntrinsicExpansionLegacyPass());
addPass(createDXILCBufferAccessLegacyPass());
diff --git a/llvm/lib/Transforms/IPO/GlobalDCE.cpp b/llvm/lib/Transforms/IPO/GlobalDCE.cpp
index 45fb1f5212b70..3812032488035 100644
--- a/llvm/lib/Transforms/IPO/GlobalDCE.cpp
+++ b/llvm/lib/Transforms/IPO/GlobalDCE.cpp
@@ -21,6 +21,8 @@
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Pass.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/Utils/CtorUtils.h"
@@ -30,6 +32,36 @@ using namespace llvm;
#define DEBUG_TYPE "globaldce"
+namespace {
+class GlobalDCELegacyPass : public ModulePass {
+public:
+ static char ID; // Pass identification, replacement for typeid
+ GlobalDCELegacyPass() : ModulePass(ID) {
+ initializeGlobalDCELegacyPassPass(*PassRegistry::getPassRegistry());
+ }
+ bool runOnModule(Module &M) override {
+ if (skipModule(M))
+ return false;
+ // Note: GlobalDCEPass does not use MAM. That
+ // means we can get away with init and pass
+ // as arg.
+ ModuleAnalysisManager MAM;
+ auto PA = Impl.run(M, MAM);
+ return !PA.areAllPreserved();
+ }
+
+private:
+ GlobalDCEPass Impl;
+};
+} // namespace
+
+char GlobalDCELegacyPass::ID = 0;
+INITIALIZE_PASS(GlobalDCELegacyPass, "globaldce", "Dead Global Elimination",
+ false, false)
+
+// Public interface to the GlobalDCEPass.
+ModulePass *llvm::createGlobalDCEPass() { return new GlobalDCELegacyPass(); }
+
static cl::opt<bool>
ClEnableVFE("enable-vfe", cl::Hidden, cl::init(true),
cl::desc("Enable virtual function elimination"));
diff --git a/llvm/test/CodeGen/DirectX/finalize_linkage.ll b/llvm/test/CodeGen/DirectX/finalize_linkage.ll
index dc1140f1c9160..0e45257ba1824 100644
--- a/llvm/test/CodeGen/DirectX/finalize_linkage.ll
+++ b/llvm/test/CodeGen/DirectX/finalize_linkage.ll
@@ -1,10 +1,17 @@
-; RUN: opt -S -dxil-finalize-linkage -mtriple=dxil-unknown-shadermodel6.5-compute %s | FileCheck %s
+; RUN: opt -S -passes='dxil-finalize-linkage,globaldce' -mtriple=dxil-unknown-shadermodel6.5-compute %s | FileCheck %s
; RUN: llc %s --filetype=asm -o - | FileCheck %s --check-prefixes=CHECK-LLC
target triple = "dxilv1.5-pc-shadermodel6.5-compute"
; DXILFinalizeLinkage changes linkage of all functions that are hidden to
-; internal, and converts private global variables to internal linkage.
+; internal, converts private global variables to internal linkage, and removes
+; unused global variables.
+
+; CHECK-NOT: @aTile
+@aTile = hidden addrspace(3) global [4 x [1 x i32]] zeroinitializer, align 4
+
+; CHECK-NOT: @bTile
+@bTile = hidden addrspace(3) global [1 x <1 x i32>] zeroinitializer, align 4
; CHECK: @switch.table = internal unnamed_addr constant [4 x i32]
@switch.table = private unnamed_addr constant [4 x i32] [i32 1, i32 257, i32 65793, i32 16843009], align 4
@@ -27,6 +34,17 @@ target triple = "dxilv1.5-pc-shadermodel6.5-compute"
; CHECK: @hidden_var = hidden global i32
@hidden_var = hidden global i32 1, align 4
+define void @anchor_function() #0 {
+entry:
+ %0 = load i32, ptr @switch.table, align 4
+ %1 = load [3 x float], ptr @private_array, align 4
+ %2 = load i32, ptr @private_var, align 4
+ %3 = load i32, ptr @internal_var, align 4
+ %4 = load i32, ptr @external_var, align 4
+ %5 = load i32, ptr @hidden_var, align 4
+ ret void
+}
+
; CHECK-NOT: define internal void @"?f1@@YAXXZ"()
define void @"?f1@@YAXXZ"() #0 {
entry:
diff --git a/llvm/test/CodeGen/DirectX/llc-pipeline.ll b/llvm/test/CodeGen/DirectX/llc-pipeline.ll
index 151603a7161c5..a3a214338536f 100644
--- a/llvm/test/CodeGen/DirectX/llc-pipeline.ll
+++ b/llvm/test/CodeGen/DirectX/llc-pipeline.ll
@@ -14,6 +14,7 @@
; CHECK-NEXT: ModulePass Manager
; CHECK-NEXT: DXIL Finalize Linkage
+; CHECK-NEXT: Dead Global Elimination
; CHECK-NEXT: FunctionPass Manager
; CHECK-NEXT: DXIL Resource Access
; CHECK-NEXT: DXIL Intrinsic Expansion
diff --git a/llvm/test/CodeGen/DirectX/scalar-data.ll b/llvm/test/CodeGen/DirectX/scalar-data.ll
index 4861a0890f136..d9c8df9bc169c 100644
--- a/llvm/test/CodeGen/DirectX/scalar-data.ll
+++ b/llvm/test/CodeGen/DirectX/scalar-data.ll
@@ -1,4 +1,4 @@
-; RUN: llc %s -mtriple=dxil-pc-shadermodel6.3-library --filetype=asm -o - | FileCheck %s
+; RUN: opt -S -passes='dxil-data-scalarization,dxil-flatten-arrays' -mtriple=dxil-unknown-shadermodel6.5-compute %s | FileCheck %s
; Make sure we don't touch arrays without vectors and that can recurse and flatten multiple-dimension arrays of vectors
diff --git a/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll b/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll
index 165d5d2e520df..c53bb2127ebcc 100644
--- a/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll
+++ b/llvm/test/tools/dxil-dis/opaque-value_as_metadata.ll
@@ -7,6 +7,7 @@ target triple = "dxil-unknown-shadermodel6.7-library"
@CBV = external constant %"$Globals"
define void @main() #0 {
+ %1 = load float, ptr @CBV, align 4
ret void
}
|
farzonl
reviewed
Jul 29, 2025
| // Convert private globals and external globals with no usage to internal | ||
| // linkage. | ||
| for (GlobalVariable &GV : M.globals()) | ||
| if (GV.hasPrivateLinkage() || (GV.hasExternalLinkage() && GV.use_empty())) { |
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For anyone else looking this is the crux of the change right here. GlobalDCE is conservative so it won't remove globals marked external. This is because Linker would handle these globals and usually something like the internalizer pass would run and do a similar conversion to what we are doing here.
In HLSL's case after finalize linkage we should be able to assume that it is safe to mark all external globals with no uses as internal. If we then run GlobalDCE after this these globals will get cleaned up.
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If we're just concerned with deleting unused external variables... we could do that as part of DXILFinalizeLinkage instead of running GlobalDCE in the backend.
Are there other cases that GlobalDCE catches that we need to catch late?
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Justin suggested we not do special casing of global_ctors and that GlobalDCE was a more complete solution. Hence why we closed the previous attempt at fixing this issue.
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We need to special case global constructors for library shaders. That's not optional.
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If we use GlobalDCE we don't need to special case, things just work by converting to internal.
bogner
reviewed
Aug 6, 2025
| @@ -1,4 +1,4 @@ | |||
| ; RUN: llc %s -mtriple=dxil-pc-shadermodel6.3-library --filetype=asm -o - | FileCheck %s | |||
| ; RUN: opt -S -passes='dxil-data-scalarization,dxil-flatten-arrays' -mtriple=dxil-unknown-shadermodel6.5-compute %s | FileCheck %s | |||
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Would it be better to modify the linkage of the globals in this test to be external rather than changing how we test this?
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@farzonl suggested changing it to opt - do you have thoughts on this?
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Yeah switched to opt b\c globalDCE would eliminate globals that were being used in this test.
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I meant do you have thoughts on if it would be better to modify the linkages instead of changing to opt?
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This test case is intended to be very limited to the effects of the array flattening and vector scalarization passes. Even if we change the linkage to external it would still get cleaned up by Global DCE. Since we know which two passes are responsible for the data transformations I think its fine to just run those two passes.
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…ved by globaldce, fix tests
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I did a run of the DML Shaders today. There are currently only two validator errors left and none of them are The remaining two validation issues: @Icohedron are you aware of any changes that went in that could have impacted these validation issues? Is it possible the bitcast errors are masking the unused errors? @bogner should we hold off on this pr? |
No, I am not aware of any changes that could have impacted these validation issues. I also don't think the bitcast errors are masking the unused errors because they used to coexist. |
Also there is a third remaining validation issue: 120 occurrences of This validation issue could be masking the unused errors. |
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Fixes #139023.
This PR essentially removes unused global variables:
GlobalDCELegacy pass and adds it to the DirectX backend after the finalize linkage passGlobalDCE)dxil-finalize-linkagepass usable using the new pass manager flag syntaxfinalize_linkage.llthat make sure unused global variables are removed@CBVinopaque-value_as_metadata.llso it isn't removedscalar-data.llrun command to avoid removing its global variables