[DirectX] Remove trivially dead functions at linkage finalize

llvm/lib/Target/DirectX/DXILFinalizeLinkage.cpp

@@ -19,20 +19,20 @@
 using namespace llvm;
 
 static bool finalizeLinkage(Module &M) {
-  SmallPtrSet<Function *, 8> EntriesAndExports;
+  SmallPtrSet<Function *, 8> Funcs;
 
-  // Find all entry points and export functions
+  // Collect non-entry and non-exported functions to set to internal linkage.
   for (Function &EF : M.functions()) {
-    if (!EF.hasFnAttribute("hlsl.shader") && !EF.hasFnAttribute("hlsl.export"))
+    if (EF.hasFnAttribute("hlsl.shader") || EF.hasFnAttribute("hlsl.export"))
       continue;
-    EntriesAndExports.insert(&EF);
+    Funcs.insert(&EF);
   }
 
-  for (Function &F : M.functions()) {
-    if (F.getLinkage() == GlobalValue::ExternalLinkage &&
-        !EntriesAndExports.contains(&F)) {
-      F.setLinkage(GlobalValue::InternalLinkage);
-    }
+  for (Function *F : Funcs) {
+    if (F->getLinkage() == GlobalValue::ExternalLinkage)
+      F->setLinkage(GlobalValue::InternalLinkage);
+    if (F->isDefTriviallyDead())
+      M.getFunctionList().erase(F);
   }
 
   return false;

llvm/test/CodeGen/DirectX/ShaderFlags/double-extensions.ll

@@ -9,11 +9,12 @@ target triple = "dxil-pc-shadermodel6.7-library"
 ; CHECK-NEXT: ;       Double-precision extensions for 11.1
 ; CHECK-NEXT: ; Note: extra DXIL module flags:
 ; CHECK-NEXT: {{^;$}}
-define double @div(double %a, double %b) {
+define double @div(double %a, double %b) #0 {
   %res = fdiv double %a, %b
   ret double %res
 }
 
+attributes #0 = { convergent norecurse nounwind "hlsl.export"}
 
 ; DXC: - Name:            SFI0
 ; DXC-NEXT:     Size:            8

llvm/test/CodeGen/DirectX/ShaderFlags/doubles.ll

@@ -9,11 +9,13 @@ target triple = "dxil-pc-shadermodel6.7-library"
 ; CHECK-NEXT: ; Note: extra DXIL module flags:
 ; CHECK-NEXT: {{^;$}}
 
-define double @add(double %a, double %b) {
+define double @add(double %a, double %b) #0 {
   %sum = fadd double %a, %b
   ret double %sum
 }
 
+attributes #0 = { convergent norecurse nounwind "hlsl.export"}
+
 ; DXC: - Name:            SFI0
 ; DXC-NEXT:     Size:            8
 ; DXC-NEXT:     Flags:

llvm/test/CodeGen/DirectX/conflicting-bitcast-insert.ll

@@ -1,25 +1,27 @@
 ; RUN: llc --filetype=asm %s -o - | FileCheck %s
 target triple = "dxil-unknown-shadermodel6.7-library"
 
-define i64 @test(ptr %p) {
+define i64 @test(ptr %p) #0 {
   store i32 0, ptr %p
   %v = load i64, ptr %p
   ret i64 %v
 }
 
-; CHECK: define internal i64 @test(ptr %p) {
+; CHECK: define i64 @test(ptr %p) #0 {
 ; CHECK-NEXT: %1 = bitcast ptr %p to ptr
 ; CHECK-NEXT: store i32 0, ptr %1, align 4
 ; CHECK-NEXT: %2 = bitcast ptr %p to ptr
 ; CHECK-NEXT: %3 = load i64, ptr %2, align 8
 
-define i64 @testGEP(ptr %p) {
+define i64 @testGEP(ptr %p) #0 {
   %ptr = getelementptr i32, ptr %p, i32 4
   %val = load i64, ptr %p
   ret i64 %val
 }
 
-; CHECK: define internal i64 @testGEP(ptr %p) {
+attributes #0 = { convergent norecurse nounwind "hlsl.export"}
+
+; CHECK: define i64 @testGEP(ptr %p) #0 {
 ; CHECK-NEXT:   %1 = bitcast ptr %p to ptr
 ; CHECK-NEXT:   %ptr = getelementptr i32, ptr %1, i32 4
 ; CHECK-NEXT:   %2 = bitcast ptr %p to ptr

llvm/test/CodeGen/DirectX/finalize-linkage-remove-dead-lib.ll

@@ -0,0 +1,222 @@
+; RUN: opt -S -dxil-finalize-linkage -mtriple=dxil-unknown-shadermodel6.5-library %s | FileCheck %s
+; RUN: llc %s --filetype=asm -o - | FileCheck %s
+
+target triple = "dxilv1.5-pc-shadermodel6.5-compute"
+
+; Confirm that DXILFinalizeLinkage will remove functions that have compatible
+; linkage and are not called from anywhere. This should be any function that
+; is not explicitly marked export and is not an entry point.
+
+; Has no specified inlining/linking behavior and is uncalled, this should be removed.
+; CHECK-NOT: define {{.*}}doNothingUncalled
+define void @"?doNothingUncalled@@YAXXZ"() #2 {
+entry:
+  ret void
+}
+
+; Alwaysinline and uncalled, this should be removed.
+; CHECK-NOT: define {{.*}}doAlwaysInlineUncalled
+define void @"?doAlwaysInlineUncalled@@YAXXZ"() #0 {
+entry:
+  ret void
+}
+
+; Noinline and uncalled, this should be removed.
+; CHECK-NOT: define {{.*}}doNoinlineUncalled
+define void @"?doNoinlineUncalled@@YAXXZ"() #4 {
+entry:
+  ret void
+}
+
+; No inlining attribute, internal, and uncalled; this should be removed.
+; CHECK-NOT: define {{.*}}doInternalUncalled
+define internal void @"?doInternalUncalled@@YAXXZ"() #2 {
+entry:
+  ret void
+}
+
+; Alwaysinline, internal, and uncalled; this should be removed.
+; CHECK-NOT: define {{.*}}doAlwaysInlineInternalUncalled
+define internal void @"?doAlwaysInlineInternalUncalled@@YAXXZ"() #0 {
+entry:
+  ret void
+}
+
+; Noinline, internal, and uncalled; this should be removed.
+; CHECK-NOT: define {{.*}}doNoinlineInternalUncalled
+define internal void @"?doNoinlineInternalUncalled@@YAXXZ"() #4 {
+entry:
+  ret void
+}
+
+; Marked external and uncalled, this should become internal and be removed.
+; CHECK-NOT: define {{.*}}doExternalUncalled
+define external void @"?doExternalUncalled@@YAXXZ"() #2 {
+entry:
+  ret void
+}
+
+; Alwaysinline, external and uncalled, this should become internal and be removed.
+; CHECK-NOT: define {{.*}}doAlwaysInlineExternalUncalled
+define external void @"?doAlwaysInlineExternalUncalled@@YAXXZ"() #0 {
+entry:
+  ret void
+}
+
+; Noinline, external and uncalled, this should become internal and be removed.
+; CHECK-NOT: define {{.*}}doNoinlineExternalUncalled
+define external void @"?doNoinlineExternalUncalled@@YAXXZ"() #4 {
+entry:
+  ret void
+}
+
+; No inlining attribute and called, this should stay.
+; CHECK: define {{.*}}doNothingCalled
+define void @"?doNothingCalled@@YAXXZ"() #2 {
+entry:
+  ret void
+}
+
+; Alwaysinline and called, this should stay.
+; CHECK: define {{.*}}doAlwaysInlineCalled
+define void @"?doAlwaysInlineCalled@@YAXXZ"() #0 {
+entry:
+  ret void
+}
+
+; Noinline and called, this should stay.
+; CHECK: define {{.*}}doNoinlineCalled
+define void @"?doNoinlineCalled@@YAXXZ"() #4 {
+entry:
+  ret void
+}
+
+; No inlining attribute, internal, and called; this should stay.
+; CHECK: define {{.*}}doInternalCalled
+define internal void @"?doInternalCalled@@YAXXZ"() #2 {
+entry:
+  ret void
+}
+
+; Alwaysinline, internal, and called; this should stay.
+; CHECK: define {{.*}}doAlwaysInlineInternalCalled
+define internal void @"?doAlwaysInlineInternalCalled@@YAXXZ"() #0 {
+entry:
+  ret void
+}
+
+; Noinline, internal, and called; this should stay.
+; CHECK: define {{.*}}doNoinlineInternalCalled
+define internal void @"?doNoinlineInternalCalled@@YAXXZ"() #4 {
+entry:
+  ret void
+}
+
+; Marked external and called, this should become internal and stay.
+; CHECK: define {{.*}}doExternalCalled
+define external void @"?doExternalCalled@@YAXXZ"() #2 {
+entry:
+  ret void
+}
+
+; Always inlined, external and called, this should become internal and stay.
+; CHECK: define {{.*}}doAlwaysInlineExternalCalled
+define external void @"?doAlwaysInlineExternalCalled@@YAXXZ"() #0 {
+entry:
+  ret void
+}
+
+; Noinline, external and called, this should become internal and stay.
+; CHECK: define {{.*}}doNoinlineExternalCalled
+define external void @"?doNoinlineExternalCalled@@YAXXZ"() #4 {
+entry:
+  ret void
+}
+
+; No inlining attribute and exported, this should stay.
+; CHECK: define {{.*}}doNothingExported
+define void @"?doNothingExported@@YAXXZ"() #3 {
+entry:
+  ret void
+}
+
+; Alwaysinline and exported, this should stay.
+; CHECK: define {{.*}}doAlwaysInlineExported
+define void @"?doAlwaysInlineExported@@YAXXZ"() #1 {
+entry:
+  ret void
+}
+
+; Noinline attribute and exported, this should stay.
+; CHECK: define {{.*}}doNoinlineExported
+define void @"?doNoinlineExported@@YAXXZ"() #5 {
+entry:
+  ret void
+}
+
+; No inlining attribute, internal, and exported; this should stay.
+; CHECK: define {{.*}}doInternalExported
+define internal void @"?doInternalExported@@YAXXZ"() #3 {
+entry:
+  ret void
+}
+
+; Alwaysinline, internal, and exported; this should stay.
+; CHECK: define {{.*}}doAlwaysInlineInternalExported
+define internal void @"?doAlwaysInlineInternalExported@@YAXXZ"() #1 {
+entry:
+  ret void
+}
+
+; Noinline, internal, and exported; this should stay.
+; CHECK: define {{.*}}doNoinlineInternalExported
+define internal void @"?doNoinlineInternalExported@@YAXXZ"() #5 {
+entry:
+  ret void
+}
+
+; Marked external and exported, this should stay.
+; CHECK: define {{.*}}doExternalExported
+define external void @"?doExternalExported@@YAXXZ"() #3 {
+entry:
+  ret void
+}
+
+; Alwaysinline, external and exported, this should stay.
+; CHECK: define {{.*}}doAlwaysInlineExternalExported
+define external void @"?doAlwaysInlineExternalExported@@YAXXZ"() #1 {
+entry:
+  ret void
+}
+
+; Noinline, external and exported, this should stay.
+; CHECK: define {{.*}}doNoinlineExternalExported
+define external void @"?doNoinlineExternalExported@@YAXXZ"() #5 {
+entry:
+  ret void
+}
+
+; Entry point function, this should stay.
+; CHECK: define void @main()
+define void @main() #6 {
+entry:
+  call void @"?doNothingCalled@@YAXXZ"() #7
+  call void @"?doAlwaysInlineCalled@@YAXXZ"() #7
+  call void @"?doNoinlineCalled@@YAXXZ"() #7
+  call void @"?doInternalCalled@@YAXXZ"() #7
+  call void @"?doAlwaysInlineInternalCalled@@YAXXZ"() #7
+  call void @"?doNoinlineInternalCalled@@YAXXZ"() #7
+  call void @"?doExternalCalled@@YAXXZ"() #7
+  call void @"?doAlwaysInlineExternalCalled@@YAXXZ"() #7
+  call void @"?doNoinlineExternalCalled@@YAXXZ"() #7
+  ret void
+}
+
+attributes #0 = { alwaysinline convergent norecurse nounwind }
+attributes #1 = { alwaysinline convergent norecurse nounwind "hlsl.export"}
+attributes #2 = { convergent norecurse nounwind }
+attributes #3 = { convergent norecurse nounwind "hlsl.export"}
+attributes #4 = { convergent noinline norecurse nounwind }
+attributes #5 = { convergent noinline norecurse nounwind "hlsl.export"}
+attributes #6 = { convergent noinline norecurse "hlsl.numthreads"="1,1,1" "hlsl.shader"="compute" }
+attributes #7 = { convergent }