[HLSL] Appropriately set function attribute optnone #125937

bharadwajy · 2025-02-05T21:31:48Z

When optimization is disabled, set optnone attribute all module entry functions.

Updated test in accordance with the change.

With this change, the plan is to eliminate generation of non-standard DXIL metadata dx.disable_optimizations and use the function attribute to detect setting of shader flag DisableOptimizations in a follow-on PR with these changes to address issues #124796 and #112263.

Closes #124796

llvmbot · 2025-02-05T21:32:35Z

@llvm/pr-subscribers-hlsl

@llvm/pr-subscribers-clang-codegen

Author: S. Bharadwaj Yadavalli (bharadwajy)

Changes

When optimization is disabled, set optnone attribute

for all module functions when targetting library shaders
only for entry function when targetting non-library shaders

Updated tests in accordance with the change.

With this change, generation of non-standard DXIL metadata dx.disable_optimizations is planned to be eliminated (#124796) in a follow-on PR.

Patch is 25.53 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/125937.diff

10 Files Affected:

(modified) clang/lib/CodeGen/CodeGenModule.cpp (+10-1)
(modified) clang/test/CodeGenHLSL/GlobalConstructorFunction.hlsl (+2-3)
(modified) clang/test/CodeGenHLSL/GlobalConstructorLib.hlsl (+4-4)
(modified) clang/test/CodeGenHLSL/GlobalDestructors.hlsl (+2-2)
(modified) clang/test/CodeGenHLSL/builtins/RWBuffer-subscript.hlsl (+2-1)
(modified) clang/test/CodeGenHLSL/builtins/StructuredBuffers-subscripts.hlsl (+1-2)
(modified) clang/test/CodeGenHLSL/implicit-norecurse-attrib.hlsl (+18-13)
(modified) clang/test/CodeGenHLSL/inline-constructors.hlsl (+8-6)
(modified) clang/test/CodeGenHLSL/inline-functions.hlsl (+113-45)
(modified) clang/test/CodeGenHLSL/this-assignment-overload.hlsl (+4-2)

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 02615bb13dfb8a7..42cb7d8634a24b2 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -2545,7 +2545,16 @@ void CodeGenModule::SetLLVMFunctionAttributesForDefinition(const Decl *D,
   // Non-entry HLSL functions must always be inlined.
   if (getLangOpts().HLSL && !F->hasFnAttribute(llvm::Attribute::NoInline) &&
       !D->hasAttr<NoInlineAttr>()) {
-    B.addAttribute(llvm::Attribute::AlwaysInline);
+    // Set OptimizeNone for HLSL entry functions if ShouldAddOptNone
+    // or for all HLSL functions compiled for Library target.
+    llvm::Triple T(F->getParent()->getTargetTriple());
+    if (ShouldAddOptNone &&
+        (D->hasAttr<HLSLShaderAttr>() ||
+         T.getEnvironment() == llvm::Triple::EnvironmentType::Library)) {
+      B.addAttribute(llvm::Attribute::OptimizeNone);
+      B.addAttribute(llvm::Attribute::NoInline);
+    } else
+      B.addAttribute(llvm::Attribute::AlwaysInline);
   } else if ((ShouldAddOptNone || D->hasAttr<OptimizeNoneAttr>()) &&
              !F->hasFnAttribute(llvm::Attribute::AlwaysInline)) {
     // Add optnone, but do so only if the function isn't always_inline.
diff --git a/clang/test/CodeGenHLSL/GlobalConstructorFunction.hlsl b/clang/test/CodeGenHLSL/GlobalConstructorFunction.hlsl
index c0eb1b138ed0475..e880ec93c634ed5 100644
--- a/clang/test/CodeGenHLSL/GlobalConstructorFunction.hlsl
+++ b/clang/test/CodeGenHLSL/GlobalConstructorFunction.hlsl
@@ -32,11 +32,10 @@ void main(unsigned GI : SV_GroupIndex) {}
 // NOINLINE-NEXT:   call void @_Z12call_me_lastv(
 // NOINLINE-NEXT:   ret void
 
-// Verify constructor calls are inlined when AlwaysInline is run
-// INLINE-NEXT:   alloca
+// Verify constructor calls are inlined
 // INLINE-NEXT:   store i32 12
 // INLINE-NEXT:   store i32 13
 // INLINE-NEXT:   %0 = call i32 @llvm.dx.flattened.thread.id.in.group()
-// INLINE-NEXT:   store i32 %
+// INLINE-NEXT:   call void @_Z4mainj(i32 %0)
 // INLINE-NEXT:   store i32 0
 // INLINE:   ret void
diff --git a/clang/test/CodeGenHLSL/GlobalConstructorLib.hlsl b/clang/test/CodeGenHLSL/GlobalConstructorLib.hlsl
index 09c44f6242c53c7..39d7c73e832a104 100644
--- a/clang/test/CodeGenHLSL/GlobalConstructorLib.hlsl
+++ b/clang/test/CodeGenHLSL/GlobalConstructorLib.hlsl
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -emit-llvm -disable-llvm-passes %s -o - | FileCheck %s --check-prefixes=CHECK,NOINLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -emit-llvm -O0 %s -o - | FileCheck %s --check-prefixes=CHECK,INLINE
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -emit-llvm -O1 %s -o - | FileCheck %s --check-prefixes=CHECK,INLINE
 
 // Make sure global variable for ctors exist for lib profile.
 // CHECK:@llvm.global_ctors
@@ -31,12 +31,12 @@ void SecondEntry() {}
 // CHECK: ret void
 
 
-// Verify the constructor is alwaysinline
-// NOINLINE: ; Function Attrs: {{.*}}alwaysinline
+// Verify the constructor is optnone
+// NOINLINE: ; Function Attrs: {{.*}} optnone
 // NOINLINE-NEXT: define linkonce_odr void @_ZN4hlsl8RWBufferIfEC2Ev({{.*}} [[CtorAttr:\#[0-9]+]]
 
 // NOINLINE: ; Function Attrs: {{.*}}alwaysinline
 // NOINLINE-NEXT: define internal void @_GLOBAL__sub_I_GlobalConstructorLib.hlsl() [[InitAttr:\#[0-9]+]]
 
 // NOINLINE-DAG: attributes [[InitAttr]] = {{.*}} alwaysinline
-// NOINLINE-DAG: attributes [[CtorAttr]] = {{.*}} alwaysinline
+// NOINLINE-DAG: attributes [[CtorAttr]] = {{.*}} optnone
diff --git a/clang/test/CodeGenHLSL/GlobalDestructors.hlsl b/clang/test/CodeGenHLSL/GlobalDestructors.hlsl
index f98318601134bb2..8961e1a7e59cd9c 100644
--- a/clang/test/CodeGenHLSL/GlobalDestructors.hlsl
+++ b/clang/test/CodeGenHLSL/GlobalDestructors.hlsl
@@ -1,7 +1,7 @@
 // RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -emit-llvm -disable-llvm-passes %s -o - | FileCheck %s --check-prefixes=CS,NOINLINE,CHECK
 // RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -emit-llvm -disable-llvm-passes %s -o - | FileCheck %s --check-prefixes=LIB,NOINLINE,CHECK
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -emit-llvm -O0 %s -o - | FileCheck %s --check-prefixes=INLINE,CHECK
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -emit-llvm -O0 %s -o - | FileCheck %s --check-prefixes=INLINE,CHECK
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -emit-llvm -O1 %s -o - | FileCheck %s --check-prefixes=INLINE,CHECK
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -emit-llvm -O1 %s -o - | FileCheck %s --check-prefixes=INLINE,CHECK
 
 // Tests that constructors and destructors are appropriately generated for globals
 // and that their calls are inlined when AlwaysInline is run
diff --git a/clang/test/CodeGenHLSL/builtins/RWBuffer-subscript.hlsl b/clang/test/CodeGenHLSL/builtins/RWBuffer-subscript.hlsl
index 2ad5b82a029129f..9c9532da426c961 100644
--- a/clang/test/CodeGenHLSL/builtins/RWBuffer-subscript.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/RWBuffer-subscript.hlsl
@@ -6,7 +6,8 @@ RWBuffer<int> Out;
 
 [numthreads(1,1,1)]
 void main(unsigned GI : SV_GroupIndex) {
-  // CHECK: define void @main()
+  // DXC: define internal void @_Z4mainj(i32 noundef %GI)
+  // SPIRV: define internal spir_func void @_Z4mainj(i32 noundef %GI)
 
   // DXC: %[[INPTR:.*]] = call noundef nonnull align 4 dereferenceable(4) ptr @llvm.dx.resource.getpointer.p0.tdx.TypedBuffer_i32_1_0_1t(target("dx.TypedBuffer", i32, 1, 0, 1) %{{.*}}, i32 %{{.*}})
   // SPIRV: %[[INPTR:.*]] = call noundef nonnull align 4 dereferenceable(4) ptr @llvm.spv.resource.getpointer.p0.tspirv.Image_i32_5_2_0_0_2_0t(target("spirv.Image", i32, 5, 2, 0, 0, 2, 0) %{{.*}}, i32 %{{.*}})
diff --git a/clang/test/CodeGenHLSL/builtins/StructuredBuffers-subscripts.hlsl b/clang/test/CodeGenHLSL/builtins/StructuredBuffers-subscripts.hlsl
index 2af7c3ed3219ffc..c3a8225720670fc 100644
--- a/clang/test/CodeGenHLSL/builtins/StructuredBuffers-subscripts.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/StructuredBuffers-subscripts.hlsl
@@ -6,8 +6,7 @@ RasterizerOrderedStructuredBuffer<int> Out2;
 
 [numthreads(1,1,1)]
 void main(unsigned GI : SV_GroupIndex) {
-  // CHECK: define void @main()
-
+  // CHECK: define internal void @_Z4mainj(i32 noundef %GI)
   // CHECK: %[[INPTR:.*]] = call noundef nonnull align 4 dereferenceable(4) ptr @llvm.dx.resource.getpointer.p0.tdx.RawBuffer_i32_0_0t(target("dx.RawBuffer", i32, 0, 0) %{{.*}}, i32 %{{.*}})
   // CHECK: %[[LOAD:.*]] = load i32, ptr %[[INPTR]]
   // CHECK: %[[OUT1PTR:.*]] = call noundef nonnull align 4 dereferenceable(4) ptr @llvm.dx.resource.getpointer.p0.tdx.RawBuffer_i32_1_0t(target("dx.RawBuffer", i32, 1, 0) %{{.*}}, i32 %{{.*}})
diff --git a/clang/test/CodeGenHLSL/implicit-norecurse-attrib.hlsl b/clang/test/CodeGenHLSL/implicit-norecurse-attrib.hlsl
index a8ab6ce98ae7e96..415a78ceabd98b9 100644
--- a/clang/test/CodeGenHLSL/implicit-norecurse-attrib.hlsl
+++ b/clang/test/CodeGenHLSL/implicit-norecurse-attrib.hlsl
@@ -1,5 +1,5 @@
-// RUN: %clang_cc1 -x hlsl -triple dxil-pc-shadermodel6.3-library  -finclude-default-header %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s
-// RUN: %clang_cc1 -x hlsl -triple dxil-pc-shadermodel6.0-compute  -finclude-default-header %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s
+// RUN: %clang_cc1 -x hlsl -triple dxil-pc-shadermodel6.3-library  -finclude-default-header %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s --check-prefixes=CHECK,LIB
+// RUN: %clang_cc1 -x hlsl -triple dxil-pc-shadermodel6.0-compute  -finclude-default-header %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s --check-prefixes=CHECK,COMPUTE
 
 // Verify that a few different function types all get the NoRecurse attribute
 
@@ -11,7 +11,8 @@ struct Node {
   uint left, right;
 };
 
-// CHECK: Function Attrs:{{.*}}norecurse
+// LIB: Function Attrs:{{.*}}norecurse{{.*}}optnone
+// COMPUTE: Function Attrs: alwaysinline{{.*}}norecurse
 // CHECK: define noundef i32 @_Z4FindA100_4Nodej(ptr noundef byval([100 x %struct.Node]) align 4 %SortedTree, i32 noundef %key) [[IntAttr:\#[0-9]+]]
 // CHECK: ret i32
 // Find and return value corresponding to key in the SortedTree
@@ -30,7 +31,8 @@ uint Find(Node SortedTree[MAX], uint key) {
   }
 }
 
-// CHECK: Function Attrs:{{.*}}norecurse
+// LIB: Function Attrs:{{.*}}norecurse{{.*}}optnone
+// COMPUTE: Function Attrs: alwaysinline{{.*}}norecurse
 // CHECK: define noundef i1 @_Z8InitTreeA100_4NodeN4hlsl8RWBufferIDv4_jEEj(ptr noundef byval([100 x %struct.Node]) align 4 %tree, ptr noundef byval(%"class.hlsl::RWBuffer") align 4 %encodedTree, i32 noundef %maxDepth) [[ExtAttr:\#[0-9]+]]
 // CHECK: ret i1
 // Initialize tree with given buffer
@@ -51,12 +53,13 @@ bool InitTree(/*inout*/ Node tree[MAX], RWBuffer<uint4> encodedTree, uint maxDep
 RWBuffer<uint4> gTree;
 
 // Mangled entry points are internal
-// CHECK: Function Attrs:{{.*}}norecurse
-// CHECK: define internal void @_Z4mainj(i32 noundef %GI) [[IntAttr]]
+// CHECK: Function Attrs:{{.*}}norecurse{{.*}}optnone
+// LIB: define internal void @_Z4mainj(i32 noundef %GI) [[IntAttr]]
+// COMPUTE: define internal void @_Z4mainj(i32 noundef %GI) [[IntComputeAttr:\#[0-9]]]
 // CHECK: ret void
 
 // Canonical entry points are external and shader attributed
-// CHECK: Function Attrs:{{.*}}norecurse
+// CHECK: Function Attrs: convergent noinline norecurse
 // CHECK: define void @main() [[EntryAttr:\#[0-9]+]]
 // CHECK: ret void
 
@@ -70,12 +73,13 @@ void main(uint GI : SV_GroupIndex) {
 }
 
 // Mangled entry points are internal
-// CHECK: Function Attrs:{{.*}}norecurse
-// CHECK: define internal void @_Z11defaultMainv() [[IntAttr]]
+// CHECK: Function Attrs:{{.*}}norecurse{{.*}}optnone
+// LIB: define internal void @_Z11defaultMainv() [[IntAttr]]
+// COMPUTE: define internal void @_Z11defaultMainv() [[IntComputeAttr]]
 // CHECK: ret void
 
 // Canonical entry points are external and shader attributed
-// CHECK: Function Attrs:{{.*}}norecurse
+// CHECK: Function Attrs: convergent noinline norecurse
 // CHECK: define void @defaultMain() [[EntryAttr]]
 // CHECK: ret void
 
@@ -88,6 +92,7 @@ void defaultMain() {
     needle = Find(haystack, needle);
 }
 
-// CHECK: attributes [[IntAttr]] = {{.*}} norecurse
-// CHECK: attributes [[ExtAttr]] = {{.*}} norecurse
-// CHECK: attributes [[EntryAttr]] = {{.*}} norecurse
+// CHECK: attributes [[IntAttr]] = {{.*}}norecurse
+// CHECK: attributes [[ExtAttr]] = {{.*}}norecurse
+// COMPUTE: attributes [[IntComputeAttr]] = {{.*}}norecurse
+// CHECK: attributes [[EntryAttr]] = {{.*}}norecurse
\ No newline at end of file
diff --git a/clang/test/CodeGenHLSL/inline-constructors.hlsl b/clang/test/CodeGenHLSL/inline-constructors.hlsl
index b0d5a783fb3725c..340146321509cbe 100644
--- a/clang/test/CodeGenHLSL/inline-constructors.hlsl
+++ b/clang/test/CodeGenHLSL/inline-constructors.hlsl
@@ -1,9 +1,9 @@
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -std=hlsl202x -emit-llvm -o - -disable-llvm-passes %s | FileCheck %s --check-prefixes=CHECK,NOINLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -std=hlsl202x -emit-llvm -o - -disable-llvm-passes %s | FileCheck %s --check-prefixes=CHECK,NOINLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -std=hlsl202x -emit-llvm -o - -O0 %s | FileCheck %s --check-prefixes=CHECK,INLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -std=hlsl202x -emit-llvm -o - -O0 %s | FileCheck %s --check-prefixes=CHECK,INLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -std=hlsl202x -emit-llvm -o - -O1 %s | FileCheck %s --check-prefixes=CHECK,INLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -std=hlsl202x -emit-llvm -o - -O1 %s | FileCheck %s --check-prefixes=CHECK,INLINE
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -std=hlsl202x -Wno-hlsl-extensions -emit-llvm -o - -disable-llvm-passes %s | FileCheck %s --check-prefixes=CHECK,NOINLINE
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -std=hlsl202x -Wno-hlsl-extensions -emit-llvm -o - -disable-llvm-passes %s | FileCheck %s --check-prefixes=CHECK,NOINLINE
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -std=hlsl202x -Wno-hlsl-extensions -emit-llvm -o - -O0 %s | FileCheck %s --check-prefixes=CHECK,NOINLINE_INTERNAL
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -std=hlsl202x -Wno-hlsl-extensions -emit-llvm -o - -O0 %s | FileCheck %s --check-prefixes=CHECK,NOINLINE_INTERNAL
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute -std=hlsl202x -Wno-hlsl-extensions -emit-llvm -o - -O1 %s | FileCheck %s --check-prefixes=CHECK,INLINE
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library -std=hlsl202x -Wno-hlsl-extensions -emit-llvm -o - -O1 %s | FileCheck %s --check-prefixes=CHECK,INLINE
 
 // Tests that implicit constructor calls for user classes will always be inlined.
 
@@ -67,6 +67,8 @@ void main(unsigned GI : SV_GroupIndex) {
 // NOINLINE-NEXT:   call void @_Z9rainyMainv()
 // Verify inlining leaves only calls to "llvm." intrinsics
 // INLINE-NOT:      call {{[^@]*}} @{{[^l][^l][^v][^m][^\.]}}
+// Verify internal function is not inlined
+// NOINLINE_INTERNAL: call void @_Z9rainyMainv()
 // CHECK:           ret void
 [shader("compute")]
 [numthreads(1,1,1)]
diff --git a/clang/test/CodeGenHLSL/inline-functions.hlsl b/clang/test/CodeGenHLSL/inline-functions.hlsl
index e78d04ec9594fac..25b89c7b0289625 100644
--- a/clang/test/CodeGenHLSL/inline-functions.hlsl
+++ b/clang/test/CodeGenHLSL/inline-functions.hlsl
@@ -1,22 +1,31 @@
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s --check-prefixes=CHECK,NOINLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library %s -emit-llvm -O0 -o - | FileCheck %s --check-prefixes=CHECK,INLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library %s -emit-llvm -O1 -o - | FileCheck %s --check-prefixes=CHECK,INLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s --check-prefixes=CHECK,NOINLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute %s -emit-llvm -O0 -o - | FileCheck %s --check-prefixes=CHECK,INLINE
-// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute %s -emit-llvm -O1 -o - | FileCheck %s --check-prefixes=CHECK,INLINE
-
-// Tests that user functions will always be inlined.
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s --check-prefixes=CHECK,CHECK_LIB_OPTNONE
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library %s -emit-llvm -O0 -o - | FileCheck %s --check-prefixes=CHECK,CHECK_LIB_OPTNONE
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.3-library %s -emit-llvm -O1 -o - | FileCheck %s --check-prefixes=CHECK,CHECK_OPT
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute %s -emit-llvm -disable-llvm-passes -o - | FileCheck %s --check-prefixes=CHECK,CHECK_CS_OPTNONE
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute %s -emit-llvm -O0 -o - | FileCheck %s --check-prefixes=CHECK,CHECK_CS_OPTNONE
+// RUN: %clang_cc1 -triple dxil-pc-shadermodel6.0-compute %s -emit-llvm -O1 -o - | FileCheck %s --check-prefixes=CHECK,CHECK_OPT
+
+// Tests inlining of user functions based on specified optimization options.
 // This includes exported functions and mangled entry point implementation functions.
-// The unmangled entry functions must not be alwaysinlined.
 
 #define MAX 100
 
 float nums[MAX];
 
-// Verify that all functions have the alwaysinline attribute
-// NOINLINE: Function Attrs: alwaysinline
-// NOINLINE: define void @_Z4swapA100_jjj(ptr noundef byval([100 x i32]) align 4 %Buf, i32 noundef %ix1, i32 noundef %ix2) [[IntAttr:\#[0-9]+]]
-// NOINLINE: ret void
+// Check optnone attribute for library target compilation
+// CHECK_LIB_OPTNONE: Function Attrs:{{.*}}optnone
+// CHECK_LIB_OPTNONE: define void @_Z4swapA100_jjj(ptr noundef byval([100 x i32]) align 4 %Buf, i32 noundef %ix1, i32 noundef %ix2) [[ExtAttr:\#[0-9]+]]
+
+// Check alwaysinline attribute for non-entry functions of compute target compilation
+// CHECK_CS_OPTNONE: Function Attrs: alwaysinline
+// CHECK_CS_OPTNONE: define void @_Z4swapA100_jjj(ptr noundef byval([100 x i32]) align 4 %Buf, i32 noundef %ix1, i32 noundef %ix2) [[ExtAttr:\#[0-9]+]]
+
+// Check alwaysinline attribute for opt compilation to library target
+// CHECK_OPT: Function Attrs: alwaysinline
+// CHECK_OPT: define void @_Z4swapA100_jjj(ptr noundef byval([100 x i32]) align 4 captures(none) %Buf, i32 noundef %ix1, i32 noundef %ix2) {{[a-z_ ]*}} [[SwapOptAttr:\#[0-9]+]]
+
+// CHECK: ret void
+
 // Swap the values of Buf at indices ix1 and ix2
 void swap(unsigned Buf[MAX], unsigned ix1, unsigned ix2) {
   float tmp = Buf[ix1];
@@ -24,9 +33,20 @@ void swap(unsigned Buf[MAX], unsigned ix1, unsigned ix2) {
   Buf[ix2] = tmp;
 }
 
-// NOINLINE: Function Attrs: alwaysinline
-// NOINLINE: define void @_Z10BubbleSortA100_jj(ptr noundef byval([100 x i32]) align 4 %Buf, i32 noundef %size) [[IntAttr]]
-// NOINLINE: ret void
+// Check optnone attribute for library target compilation
+// CHECK_LIB_OPTNONE: Function Attrs:{{.*}}optnone
+// CHECK_LIB_OPTNONE: define void @_Z10BubbleSortA100_jj(ptr noundef byval([100 x i32]) align 4 %Buf, i32 noundef %size) [[ExtAttr]]
+
+// Check alwaysinline attribute for non-entry functions of compute target compilation
+// CHECK_CS_OPTNONE: Function Attrs: alwaysinline
+// CHECK_CS_OPTNONE: define void @_Z10BubbleSortA100_jj(ptr noundef byval([100 x i32]) align 4 %Buf, i32 noundef %size) [[ExtAttr]]
+
+// Check alwaysinline attribute for opt compilation to library target
+// CHECK_OPT: Function Attrs: alwaysinline
+// CHECK_OPT: define void @_Z10BubbleSortA100_jj(ptr noundef readonly byval([100 x i32]) align 4 captures(none) %Buf, i32 noundef %size) {{[a-z_ ]*}} [[BubOptAttr:\#[0-9]+]]
+
+// CHECK: ret void
+
 // Inefficiently sort Buf in place
 void BubbleSort(unsigned Buf[MAX], unsigned size) {
   bool swapped = true;
@@ -41,12 +61,22 @@ void BubbleSort(unsigned Buf[MAX], unsigned size) {
   }
 }
 
-// Note ExtAttr is the inlined export set of attribs
-// CHECK: Function Attrs: alwaysinline
-// CHECK: define noundef i32 @_Z11RemoveDupesA100_jj(ptr {{[a-z_ ]*}}noundef byval([100 x i32]) align 4 {{.*}}%Buf, i32 noundef %size) {{[a-z_ ]*}}[[ExtAttr:\#[0-9]+]]
-// CHECK: ret i32
+// Check optnone attribute for library target compilation of exported function
+// CHECK_LIB_OPTNONE: Function Attrs:{{.*}}optnone
+// CHECK_LIB_OPTNONE: define noundef i32 @_Z11RemoveDupesA100_jj(ptr {{[a-z_ ]*}}noundef byval([100 x i32]) align 4 {{.*}}%Buf, i32 noundef %size) [[ExportAttr:\#[0-9]+]]
 // Sort Buf and remove any duplicate values
 // returns the number of values left
+
+// Check alwaysinline attribute for exported function of compute target compilation
+// CHECK_CS_OPTNONE: Function Attrs: alwaysinline
+// CHECK_CS_OPTNONE: define noundef i32 @_Z11RemoveDupesA100_jj(ptr {{[a-z_ ]*}}noundef byval([100 x i32]) align 4 {{.*}}%Buf, i32 noundef %size) [[ExportAttr:\#[0-9]+]]
+
+// Check alwaysinline attribute for exported function of library target compilation
+// CHECK_OPT: Function Attrs: alwaysinline
+// CHECK_OPT: define noundef i32 @_Z11RemoveDupesA100_jj(ptr noundef byval([100 x i32]) align 4 captures(none) %Buf, i32 noundef %size) {{[a-z_ ]*}} [[RemOptAttr:\#[0-9]+]]
+
+// CHECK: ret i32
+
 export
 unsigned RemoveDupes(unsigned Buf[MAX], unsigned size) {
   BubbleSort(Buf, size);
@@ -63,19 +93,36 @@ unsigned RemoveDupes(unsigned Buf[MAX], unsigned size) {
 
 RWBuffer<unsigned> Indices;
 
-// The mangled version of main only remains without inlining
-// because it has internal linkage from the start
-// Note main functions get the norecurse attrib, which IntAttr reflects
-// NOINLINE: Function Attrs: alwaysinline
-// NOINLINE: define internal void @_Z4mainj(i32 noundef %GI) [[IntAttr]]
-// NOINLINE: ret void
+// CHECK_LIB_OPTNONE: Function Attrs:{{.*}}optnone
+// Internal function attributes are the same as those of source function's
+// CHECK_LIB_OPTNONE: define internal void @_Z4mainj(i32 noundef %GI) [[ExtAttr]]
+// CHECK_LIB_OPTNONE: ret void
+
+// CHECK_CS_OPTNONE: Function Attrs:{{.*}}optnone
+// Internal function attributes are different from those of source function's
+// CHECK_CS_OPTNONE: define internal void @_Z4mainj(i32 noundef %GI) [[IntAttr:\#[...
[truncated]

bharadwajy · 2025-02-06T01:34:38Z

Need to verify a couple more function attribute combinations. Changed it to draft mode till that is done.

Please hold off reviews.

When optimization is disabled, set optnone attribute - for all module functions when targetting Library shaders - only for entry function when targetting non-Library shaders Update tests in accordance with the change.

bharadwajy · 2025-02-06T17:24:06Z

Need to verify a couple more function attribute combinations. Changed it to draft mode till that is done.

Please hold off reviews.

PR ready for review. Thanks!

bogner · 2025-02-06T18:22:39Z

clang/lib/CodeGen/CGHLSLRuntime.cpp

@@ -345,6 +345,9 @@ void clang::CodeGen::CGHLSLRuntime::setHLSLEntryAttributes(
                WaveSizeAttr->getPreferred());
    Fn->addFnAttr(WaveSizeKindStr, WaveSizeStr);
  }
+  if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
+    Fn->addFnAttr(llvm::Attribute::OptimizeNone);
+  }
  Fn->addFnAttr(llvm::Attribute::NoInline);


Given that these already have "noinline", I'm surprised that the logic in "SetLLVMFunctionAttributesForDefinition" doesn't already put optnone on these functions. Is something undoing this later?

Given that these already have "noinline", I'm surprised that the logic in "SetLLVMFunctionAttributesForDefinition" doesn't already put optnone on these functions. Is something undoing this later?

The entry function that is created and whose attribute is set to noinline in this function is different from that SetLLVMFunctionAttributesForDefinition() looks at.

GenerateCode(GlobalFnDecl, MangledFn, ...) calls StartFunction(GlobalFnDecl, ResTy, MangledFn, ...) which in turn calls emitEntryFunction(FnDecl, MangledFn). emitEntryFunction(FnDecl, MangledFn, ...) constructs a new entry function EntryFn, sets linkage of MangledFn to be internal to arrange it to be inlined in EntryFn etc., and calls setHLSLEntryAttributes(FnDecl, EntryFn) to set attributes of EntryFn.

SetLLVMFunctionAttributesForDefinition(...) sets attributes of MangledFn. So the logic in that function checks attributes for MangledFn and not for the created EntryFn.

Hence setting optnone attribute in setHLSLEntryAttributes(FnDecl, EntryFn) of EntryFn at the time of its set up seemed appropriate - if optimizations are disabled.

Ok. I think a comment to the effect of "We need to manually set attributes here instead of relying on SetLLVMFunctionAttributesForDefinition to pick them up since these functions are injected by the compiler and won't go through the normal flow" (please reword as necessary to be accurate...) would be a good idea here.

Ok. I think a comment to the effect of "We need to manually set attributes here instead of relying on SetLLVMFunctionAttributesForDefinition to pick them up since these functions are injected by the compiler and won't go through the normal flow" (please reword as necessary to be accurate...) would be a good idea here.

Comment added. Thanks!

bogner · 2025-02-06T18:23:45Z

clang/lib/CodeGen/CGHLSLRuntime.cpp

+  llvm::Triple T(Fn->getParent()->getTargetTriple());
+  if (T.getEnvironment() == llvm::Triple::EnvironmentType::Library) {
+    if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
+      Fn->addFnAttr(llvm::Attribute::OptimizeNone);
+      Fn->addFnAttr(llvm::Attribute::NoInline);
+    }
+  }


Do we want to do this on all functions in a library or just entry points and exported functions? In any case, it really would be preferable if "SetLLVMFunctionAttributesForDefinition" did the right thing (whatever that may be) rather than us needing to duplicate that logic here...

Do we want to do this on all functions in a library or just entry points and exported functions? In any case, it really would be preferable if "SetLLVMFunctionAttributesForDefinition" did the right thing (whatever that may be) rather than us needing to duplicate that logic here...

OK. It would be sufficient to set the optnone attribute just for entry functions of both non-library shaders and library shaders since all shaders will have one or more (respectively) entry functions. The shader flag DisableOptimizations can be set based on the presence of this attribute on entry function(s).

Deleted this change.

The consequences and utility in the later passes of setting optnone attribute for exported library functions when optimizatons are disabled is not very clear to me, yet. I'd like to propose any change, if needed, be done in a follow-on PR.

shader as optnone if optimization is disabled. Update corresponding test changes

bogner

This looks reasonable to me. It would be good to get some feedback from @pow2clk and @llvm-beanz since they've done a bunch of the work in this area.

bogner · 2025-02-10T21:35:49Z

clang/lib/CodeGen/CGHLSLRuntime.cpp

@@ -345,6 +345,9 @@ void clang::CodeGen::CGHLSLRuntime::setHLSLEntryAttributes(
                WaveSizeAttr->getPreferred());
    Fn->addFnAttr(WaveSizeKindStr, WaveSizeStr);
  }
+  if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
+    Fn->addFnAttr(llvm::Attribute::OptimizeNone);
+  }
  Fn->addFnAttr(llvm::Attribute::NoInline);


Ok. I think a comment to the effect of "We need to manually set attributes here instead of relying on SetLLVMFunctionAttributesForDefinition to pick them up since these functions are injected by the compiler and won't go through the normal flow" (please reword as necessary to be accurate...) would be a good idea here.

llvm-beanz

One nit, otherwise LGTM.

llvm-beanz · 2025-02-11T16:10:02Z

clang/lib/CodeGen/CGHLSLRuntime.cpp

+  if (CGM.getCodeGenOpts().OptimizationLevel == 0) {
+    Fn->addFnAttr(llvm::Attribute::OptimizeNone);
+  }


nit: https://llvm.org/docs/CodingStandards.html#don-t-use-braces-on-simple-single-statement-bodies-of-if-else-loop-statements

Suggested change

if (CGM.getCodeGenOpts().OptimizationLevel == 0) {

Fn->addFnAttr(llvm::Attribute::OptimizeNone);

}

if (CGM.getCodeGenOpts().OptimizationLevel == 0)

Fn->addFnAttr(llvm::Attribute::OptimizeNone);

When optimization is disabled, set `optnone` attribute all module entry functions. Updated test in accordance with the change. Closes llvm#124796

bharadwajy requested a review from bogner February 5, 2025 21:31

llvmbot added clang Clang issues not falling into any other category clang:codegen IR generation bugs: mangling, exceptions, etc. HLSL HLSL Language Support labels Feb 5, 2025

bharadwajy marked this pull request as draft February 6, 2025 01:31

[HLSL] Set function optnone attribute appropriately

63a728d

When optimization is disabled, set optnone attribute - for all module functions when targetting Library shaders - only for entry function when targetting non-Library shaders Update tests in accordance with the change.

bharadwajy force-pushed the func-attr-disable-opt branch from f04a746 to 63a728d Compare February 6, 2025 17:18

bharadwajy marked this pull request as ready for review February 6, 2025 17:19

bharadwajy requested a review from pow2clk February 6, 2025 17:24

bogner reviewed Feb 6, 2025

View reviewed changes

[HLSL] Delete the change that sets non-entry functions of a library

00897b8

shader as optnone if optimization is disabled. Update corresponding test changes

bharadwajy requested a review from bogner February 10, 2025 16:02

bogner approved these changes Feb 10, 2025

View reviewed changes

bharadwajy requested a review from llvm-beanz February 10, 2025 21:42

bharadwajy mentioned this pull request Feb 10, 2025

[DirectX] Set Shader Flag DisableOptimizations. #123136

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54b1e87

llvm-beanz approved these changes Feb 11, 2025

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Delete braces around simple single-statement body of if statement

37bcc29

bharadwajy merged commit b92bab3 into llvm:main Feb 11, 2025
6 of 8 checks passed

bharadwajy mentioned this pull request Feb 11, 2025

[HLSL] Figure out OptimizeNone attribute and always inline interactions #126816

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damyanp moved this from Needs Review to Closed in HLSL Support Apr 22, 2025

damyanp removed this from HLSL Support Jun 25, 2025

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