[HLSL] Don't use CreateRuntimeFunction for intrinsics

[nikic]

HLSL uses CreateRuntimeFunction for three intrinsics. This is pretty unusual thing to do, and doesn't match what the rest of the file does.

I suspect this might be because these are convergent calls, but the intrinsics themselves are already marked convergent, so it's not necessary for clang to manually add the attribute.

This does lose the spir_func CC on the intrinsic declaration, but again, CC should not be relevant to intrinsics at all.

[llvmbot]

@llvm/pr-subscribers-hlsl

@llvm/pr-subscribers-clang-codegen

Author: Nikita Popov (nikic)

Changes

HLSL uses CreateRuntimeFunction for two intrinsics. This is pretty unusual thing to do, and doesn't match what the rest of the file does.

I suspect this might be because these are convergent calls, but the intrinsics themselves are already marked convergent, so it's not necessary for clang to manually add the attribute.

This does lose the spir_func CC on the intrinsic declaration, but again, CC should not be relevant to intrinsics at all.

---

Full diff: https://github.com/llvm/llvm-project/pull/145334.diff

3 Files Affected:

• (modified) clang/lib/CodeGen/CGHLSLBuiltins.cpp (+4-16)
• (modified) clang/test/CodeGenHLSL/builtins/WaveActiveMax.hlsl (+3-3)
• (modified) clang/test/CodeGenHLSL/builtins/WaveActiveSum.hlsl (+3-3)

diff --git a/clang/lib/CodeGen/CGHLSLBuiltins.cpp b/clang/lib/CodeGen/CGHLSLBuiltins.cpp
index 2a60a0909c93e..5074a915f2817 100644
--- a/clang/lib/CodeGen/CGHLSLBuiltins.cpp
+++ b/clang/lib/CodeGen/CGHLSLBuiltins.cpp
@@ -676,35 +676,23 @@ Value *CodeGenFunction::EmitHLSLBuiltinExpr(unsigned BuiltinID,
   case Builtin::BI__builtin_hlsl_wave_active_sum: {
     // Due to the use of variadic arguments, explicitly retreive argument
     Value *OpExpr = EmitScalarExpr(E->getArg(0));
-    llvm::FunctionType *FT = llvm::FunctionType::get(
-        OpExpr->getType(), ArrayRef{OpExpr->getType()}, false);
     Intrinsic::ID IID = getWaveActiveSumIntrinsic(
         getTarget().getTriple().getArch(), CGM.getHLSLRuntime(),
         E->getArg(0)->getType());
 
-    // Get overloaded name
-    std::string Name =
-        Intrinsic::getName(IID, ArrayRef{OpExpr->getType()}, &CGM.getModule());
-    return EmitRuntimeCall(CGM.CreateRuntimeFunction(FT, Name, {},
-                                                     /*Local=*/false,
-                                                     /*AssumeConvergent=*/true),
+    return EmitRuntimeCall(Intrinsic::getOrInsertDeclaration(
+                               &CGM.getModule(), IID, {OpExpr->getType()}),
                            ArrayRef{OpExpr}, "hlsl.wave.active.sum");
   }
   case Builtin::BI__builtin_hlsl_wave_active_max: {
     // Due to the use of variadic arguments, explicitly retreive argument
     Value *OpExpr = EmitScalarExpr(E->getArg(0));
-    llvm::FunctionType *FT = llvm::FunctionType::get(
-        OpExpr->getType(), ArrayRef{OpExpr->getType()}, false);
     Intrinsic::ID IID = getWaveActiveMaxIntrinsic(
         getTarget().getTriple().getArch(), CGM.getHLSLRuntime(),
         E->getArg(0)->getType());
 
-    // Get overloaded name
-    std::string Name =
-        Intrinsic::getName(IID, ArrayRef{OpExpr->getType()}, &CGM.getModule());
-    return EmitRuntimeCall(CGM.CreateRuntimeFunction(FT, Name, {},
-                                                     /*Local=*/false,
-                                                     /*AssumeConvergent=*/true),
+    return EmitRuntimeCall(Intrinsic::getOrInsertDeclaration(
+                               &CGM.getModule(), IID, {OpExpr->getType()}),
                            ArrayRef{OpExpr}, "hlsl.wave.active.max");
   }
   case Builtin::BI__builtin_hlsl_wave_get_lane_index: {
diff --git a/clang/test/CodeGenHLSL/builtins/WaveActiveMax.hlsl b/clang/test/CodeGenHLSL/builtins/WaveActiveMax.hlsl
index 7891cfc1989af..be05a17cc3692 100644
--- a/clang/test/CodeGenHLSL/builtins/WaveActiveMax.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/WaveActiveMax.hlsl
@@ -16,7 +16,7 @@ int test_int(int expr) {
 }
 
 // CHECK-DXIL: declare [[TY]] @llvm.dx.wave.reduce.max.i32([[TY]]) #[[#attr:]]
-// CHECK-SPIRV: declare spir_func [[TY]] @llvm.spv.wave.reduce.max.i32([[TY]]) #[[#attr:]]
+// CHECK-SPIRV: declare [[TY]] @llvm.spv.wave.reduce.max.i32([[TY]]) #[[#attr:]]
 
 // CHECK-LABEL: test_uint64_t
 uint64_t test_uint64_t(uint64_t expr) {
@@ -27,7 +27,7 @@ uint64_t test_uint64_t(uint64_t expr) {
 }
 
 // CHECK-DXIL: declare [[TY]] @llvm.dx.wave.reduce.umax.i64([[TY]]) #[[#attr:]]
-// CHECK-SPIRV: declare spir_func [[TY]] @llvm.spv.wave.reduce.umax.i64([[TY]]) #[[#attr:]]
+// CHECK-SPIRV: declare [[TY]] @llvm.spv.wave.reduce.umax.i64([[TY]]) #[[#attr:]]
 
 // Test basic lowering to runtime function call with array and float value.
 
@@ -40,7 +40,7 @@ float4 test_floatv4(float4 expr) {
 }
 
 // CHECK-DXIL: declare [[TY1]] @llvm.dx.wave.reduce.max.v4f32([[TY1]]) #[[#attr]]
-// CHECK-SPIRV: declare spir_func [[TY1]] @llvm.spv.wave.reduce.max.v4f32([[TY1]]) #[[#attr]]
+// CHECK-SPIRV: declare [[TY1]] @llvm.spv.wave.reduce.max.v4f32([[TY1]]) #[[#attr]]
 
 // CHECK: attributes #[[#attr]] = {{{.*}} convergent {{.*}}}
 
diff --git a/clang/test/CodeGenHLSL/builtins/WaveActiveSum.hlsl b/clang/test/CodeGenHLSL/builtins/WaveActiveSum.hlsl
index 4bf423ccc1b82..1fc93c62c8db0 100644
--- a/clang/test/CodeGenHLSL/builtins/WaveActiveSum.hlsl
+++ b/clang/test/CodeGenHLSL/builtins/WaveActiveSum.hlsl
@@ -16,7 +16,7 @@ int test_int(int expr) {
 }
 
 // CHECK-DXIL: declare [[TY]] @llvm.dx.wave.reduce.sum.i32([[TY]]) #[[#attr:]]
-// CHECK-SPIRV: declare spir_func [[TY]] @llvm.spv.wave.reduce.sum.i32([[TY]]) #[[#attr:]]
+// CHECK-SPIRV: declare [[TY]] @llvm.spv.wave.reduce.sum.i32([[TY]]) #[[#attr:]]
 
 // CHECK-LABEL: test_uint64_t
 uint64_t test_uint64_t(uint64_t expr) {
@@ -27,7 +27,7 @@ uint64_t test_uint64_t(uint64_t expr) {
 }
 
 // CHECK-DXIL: declare [[TY]] @llvm.dx.wave.reduce.usum.i64([[TY]]) #[[#attr:]]
-// CHECK-SPIRV: declare spir_func [[TY]] @llvm.spv.wave.reduce.sum.i64([[TY]]) #[[#attr:]]
+// CHECK-SPIRV: declare [[TY]] @llvm.spv.wave.reduce.sum.i64([[TY]]) #[[#attr:]]
 
 // Test basic lowering to runtime function call with array and float value.
 
@@ -40,6 +40,6 @@ float4 test_floatv4(float4 expr) {
 }
 
 // CHECK-DXIL: declare [[TY1]] @llvm.dx.wave.reduce.sum.v4f32([[TY1]]) #[[#attr]]
-// CHECK-SPIRV: declare spir_func [[TY1]] @llvm.spv.wave.reduce.sum.v4f32([[TY1]]) #[[#attr]]
+// CHECK-SPIRV: declare [[TY1]] @llvm.spv.wave.reduce.sum.v4f32([[TY1]]) #[[#attr]]
 
 // CHECK: attributes #[[#attr]] = {{{.*}} convergent {{.*}}}

[farzonl]

This is correct. @Keenuts did EmitRuntimeCall(Intrinsic::getOrInsertDeclaration( in https://github.com/llvm/llvm-project/pull/143127/files Thats what we expect to use for these convergence intrinsics.

Looks like this was just an accident introduced in this pr: https://github.com/llvm/llvm-project/pull/118580/files#diff-202c36399fe94363f22692e534129341972137a24721c385b1f1f05fb239dd79R19523 and then the patttern may have been copied by others.

[farzonl]

LGTM