Hlsl asuint16 function #132315

metkarpoonam · 2025-03-21T00:40:06Z

Implemented the asuint16 function and added test cases for codegen, Sema, and SPIR-V backend.
fixes #99185

llvmbot · 2025-03-21T00:40:39Z

@llvm/pr-subscribers-clang
@llvm/pr-subscribers-backend-x86
@llvm/pr-subscribers-hlsl

@llvm/pr-subscribers-backend-spir-v

Author: None (metkarpoonam)

Changes

Implemented the asuint16 function and added test cases for codegen, Sema, and SPIR-V backend.
fixes #99185

Full diff: https://github.com/llvm/llvm-project/pull/132315.diff

4 Files Affected:

(modified) clang/lib/Headers/hlsl/hlsl_intrinsics.h (+28)
(added) clang/test/CodeGenHLSL/builtins/asuint16.hlsl (+60)
(added) clang/test/SemaHLSL/BuiltIns/asuint16-errors.hlsl (+51)
(added) llvm/test/CodeGen/SPIRV/hlsl-intrinsics/asuint16.ll (+37)

diff --git a/clang/lib/Headers/hlsl/hlsl_intrinsics.h b/clang/lib/Headers/hlsl/hlsl_intrinsics.h
index a48a8e998a015..70cbed851f0f0 100644
--- a/clang/lib/Headers/hlsl/hlsl_intrinsics.h
+++ b/clang/lib/Headers/hlsl/hlsl_intrinsics.h
@@ -80,6 +80,34 @@ void asuint(double3, out uint3, out uint3);
 _HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_splitdouble)
 void asuint(double4, out uint4, out uint4);
 
+//===----------------------------------------------------------------------===//
+// asuint16 builtins
+//===----------------------------------------------------------------------===//
+
+/// \fn uint16_t asuint16(T X)
+/// \brief Interprets the bit pattern of \a X as an 16-bit unsigned integer.
+/// \param X The input value.
+#ifdef __HLSL_ENABLE_16_BIT
+
+template <typename T, int N>
+constexpr __detail::enable_if_t<__detail::is_same<int16_t, T>::value ||
+                                    __detail::is_same<uint16_t, T>::value ||
+                                    __detail::is_same<half, T>::value,
+                                vector<uint16_t, N>>
+asuint16(vector<T, N> V) {
+  return __detail::bit_cast<uint16_t, T, N>(V);
+}
+
+template <typename T>
+constexpr __detail::enable_if_t<__detail::is_same<int16_t, T>::value ||
+                                    __detail::is_same<uint16_t, T>::value ||
+                                    __detail::is_same<half, T>::value,
+                                uint16_t>
+asuint16(T F) {
+  return __detail::bit_cast<uint16_t, T>(F);
+}
+#endif
+
 //===----------------------------------------------------------------------===//
 // distance builtins
 //===----------------------------------------------------------------------===//
diff --git a/clang/test/CodeGenHLSL/builtins/asuint16.hlsl b/clang/test/CodeGenHLSL/builtins/asuint16.hlsl
new file mode 100644
index 0000000000000..0efda5f9331a9
--- /dev/null
+++ b/clang/test/CodeGenHLSL/builtins/asuint16.hlsl
@@ -0,0 +1,60 @@
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple dxil-pc-shadermodel6.2-library %s -fnative-half-type -emit-llvm -O1 -o - | FileCheck %s
+
+//CHECK-LABEL: define {{.*}}test_ints
+//CHECK-SAME: {{.*}}(i16 {{.*}} [[VAL:%.*]]){{.*}}
+// CHECK-NOT: bitcast
+//CHECK: entry:
+// CHECK: ret i16 [[VAL]]
+uint16_t test_int(int16_t p0)
+{
+    return asuint16(p0);
+}
+
+//CHECK-LABEL: define {{.*}}test_uint
+//CHECK-SAME: {{.*}}(i16 {{.*}} [[VAL:%.*]]){{.*}}
+//CHECK-NOT: bitcast
+//CHECK: entry:
+//CHECK-NEXT: ret i16 [[VAL]]
+uint16_t test_uint(uint16_t p0)
+{
+    return asuint16(p0);
+}
+
+//CHECK-LABEL: define {{.*}}test_half
+//CHECK-SAME: {{.*}}(half {{.*}} [[VAL:%.*]]){{.*}}
+//CHECK: [[RES:%.*]] = bitcast half [[VAL]] to i16
+//CHECK-NEXT: ret i16 [[RES]]
+uint16_t test_half(half p0)
+{
+    return asuint16(p0);
+}
+
+//CHECK-LABEL: define {{.*}}test_vector_int
+//CHECK-SAME: {{.*}}(<4 x i16> {{.*}} [[VAL:%.*]]){{.*}}
+//CHECK-NOT: bitcast
+//CHECK: entry:
+//CHECK-NEXT: ret <4 x i16> [[VAL]]
+uint16_t4 test_vector_int(int16_t4 p0)
+{
+    return asuint16(p0);
+}
+
+//CHECK-LABEL: define {{.*}}test_vector_uint
+//CHECK-SAME: {{.*}}(<4 x i16> {{.*}} [[VAL:%.*]]){{.*}}
+//CHECK-NOT: bitcast
+//CHECK: entry:
+//CHECK-NEXT: ret <4 x i16> [[VAL]]
+uint16_t4 test_vector_uint(uint16_t4 p0)
+{
+    return asuint16(p0);
+}
+
+//CHECK-LABEL: define {{.*}}fn
+//CHECK-SAME: {{.*}}(<4 x half> {{.*}} [[VAL:%.*]]){{.*}}
+//CHECK: [[RES:%.*]] = bitcast <4 x half> [[VAL]] to <4 x i16>
+//CHECK-NEXT: ret <4 x i16> [[RES]]
+uint16_t4 fn(half4 p1)
+{
+    return asuint16(p1);
+}
+
diff --git a/clang/test/SemaHLSL/BuiltIns/asuint16-errors.hlsl b/clang/test/SemaHLSL/BuiltIns/asuint16-errors.hlsl
new file mode 100644
index 0000000000000..364eb828d81f4
--- /dev/null
+++ b/clang/test/SemaHLSL/BuiltIns/asuint16-errors.hlsl
@@ -0,0 +1,51 @@
+// RUN: %clang_cc1 -finclude-default-header -triple dxil-pc-shadermodel6.2-library %s -fnative-half-type -verify
+
+uint16_t test_asuint16_less_argument()
+{
+    return asuint16();
+  // expected-error@-1 {{no matching function for call to 'asuint16'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not viable: requires single argument 'V', but no arguments were provided}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not viable: requires single argument 'F', but no arguments were provided}}
+
+}
+
+int16_t4 test_asuint16_too_many_arg(uint16_t p0, uint16_t p1)
+{
+    return asuint16(p0, p1);
+  // expected-error@-1 {{no matching function for call to 'asuint16'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not viable: requires single argument 'V', but 2 arguments were provided}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not viable: requires single argument 'F', but 2 arguments were provided}}
+
+}
+
+int16_t test_asuint16_int(int p1)
+{
+    return asuint16(p1);
+  // expected-error@-1 {{no matching function for call to 'asuint16'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: could not match 'vector<T, N>' against 'int'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: substitution failure [with T = int]: no type named 'Type'}}
+}
+
+int16_t test_asuint16_float(float p1)
+{
+    return asuint16(p1);
+  // expected-error@-1 {{no matching function for call to 'asuint16'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: could not match 'vector<T, N>' against 'float'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: substitution failure [with T = float]: no type named 'Type'}}
+}
+
+int16_t4 test_asuint16_vector_int(int4 p1)
+{
+    return asuint16(p1);
+  // expected-error@-1 {{no matching function for call to 'asuint16'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: substitution failure [with T = int, N = 4]: no type named 'Type'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: substitution failure [with T = int4]: no type named 'Type'}}
+}
+
+int16_t4 test_asuint16_vector_float(float4 p1)
+{
+    return asuint16(p1);
+  // expected-error@-1 {{no matching function for call to 'asuint16'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: substitution failure [with T = float, N = 4]: no type named 'Type'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: substitution failure [with T = float4]: no type named 'Type'}}
+}
diff --git a/llvm/test/CodeGen/SPIRV/hlsl-intrinsics/asuint16.ll b/llvm/test/CodeGen/SPIRV/hlsl-intrinsics/asuint16.ll
new file mode 100644
index 0000000000000..3c9e6733c1805
--- /dev/null
+++ b/llvm/test/CodeGen/SPIRV/hlsl-intrinsics/asuint16.ll
@@ -0,0 +1,37 @@
+; RUN: llc -O0 -verify-machineinstrs -mtriple=spirv-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+; CHECK-DAG: %[[#half:]] = OpTypeFloat 16
+; CHECK-DAG: %[[#uint_16:]] = OpTypeInt 16 0
+; CHECK-DAG: %[[#v4uint_16:]] = OpTypeVector %[[#uint_16]] 4
+; CHECK-DAG: %[[#v4half:]] = OpTypeVector %[[#half]] 4
+
+define i16 @test_half(half nofpclass(nan inf) %p0) {
+entry:
+  %0 = bitcast half %p0 to i16
+  ret i16 %0
+
+ ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#half]]
+ ; CHECK: %[[#bit_cast:]] = OpBitcast %[[#uint_16]] %[[#arg0]]
+ ; CHECK: OpReturnValue %[[#bit_cast]]
+}
+
+define noundef <4 x i16> @test_vector_half(<4 x half> nofpclass(nan inf) %p1) {
+entry:
+  %0 = bitcast <4 x half> %p1 to <4 x i16>
+  ret <4 x i16> %0
+
+ ; CHECK: %[[#arg0:]] = OpFunctionParameter %[[#v4half]]
+ ; CHECK: %[[#bit_cast:]] = OpBitcast %[[#v4uint_16]] %[[#arg0]]
+ ; CHECK: OpReturnValue %[[#bit_cast]]
+}
+
+attributes #0 = { alwaysinline mustprogress nofree norecurse nosync nounwind willreturn memory(none) "approx-func-fp-math"="true" "no-infs-fp-math"="true" "no-nans-fp-math"="true" "no-signed-zeros-fp-math"="true" "no-trapping-math"="true" "stack-protector-buffer-size"="8" }
+
+!llvm.module.flags = !{!0}
+!dx.valver = !{!1}
+!llvm.ident = !{!2}
+
+!0 = !{i32 1, !"wchar_size", i32 4}
+!1 = !{i32 1, i32 8}
+!2 = !{!"clang version 21.0.0git (https://github.com/llvm/llvm-project.git 8037234c865d98219b54a70d9d63aee1d1f2be1c)"}

farzonl · 2025-03-21T03:26:55Z

llvm/test/CodeGen/SPIRV/hlsl-intrinsics/asuint16.ll

+; RUN: llc -O0 -verify-machineinstrs -mtriple=spirv-unknown-unknown %s -o - | FileCheck %s
+; RUN: %if spirv-tools %{ llc -O0 -mtriple=spirv-unknown-unknown %s -o - -filetype=obj | spirv-val %}
+
+; CHECK-DAG: %[[#half:]] = OpTypeFloat 16


delete this file. the tests you have in the asint16 pr are sufficient to for testing OpBitcast works for both scalars and vectors.

I've removed the asuint16.ll as suggested.

farzonl · 2025-03-21T03:30:08Z

clang/test/CodeGenHLSL/builtins/asuint16.hlsl

+
+//CHECK-LABEL: define {{.*}}test_ints
+//CHECK-SAME: {{.*}}(i16 {{.*}} [[VAL:%.*]]){{.*}}
+// CHECK-NOT: bitcast


all the check lines in the file should line up remove space here and line 7

I've removed the spaces as suggested.

farzonl · 2025-03-21T03:31:39Z

clang/lib/Headers/hlsl/hlsl_intrinsics.h

+#ifdef __HLSL_ENABLE_16_BIT
+
+template <typename T, int N>
+constexpr __detail::enable_if_t<__detail::is_same<int16_t, T>::value ||


you need to add the Shader Model 6.2 availability macro to these two functions.

Added suggested shader model macro.

github-actions · 2025-03-21T04:12:23Z

✅ With the latest revision this PR passed the C/C++ code formatter.

V-FEXrt

LGTM but I'll let Farzon approve

V-FEXrt · 2025-03-21T16:54:42Z

clang/test/SemaHLSL/BuiltIns/asuint16-errors.hlsl

+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: could not match 'vector<T, N>' against 'int'}}
+  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: substitution failure [with T = int]: no type named 'Type'}}


Probably not an actionable item unless @farzonl has any ideas

The notes here feel quite unhelpful from a user perspective. I'm guessing the error is that int doesn't fit in int16_t but if I was a user and I saw this error then I'd be extremely confusing by what's actually wrong. That said the actual error at least points at the function and tells you it's the wrong overload so maybe not

Since this is a language overload resolution rule and not one we defined in sema there is not much we can do in this PR. Atleast nothing that woudn't be considered scope creep. Worth talk with Chris about though and see if there is something we can change.

farzonl

LGTM

metkarpoonam added 6 commits March 20, 2025 17:36

Add asuint16 intrinsic and codegen test

6ce249d

Update the uint16 function call and add space in uint16.hlsl

a912b35

Add sema tests to asuint16-errors.hlsl

8cabaa4

Update asuint16.ll

326b4d9

WIP on asuint16.hlsl

fb46c7e

Update codegen asuint16.hlsl test

0257f04

llvmbot added clang Clang issues not falling into any other category backend:X86 clang:headers Headers provided by Clang, e.g. for intrinsics HLSL HLSL Language Support backend:SPIR-V labels Mar 21, 2025

github-project-automation bot added this to HLSL Support Mar 21, 2025

metkarpoonam added 2 commits March 20, 2025 17:53

Add new line to the asuint16-errors.hlsl

7eaedca

Add new line to the asuint16-errors.hlsl and asuint16.ll

b1d0f39

farzonl reviewed Mar 21, 2025

View reviewed changes

Address review comments

4c0e763

Apply clang-format on hlsl_intrinsic.h

3ff65ee

V-FEXrt reviewed Mar 21, 2025

View reviewed changes

farzonl approved these changes Mar 21, 2025

View reviewed changes

farzonl merged commit 5ecbf46 into llvm:main Mar 21, 2025
11 checks passed

damyanp moved this to Closed in HLSL Support Apr 25, 2025

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Hlsl asuint16 function #132315

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		// expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: could not match 'vector<T, N>' against 'int'}}
		// expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: substitution failure [with T = int]: no type named 'Type'}}

Hlsl asuint16 function #132315

Hlsl asuint16 function #132315

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