[HLSL] add sqrt library function

[bob80905]

Summary

This change exposes the sqrt library function for HLSL scalar types,
excluding long and long long doubles. Sqrt is supported for all scalar, vector,
and matrix types. This patch only adds a subset of scalar type support.

Long and long long double support is missing in this patch because that type
doesn't exist in HLSL.

The full documentation of the HLSL asin function is available here:
https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-sqrt

[pow2clk]

A very minor suggestion. This looks pretty straightforward.

clang/test/CodeGenHLSL/builtins/sqrt.hlsl

6

The -fnative-half-type suggests that you're readying this for when 16-bit types are available. That's fine, but in the spirit of starting as early as possible as we tend to do with these, you might want to target shadermodel6.2 instead since that's where they were introduced and sqrt is as old as HLSL 1.0 AFAIK.

[bob80905]

Shader Model target update
Change the shader model target to 6.2, because that is when fnative-half-type was introduced.

[bob80905]

rebase
rebasing review to latest origin/main.

[bob80905]

include both commits

[bob80905]

add hlslintr.h file

[bob80905]

Include previous commit

[beanz]

LGTM

[bob80905]

• add empty line to end of file sqrt.hlsl

[python3kgae]

clang/lib/Headers/hlsl/hlsl_intrinsics.h

17

This should be removed.
We're using __builtin_elementwise_abs now.

clang/lib/Headers/hlsl/hlsl_intrinsics.h

 //===----- hlsl_intrinsics.h - HLSL definitions for intrinsics ----------===//
 //
 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
 // See https://llvm.org/LICENSE.txt for license information.
 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef _HLSL_HLSL_INTRINSICS_H_
 #define _HLSL_HLSL_INTRINSICS_H_
 
 __attribute__((clang_builtin_alias(__builtin_hlsl_wave_active_count_bits))) uint
 WaveActiveCountBits(bool bBit);
 
+// abs builtins
 __attribute__((clang_builtin_alias(__builtin_abs))) int abs(int In);
 __attribute__((clang_builtin_alias(__builtin_labs))) int64_t abs(int64_t In);
 __attribute__((clang_builtin_alias(__builtin_fabsf))) float abs(float In);
 __attribute__((clang_builtin_alias(__builtin_fabs))) double abs(double In);
 
 #ifdef __HLSL_ENABLE_16_BIT
 __attribute__((clang_builtin_alias(__builtin_fabsf16))) half abs(half In);
 #endif
 
+// sqrt builtins
+__attribute__((clang_builtin_alias(__builtin_sqrt))) double sqrt(double In);
+__attribute__((clang_builtin_alias(__builtin_sqrtf))) float sqrt(float In);
+
+#ifdef __HLSL_ENABLE_16_BIT
+__attribute__((clang_builtin_alias(__builtin_sqrtf16))) half sqrt(half In);
+#endif
+
 #endif //_HLSL_HLSL_INTRINSICS_H_

clang/test/CodeGenHLSL/builtins/sqrt.hlsl

+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -x hlsl -triple \
+// RUN:   dxil-pc-shadermodel6.3-library %s -fnative-half-type \
+// RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s
+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -x hlsl -triple \
+// RUN:   dxil-pc-shadermodel6.3-library %s -emit-llvm -disable-llvm-passes \
+// RUN:   -o - | FileCheck %s --check-prefix=NO_HALF
+
+double sqrt_d(double x)
+{
+  return sqrt(x);
+}
+
+// CHECK: define noundef double @"?sqrt_d@@YANN@Z"(
+// CHECK: call double @llvm.sqrt.f64(double %0)
+
+float sqrt_f(float x)
+{
+  return sqrt(x);
+}
+
+// CHECK: define noundef float @"?sqrt_f@@YAMM@Z"(
+// CHECK: call float @llvm.sqrt.f32(float %0)
+
+half sqrt_h(half x)
+{
+  return sqrt(x);
+}
+
+// CHECK: define noundef half @"?sqrt_h@@YA$f16@$f16@@Z"(
+// CHECK: call half @llvm.sqrt.f16(half %0)
+// NO_HALF: define noundef float @"?sqrt_h@@YA$halff@$halff@@Z"(
+// NO_HALF: call float @llvm.sqrt.f32(float %0)
 No newline at end of file