From 86fc50c5092fbccf6072dcf7bbdfafb8915f02c8 Mon Sep 17 00:00:00 2001
From: Yong He <yonghe@outlook.com>
Date: Wed, 8 Mar 2023 21:52:34 -0800
Subject: Add support for `[PrimalSubstitute]` and `[PrimalSubstituteOf]`.
 (#2691)

* Add support for `[PrimalSubstitute]` and `[PrimalSubstituteOf]`.

* Fix

* Fix.

* Cleanup.

---------

Co-authored-by: Yong He <yhe@nvidia.com>
---
 source/slang/diff.meta.slang | 85 ++++++--------------------------------------
 1 file changed, 11 insertions(+), 74 deletions(-)

(limited to 'source/slang/diff.meta.slang')

diff --git a/source/slang/diff.meta.slang b/source/slang/diff.meta.slang
index 54f927816..4301eda94 100644
--- a/source/slang/diff.meta.slang
+++ b/source/slang/diff.meta.slang
@@ -11,6 +11,9 @@ attribute_syntax [ForwardDerivative(function)] : ForwardDerivativeAttribute;
 __attributeTarget(FunctionDeclBase)
 attribute_syntax [BackwardDerivative(function)] : BackwardDerivativeAttribute;
 
+__attributeTarget(FunctionDeclBase)
+attribute_syntax [PrimalSubstitute(function)] : PrimalSubstituteAttribute;
+
 __attributeTarget(FunctionDeclBase)
 attribute_syntax [BackwardDifferentiable] : BackwardDifferentiableAttribute;
 
@@ -20,6 +23,9 @@ attribute_syntax [ForwardDerivativeOf(function)] : ForwardDerivativeOfAttribute;
 __attributeTarget(FunctionDeclBase)
 attribute_syntax [BackwardDerivativeOf(function)] : BackwardDerivativeOfAttribute;
 
+__attributeTarget(FunctionDeclBase)
+attribute_syntax [PrimalSubstituteOf(function)] : PrimalSubstituteOfAttribute;
+
 __attributeTarget(DeclBase)
 attribute_syntax [DerivativeMember(memberName)] : DerivativeMemberAttribute;
 
@@ -1037,6 +1043,7 @@ void __d_refract(inout DifferentialPair<vector<T, N>> i, inout DifferentialPair<
 // Sine and cosine
 __generic<T : __BuiltinFloatingPointType>
 [BackwardDifferentiable]
+[PrimalSubstituteOf(sincos)]
 void __sincos_impl(T x, out T s, out T c)
 {
     s = sin(x);
@@ -1045,6 +1052,7 @@ void __sincos_impl(T x, out T s, out T c)
 
 __generic<T : __BuiltinFloatingPointType, let N : int>
 [BackwardDifferentiable]
+[PrimalSubstituteOf(sincos)]
 void __sincos_impl(vector<T, N> x, out vector<T, N> s, out vector<T, N> c)
 {
     s = sin(x);
@@ -1053,62 +1061,18 @@ void __sincos_impl(vector<T, N> x, out vector<T, N> s, out vector<T, N> c)
 
 __generic<T : __BuiltinFloatingPointType, let N : int, let M : int>
 [BackwardDifferentiable]
+[PrimalSubstituteOf(sincos)]
 void __sincos_impl(matrix<T, N, M> x, out matrix<T, N, M> s, out matrix<T, N, M> c)
 {
     s = sin(x);
     c = cos(x);
 }
 
-__generic<T: __BuiltinFloatingPointType>
-[ForwardDerivativeOf(sincos)]
-[ForceInline]
-void __d_sincos(DifferentialPair<T> x, out DifferentialPair<T> s, out DifferentialPair<T> c)
-{
-    __fwd_diff(__sincos_impl)(x, s, c);
-}
-
-__generic<T : __BuiltinFloatingPointType, let N : int>
-[ForwardDerivativeOf(sincos)]
-[ForceInline]
-void __d_sincos(DifferentialPair<vector<T, N>> x, out DifferentialPair<vector<T, N>> s, out DifferentialPair<vector<T, N>> c)
-{
-    __fwd_diff(__sincos_impl)(x, s, c);
-}
-
-__generic<T : __BuiltinFloatingPointType, let N : int, let M : int>
-[ForwardDerivativeOf(sincos)]
-[ForceInline]
-void __d_sincos(DifferentialPair<matrix<T, N, M>> x, out DifferentialPair<matrix<T, N, M>> s, out DifferentialPair<matrix<T, N, M>> c)
-{
-    __fwd_diff(__sincos_impl)(x, s, c);
-}
-
-__generic<T: __BuiltinFloatingPointType>
-[BackwardDerivativeOf(sincos)]
-[ForceInline]
-void __d_sincos(inout DifferentialPair<T> x, T.Differential dS, T.Differential dC)
-{
-    __bwd_diff(__sincos_impl)(x, dS, dC);
-}
-__generic<T: __BuiltinFloatingPointType, let N : int>
-[BackwardDerivativeOf(sincos)]
-[ForceInline]
-void __d_sincos(inout DifferentialPair<vector<T, N>> x, vector<T, N>.Differential dS, vector<T, N>.Differential dC)
-{
-    __bwd_diff(__sincos_impl)(x, dS, dC);
-}
-
-__generic<T : __BuiltinFloatingPointType, let N : int, let M : int>
-[BackwardDerivativeOf(sincos)]
-[ForceInline]
-void __d_sincos(inout DifferentialPair<matrix<T, N, M>> x, matrix<T, N, M>.Differential dS, matrix<T, N, M>.Differential dC)
-{
-    __bwd_diff(__sincos_impl)(x, dS, dC);
-}
 
 // dst (obsolete)
 __generic<T : __BuiltinFloatingPointType>
 [BackwardDifferentiable]
+[PrimalSubstituteOf(dst)]
 vector<T, 4> __dst_impl(vector<T, 4> src0, vector<T, 4> src1)
 {
     vector<T, 4> dest;
@@ -1118,25 +1082,11 @@ vector<T, 4> __dst_impl(vector<T, 4> src0, vector<T, 4> src1)
     dest.w = src1.w; ;
     return dest;
 }
-__generic<T : __BuiltinFloatingPointType>
-[ForwardDerivativeOf(dst)]
-[ForceInline]
-DifferentialPair<vector<T, 4>> __d_dst(DifferentialPair<vector<T, 4>> src0, DifferentialPair<vector<T, 4>> src1)
-{
-    return __fwd_diff(__dst_impl)(src0, src1);
-}
-__generic<T : __BuiltinFloatingPointType>
-[BackwardDerivativeOf(dst)]
-[ForceInline]
-void __d_dst(inout DifferentialPair<vector<T, 4>> src0, inout DifferentialPair<vector<T, 4>> src1, vector<T, 4>.Differential dOut)
-{
-    __bwd_diff(__dst_impl)(src0, src1, dOut);
-}
 
 // Legacy lighting function (obsolete)
-__target_intrinsic(hlsl)
 [__readNone]
 [BackwardDifferentiable]
+[PrimalSubstituteOf(lit)]
 float4 __lit_impl(float n_dot_l, float n_dot_h, float m)
 {
     let ambient = 1.0f;
@@ -1144,19 +1094,6 @@ float4 __lit_impl(float n_dot_l, float n_dot_h, float m)
     let specular = ((n_dot_l < 0.0f || n_dot_h < 0.0) ? 0.0 : pow(n_dot_h, m));
     return float4(ambient, diffuse, specular, 1.0f);
 }
-[ForwardDerivativeOf(lit)]
-[ForceInline]
-DifferentialPair<float4> __d_lit(DifferentialPair<float> n_dot_l, DifferentialPair<float> n_dot_h, DifferentialPair<float> m)
-{
-    return __fwd_diff(__lit_impl)(n_dot_l, n_dot_h, m);
-}
-[BackwardDerivativeOf(lit)]
-[ForceInline]
-void __d_lit(inout DifferentialPair<float> n_dot_l, inout DifferentialPair<float> n_dot_h, inout DifferentialPair<float> m, float4 dOut)
-{
-    __bwd_diff(__lit_impl)(n_dot_l, n_dot_h, m, dOut);
-}
-
 // Matrix determinant
 __generic<T : __BuiltinFloatingPointType, let N : int>
 [BackwardDifferentiable]
-- 
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