From 53dd5928c35d5a5cb1f7d2a563348fd1fa87d672 Mon Sep 17 00:00:00 2001
From: kaizhangNV <149626564+kaizhangNV@users.noreply.github.com>
Date: Tue, 5 Nov 2024 07:32:49 -0600
Subject: Fixing the wrong implementation of some math intrinsic (#5491)

* Fixing the wrong implementation of some math intrinsic

Close the issue #5282

The root cause of the issue is that log10 is not supported in wgsl.
So add the implementation.

Also ldexp in wgsl doesn't support float type exponent, so fix the
implementation of the intrinsic.

* re-enable the tests
---
 source/slang/hlsl.meta.slang | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

(limited to 'source')

diff --git a/source/slang/hlsl.meta.slang b/source/slang/hlsl.meta.slang
index 525b666ab..6ac0b7fb9 100644
--- a/source/slang/hlsl.meta.slang
+++ b/source/slang/hlsl.meta.slang
@@ -9498,7 +9498,8 @@ T ldexp(T x, T exp)
     __target_switch
     {
     case hlsl: __intrinsic_asm "ldexp";
-    case wgsl: __intrinsic_asm "ldexp";
+    // In WGSL spec, ldexp can only take integer as the exponent.
+    case wgsl: __intrinsic_asm "($0 * exp2($1))";
     default:
         return x * exp2(exp);
     }
@@ -9512,7 +9513,8 @@ vector<T, N> ldexp(vector<T, N> x, vector<T, N> exp)
     __target_switch
     {
     case hlsl: __intrinsic_asm "ldexp";
-    case wgsl: __intrinsic_asm "ldexp";
+    // In WGSL spec, ldexp can only take integer as the exponent.
+    case wgsl: __intrinsic_asm "($0 * exp2($1))";
     default:
         return x * exp2(exp);
     }
@@ -9737,13 +9739,14 @@ matrix<T, N, M> log(matrix<T, N, M> x)
 /// @category math
 __generic<T : __BuiltinFloatingPointType>
 [__readNone]
-[require(cpp_cuda_glsl_hlsl_metal_spirv, sm_4_0_version)]
+[require(cpp_cuda_glsl_hlsl_metal_spirv_wgsl, sm_4_0_version)]
 T log10(T x)
 {
     __target_switch
     {
     case hlsl: __intrinsic_asm "log10";
     case metal: __intrinsic_asm "log10";
+    case wgsl: __intrinsic_asm "(log( $0 ) * $S0( 0.43429448190325182765112891891661) )";
     case glsl: __intrinsic_asm "(log( $0 ) * $S0( 0.43429448190325182765112891891661) )";
     case cuda: __intrinsic_asm "$P_log10($0)";
     case cpp: __intrinsic_asm "$P_log10($0)";
@@ -9760,13 +9763,14 @@ T log10(T x)
 
 __generic<T : __BuiltinFloatingPointType, let N : int>
 [__readNone]
-[require(cpp_cuda_glsl_hlsl_metal_spirv, sm_4_0_version)]
+[require(cpp_cuda_glsl_hlsl_metal_spirv_wgsl, sm_4_0_version)]
 vector<T,N> log10(vector<T,N> x)
 {
     __target_switch
     {
     case hlsl: __intrinsic_asm "log10";
     case metal: __intrinsic_asm "log10";
+    case wgsl: __intrinsic_asm "(log( $0 ) * $S0(0.43429448190325182765112891891661) )";
     case glsl: __intrinsic_asm "(log( $0 ) * $S0(0.43429448190325182765112891891661) )";
     case spirv:
     {
-- 
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