From 45cc7a18a55a25114932a8e531a25c5d3780414c Mon Sep 17 00:00:00 2001
From: ArielG-NV <159081215+ArielG-NV@users.noreply.github.com>
Date: Fri, 24 May 2024 18:42:48 -0400
Subject: If no sample is set with a `Texture(.*)MS[]` operation, set sample to
 0. (#4225)

* push fix: if no sample, set to 0 for textureMS

* push fixes to hlsl [] operator + test so it will error
---
 source/slang/hlsl.meta.slang | 20 ++++++++++++++++++++
 tests/bugs/gh-4200.slang     | 17 +++++++++++++++++
 2 files changed, 37 insertions(+)
 create mode 100644 tests/bugs/gh-4200.slang

diff --git a/source/slang/hlsl.meta.slang b/source/slang/hlsl.meta.slang
index 11470212a..e1dc8a59a 100644
--- a/source/slang/hlsl.meta.slang
+++ b/source/slang/hlsl.meta.slang
@@ -2564,6 +2564,26 @@ extension __TextureImpl<T,Shape,isArray,1,sampleCount,0,isShadow,isCombined,form
         }
     }
 
+    __subscript(vector<uint, Shape.dimensions+isArray> location) -> T
+    {
+        __glsl_extension(GL_EXT_samplerless_texture_functions)
+        [__readNone]
+        [ForceInline]
+        [require(cpp_glsl_hlsl_metal_spirv, texture_sm_4_1_samplerless)]
+        get
+        {
+            __target_switch
+            {
+                case cpp:
+                case hlsl:
+                    __intrinsic_asm "($0).sample[$1]";
+                case metal:
+                case glsl:
+                case spirv:
+                    return Load(location, 0);
+            }
+        }
+    }
     __subscript(vector<uint, Shape.dimensions+isArray> location, int sampleIndex) -> T
     {
         __glsl_extension(GL_EXT_samplerless_texture_functions)
diff --git a/tests/bugs/gh-4200.slang b/tests/bugs/gh-4200.slang
new file mode 100644
index 000000000..e9ea1d34d
--- /dev/null
+++ b/tests/bugs/gh-4200.slang
@@ -0,0 +1,17 @@
+//TEST:SIMPLE(filecheck=CHECK_SPV): -target spirv -emit-spirv-directly -entry computeMain -stage compute
+//TEST:SIMPLE(filecheck=CHECK_HLSL): -target hlsl -entry computeMain -stage compute
+
+//CHECK_SPV: OpEntryPoint
+//CHECK_HLSL: computeMain
+
+Texture2DMS<uint4> Src : register(t1);
+RWBuffer<uint4>    Dst : register(u2);
+
+[shader("compute")]
+[numthreads(1, 1, 1)]
+void computeMain()
+{
+// CHECK_SPV: Sample %int_0
+// CHECK_HLSL: [{{.*}}1{{.*}}]
+    Dst[0] = Src[int2(1)];
+}
\ No newline at end of file
-- 
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