Translate NonUniformResourceIndex() calls to Vulkan GLSL (#713)

These calls translate to uses of the `nonuniformEXT` qualifier introduced by the `GL_EXT_nonuniform_qualifier` extension.

The standard library changes in this case are straightforward uses of existing compiler mechanisms. The test case is one of the less pleasant ones where we compare SPIR-V output against SPIR-V generated from a hand-coded GLSL baseline. This is a case where a simpler test type that just checks for specific textual matches in the output (and not whole files) would be better, but that is out of scope for this change.

4 files changed, 51 insertions, 0 deletions

diff --git a/source/slang/hlsl.meta.slang b/source/slang/hlsl.meta.slang
index fb03dfcfc..c666dadd3 100644
--- a/source/slang/hlsl.meta.slang
+++ b/source/slang/hlsl.meta.slang
@@ -871,7 +871,12 @@ __generic<let N : int> float noise(vector<float, N> x);
 /// to this function as necessary in output code, rather than make this

 /// the user's responsibility, so that the default behavior of the language

 /// is more semantically "correct."

+__target_intrinsic(glsl, nonuniformEXT)

+__glsl_extension(GL_EXT_nonuniform_qualifier)

 uint NonUniformResourceIndex(uint index);

+

+__target_intrinsic(glsl, nonuniformEXT)

+__glsl_extension(GL_EXT_nonuniform_qualifier)

 int NonUniformResourceIndex(int index);

 

 // Normalize a vector

diff --git a/source/slang/hlsl.meta.slang.h b/source/slang/hlsl.meta.slang.h
index e1e080d25..2db710ccb 100644
--- a/source/slang/hlsl.meta.slang.h
+++ b/source/slang/hlsl.meta.slang.h
@@ -916,7 +916,12 @@ SLANG_RAW("/// Note: a future version of Slang may take responsibility for inser
 SLANG_RAW("/// to this function as necessary in output code, rather than make this\n")
 SLANG_RAW("/// the user's responsibility, so that the default behavior of the language\n")
 SLANG_RAW("/// is more semantically \"correct.\"\n")
+SLANG_RAW("__target_intrinsic(glsl, nonuniformEXT)\n")
+SLANG_RAW("__glsl_extension(GL_EXT_nonuniform_qualifier)\n")
 SLANG_RAW("uint NonUniformResourceIndex(uint index);\n")
+SLANG_RAW("\n")
+SLANG_RAW("__target_intrinsic(glsl, nonuniformEXT)\n")
+SLANG_RAW("__glsl_extension(GL_EXT_nonuniform_qualifier)\n")
 SLANG_RAW("int NonUniformResourceIndex(int index);\n")
 SLANG_RAW("\n")
 SLANG_RAW("// Normalize a vector\n")
diff --git a/tests/cross-compile/non-uniform-indexing.slang b/tests/cross-compile/non-uniform-indexing.slang
new file mode 100644
index 000000000..647742df8
--- /dev/null
+++ b/tests/cross-compile/non-uniform-indexing.slang
@@ -0,0 +1,13 @@
+//TEST:CROSS_COMPILE:-target spirv-assembly -entry main -stage fragment
+
+// Confirm that `NonUniformResourceIndex` translates to SPIR-V as expeted
+
+Texture2D t[10];
+SamplerState s;
+
+float4 main(
+    float3 uv : UV)
+    : SV_Target
+{
+    return t[NonUniformResourceIndex(int(uv.z))].Sample(s, uv.xy);
+}
diff --git a/tests/cross-compile/non-uniform-indexing.slang.glsl b/tests/cross-compile/non-uniform-indexing.slang.glsl
new file mode 100644
index 000000000..83f63c70d
--- /dev/null
+++ b/tests/cross-compile/non-uniform-indexing.slang.glsl
@@ -0,0 +1,28 @@
+//TEST_IGNORE_FILE
+#version 450
+
+#extension GL_EXT_nonuniform_qualifier : require
+
+layout(binding = 0)
+uniform texture2D t_0[10];
+
+layout(binding = 1)
+uniform sampler s_0;
+
+layout(location = 0)
+out vec4 _S1;
+
+layout(location = 0)
+in vec3 _S2;
+
+void main()
+{
+    vec3 _S3 = _S2;
+
+    int _S4 = nonuniformEXT(int(_S3.z));
+
+    vec4 _S5 = texture(sampler2D(t_0[_S4],s_0), _S3.xy);
+
+    _S1 = _S5;
+    return;
+}