Merge pull request #1862 from flokart-world/feature/flatten-ubo-for-hlsl

HLSL: Make --flatten-ubo work correctly

43 files changed, 1318 insertions, 8 deletions

diff --git a/main.cpp b/main.cpp
index 4e9fa849..dc3ca489 100644
--- a/main.cpp
+++ b/main.cpp
@@ -791,6 +791,9 @@ static void print_help_hlsl()
 	// clang-format off
 	fprintf(stderr, "\nHLSL options:\n"
 	                "\t[--shader-model]:\n\t\tEnables a specific shader model, e.g. --shader-model 50 for SM 5.0.\n"
+	                "\t[--flatten-ubo]:\n\t\tEmit UBOs as plain uniform arrays.\n"
+	                "\t\tE.g.: uniform MyUBO { vec4 a; float b, c, d, e; }; will be emitted as uniform float4 MyUBO[2];\n"
+	                "\t\tCaveat: You cannot mix and match floating-point and integer in the same UBO with this option.\n"
 	                "\t[--hlsl-enable-compat]:\n\t\tAllow point size and point coord to be used, even if they won't work as expected.\n"
 	                "\t\tPointSize is ignored, and PointCoord returns (0.5, 0.5).\n"
 	                "\t[--hlsl-support-nonzero-basevertex-baseinstance]:\n\t\tSupport base vertex and base instance by emitting a special cbuffer declared as:\n"
diff --git a/reference/opt/shaders-hlsl/flatten/array.flatten.vert b/reference/opt/shaders-hlsl/flatten/array.flatten.vert
new file mode 100644
index 00000000..c709893c
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/array.flatten.vert
@@ -0,0 +1,28 @@
+uniform float4 UBO[56];
+
+static float4 gl_Position;
+static float4 aVertex;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = (mul(aVertex, float4x4(UBO[40], UBO[41], UBO[42], UBO[43])) + UBO[55]) + ((UBO[50] + UBO[45]) + UBO[54].x.xxxx);
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/basic.flatten.vert b/reference/opt/shaders-hlsl/flatten/basic.flatten.vert
new file mode 100644
index 00000000..778acd48
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/basic.flatten.vert
@@ -0,0 +1,35 @@
+uniform float4 UBO[4];
+
+static float4 gl_Position;
+static float4 aVertex;
+static float3 vNormal;
+static float3 aNormal;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+    float3 aNormal : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float3 vNormal : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3]));
+    vNormal = aNormal;
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    aNormal = stage_input.aNormal;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vNormal = vNormal;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/copy.flatten.vert b/reference/opt/shaders-hlsl/flatten/copy.flatten.vert
new file mode 100644
index 00000000..5d857ad6
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/copy.flatten.vert
@@ -0,0 +1,50 @@
+struct Light
+{
+    float3 Position;
+    float Radius;
+    float4 Color;
+};
+
+uniform float4 UBO[12];
+
+static float4 gl_Position;
+static float4 aVertex;
+static float4 vColor;
+static float3 aNormal;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+    float3 aNormal : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 vColor : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3]));
+    vColor = 0.0f.xxxx;
+    for (int _96 = 0; _96 < 4; )
+    {
+        Light _51 = {UBO[_96 * 2 + 4].xyz, UBO[_96 * 2 + 4].w, UBO[_96 * 2 + 5]};
+        float3 _68 = aVertex.xyz - _51.Position;
+        vColor += ((UBO[_96 * 2 + 5] * clamp(1.0f - (length(_68) / _51.Radius), 0.0f, 1.0f)) * dot(aNormal, normalize(_68)));
+        _96++;
+        continue;
+    }
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    aNormal = stage_input.aNormal;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vColor = vColor;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/dynamic.flatten.vert b/reference/opt/shaders-hlsl/flatten/dynamic.flatten.vert
new file mode 100644
index 00000000..98d5e1b3
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/dynamic.flatten.vert
@@ -0,0 +1,49 @@
+struct Light
+{
+    float3 Position;
+    float Radius;
+    float4 Color;
+};
+
+uniform float4 UBO[12];
+
+static float4 gl_Position;
+static float4 aVertex;
+static float4 vColor;
+static float3 aNormal;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+    float3 aNormal : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 vColor : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3]));
+    vColor = 0.0f.xxxx;
+    for (int _82 = 0; _82 < 4; )
+    {
+        float3 _54 = aVertex.xyz - UBO[_82 * 2 + 4].xyz;
+        vColor += ((UBO[_82 * 2 + 5] * clamp(1.0f - (length(_54) / UBO[_82 * 2 + 4].w), 0.0f, 1.0f)) * dot(aNormal, normalize(_54)));
+        _82++;
+        continue;
+    }
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    aNormal = stage_input.aNormal;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vColor = vColor;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/matrix-conversion.flatten.frag b/reference/opt/shaders-hlsl/flatten/matrix-conversion.flatten.frag
new file mode 100644
index 00000000..59ec525f
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/matrix-conversion.flatten.frag
@@ -0,0 +1,29 @@
+uniform float4 UBO[4];
+
+static float3 FragColor;
+static float3 vNormal;
+
+struct SPIRV_Cross_Input
+{
+    nointerpolation float3 vNormal : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float3 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    float4x4 _19 = float4x4(UBO[0], UBO[1], UBO[2], UBO[3]);
+    FragColor = mul(vNormal, float3x3(_19[0].xyz, _19[1].xyz, _19[2].xyz));
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    vNormal = stage_input.vNormal;
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/matrixindex.flatten.vert b/reference/opt/shaders-hlsl/flatten/matrixindex.flatten.vert
new file mode 100644
index 00000000..b69a72dc
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/matrixindex.flatten.vert
@@ -0,0 +1,41 @@
+uniform float4 UBO[14];
+
+static float4 gl_Position;
+static float4 oA;
+static float4 oB;
+static float4 oC;
+static float4 oD;
+static float4 oE;
+
+struct SPIRV_Cross_Output
+{
+    float4 oA : TEXCOORD0;
+    float4 oB : TEXCOORD1;
+    float4 oC : TEXCOORD2;
+    float4 oD : TEXCOORD3;
+    float4 oE : TEXCOORD4;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = 0.0f.xxxx;
+    oA = UBO[1];
+    oB = float4(UBO[4].y, UBO[5].y, UBO[6].y, UBO[7].y);
+    oC = UBO[9];
+    oD = float4(UBO[10].x, UBO[11].x, UBO[12].x, UBO[13].x);
+    oE = float4(UBO[1].z, UBO[6].y, UBO[9].z, UBO[12].y);
+}
+
+SPIRV_Cross_Output main()
+{
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.oA = oA;
+    stage_output.oB = oB;
+    stage_output.oC = oC;
+    stage_output.oD = oD;
+    stage_output.oE = oE;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/multiindex.flatten.vert b/reference/opt/shaders-hlsl/flatten/multiindex.flatten.vert
new file mode 100644
index 00000000..f21f05ec
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/multiindex.flatten.vert
@@ -0,0 +1,28 @@
+uniform float4 UBO[15];
+
+static float4 gl_Position;
+static int2 aIndex;
+
+struct SPIRV_Cross_Input
+{
+    int2 aIndex : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = UBO[aIndex.x * 5 + aIndex.y * 1 + 0];
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aIndex = stage_input.aIndex;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/push-constant.flatten.vert b/reference/opt/shaders-hlsl/flatten/push-constant.flatten.vert
new file mode 100644
index 00000000..5bfb4dc0
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/push-constant.flatten.vert
@@ -0,0 +1,35 @@
+uniform float4 PushMe[6];
+
+static float4 gl_Position;
+static float4 Pos;
+static float2 vRot;
+static float2 Rot;
+
+struct SPIRV_Cross_Input
+{
+    float2 Rot : TEXCOORD0;
+    float4 Pos : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float2 vRot : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(Pos, float4x4(PushMe[0], PushMe[1], PushMe[2], PushMe[3]));
+    vRot = mul(Rot, float2x2(PushMe[4].xy, PushMe[4].zw)) + PushMe[5].z.xx;
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    Pos = stage_input.Pos;
+    Rot = stage_input.Rot;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vRot = vRot;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/rowmajor.flatten.vert b/reference/opt/shaders-hlsl/flatten/rowmajor.flatten.vert
new file mode 100644
index 00000000..2560484e
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/rowmajor.flatten.vert
@@ -0,0 +1,28 @@
+uniform float4 UBO[12];
+
+static float4 gl_Position;
+static float4 aVertex;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3])) + mul(aVertex, transpose(float4x4(UBO[4], UBO[5], UBO[6], UBO[7])));
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/struct.flatten.vert b/reference/opt/shaders-hlsl/flatten/struct.flatten.vert
new file mode 100644
index 00000000..41ad8ce9
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/struct.flatten.vert
@@ -0,0 +1,44 @@
+struct Light
+{
+    float3 Position;
+    float Radius;
+    float4 Color;
+};
+
+uniform float4 UBO[6];
+
+static float4 gl_Position;
+static float4 aVertex;
+static float4 vColor;
+static float3 aNormal;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+    float3 aNormal : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 vColor : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3]));
+    vColor = 0.0f.xxxx;
+    float3 _39 = aVertex.xyz - UBO[4].xyz;
+    vColor += ((UBO[5] * clamp(1.0f - (length(_39) / UBO[4].w), 0.0f, 1.0f)) * dot(aNormal, normalize(_39)));
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    aNormal = stage_input.aNormal;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vColor = vColor;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/struct.rowmajor.flatten.vert b/reference/opt/shaders-hlsl/flatten/struct.rowmajor.flatten.vert
new file mode 100644
index 00000000..bb702907
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/struct.rowmajor.flatten.vert
@@ -0,0 +1,43 @@
+struct Foo
+{
+    column_major float3x4 MVP0;
+    column_major float3x4 MVP1;
+};
+
+uniform float4 UBO[8];
+
+static float4 v0;
+static float4 v1;
+static float3 V0;
+static float3 V1;
+
+struct SPIRV_Cross_Input
+{
+    float4 v0 : TEXCOORD0;
+    float4 v1 : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float3 V0 : TEXCOORD0;
+    float3 V1 : TEXCOORD1;
+};
+
+void vert_main()
+{
+    Foo _19 = {transpose(float4x3(UBO[0].xyz, UBO[1].xyz, UBO[2].xyz, UBO[3].xyz)), transpose(float4x3(UBO[4].xyz, UBO[5].xyz, UBO[6].xyz, UBO[7].xyz))};
+    Foo _20 = _19;
+    V0 = mul(_20.MVP0, v0);
+    V1 = mul(_20.MVP1, v1);
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    v0 = stage_input.v0;
+    v1 = stage_input.v1;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.V0 = V0;
+    stage_output.V1 = V1;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/swizzle.flatten.vert b/reference/opt/shaders-hlsl/flatten/swizzle.flatten.vert
new file mode 100644
index 00000000..1091a17e
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/swizzle.flatten.vert
@@ -0,0 +1,45 @@
+uniform float4 UBO[8];
+
+static float4 gl_Position;
+static float4 oA;
+static float4 oB;
+static float4 oC;
+static float4 oD;
+static float4 oE;
+static float4 oF;
+
+struct SPIRV_Cross_Output
+{
+    float4 oA : TEXCOORD0;
+    float4 oB : TEXCOORD1;
+    float4 oC : TEXCOORD2;
+    float4 oD : TEXCOORD3;
+    float4 oE : TEXCOORD4;
+    float4 oF : TEXCOORD5;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = 0.0f.xxxx;
+    oA = UBO[0];
+    oB = float4(UBO[1].xy, UBO[1].zw);
+    oC = float4(UBO[2].x, UBO[3].xyz);
+    oD = float4(UBO[4].xyz, UBO[4].w);
+    oE = float4(UBO[5].x, UBO[5].y, UBO[5].z, UBO[5].w);
+    oF = float4(UBO[6].x, UBO[6].zw, UBO[7].x);
+}
+
+SPIRV_Cross_Output main()
+{
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.oA = oA;
+    stage_output.oB = oB;
+    stage_output.oC = oC;
+    stage_output.oD = oD;
+    stage_output.oE = oE;
+    stage_output.oF = oF;
+    return stage_output;
+}
diff --git a/reference/opt/shaders-hlsl/flatten/types.flatten.frag b/reference/opt/shaders-hlsl/flatten/types.flatten.frag
new file mode 100644
index 00000000..feb0b360
--- /dev/null
+++ b/reference/opt/shaders-hlsl/flatten/types.flatten.frag
@@ -0,0 +1,23 @@
+uniform int4 UBO1[2];
+uniform uint4 UBO2[2];
+uniform float4 UBO0[2];
+
+static float4 FragColor;
+
+struct SPIRV_Cross_Output
+{
+    float4 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    FragColor = ((((float4(UBO1[0]) + float4(UBO1[1])) + float4(UBO2[0])) + float4(UBO2[1])) + UBO0[0]) + UBO0[1];
+}
+
+SPIRV_Cross_Output main()
+{
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/array.flatten.vert b/reference/shaders-hlsl/flatten/array.flatten.vert
new file mode 100644
index 00000000..948a198e
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/array.flatten.vert
@@ -0,0 +1,30 @@
+uniform float4 UBO[56];
+
+static float4 gl_Position;
+static float4 aVertex;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    float4 a4 = UBO[23];
+    float4 offset = (UBO[50] + UBO[45]) + UBO[54].x.xxxx;
+    gl_Position = (mul(aVertex, float4x4(UBO[40], UBO[41], UBO[42], UBO[43])) + UBO[55]) + offset;
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/basic.flatten.vert b/reference/shaders-hlsl/flatten/basic.flatten.vert
new file mode 100644
index 00000000..778acd48
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/basic.flatten.vert
@@ -0,0 +1,35 @@
+uniform float4 UBO[4];
+
+static float4 gl_Position;
+static float4 aVertex;
+static float3 vNormal;
+static float3 aNormal;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+    float3 aNormal : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float3 vNormal : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3]));
+    vNormal = aNormal;
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    aNormal = stage_input.aNormal;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vNormal = vNormal;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/copy.flatten.vert b/reference/shaders-hlsl/flatten/copy.flatten.vert
new file mode 100644
index 00000000..f85c890b
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/copy.flatten.vert
@@ -0,0 +1,53 @@
+struct Light
+{
+    float3 Position;
+    float Radius;
+    float4 Color;
+};
+
+uniform float4 UBO[12];
+
+static float4 gl_Position;
+static float4 aVertex;
+static float4 vColor;
+static float3 aNormal;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+    float3 aNormal : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 vColor : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3]));
+    vColor = 0.0f.xxxx;
+    Light light;
+    for (int i = 0; i < 4; i++)
+    {
+        Light _51 = {UBO[i * 2 + 4].xyz, UBO[i * 2 + 4].w, UBO[i * 2 + 5]};
+        Light _52 = _51;
+        light.Position = _52.Position;
+        light.Radius = _52.Radius;
+        light.Color = _52.Color;
+        float3 L = aVertex.xyz - light.Position;
+        vColor += ((UBO[i * 2 + 5] * clamp(1.0f - (length(L) / light.Radius), 0.0f, 1.0f)) * dot(aNormal, normalize(L)));
+    }
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    aNormal = stage_input.aNormal;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vColor = vColor;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/dynamic.flatten.vert b/reference/shaders-hlsl/flatten/dynamic.flatten.vert
new file mode 100644
index 00000000..787eefcd
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/dynamic.flatten.vert
@@ -0,0 +1,47 @@
+struct Light
+{
+    float3 Position;
+    float Radius;
+    float4 Color;
+};
+
+uniform float4 UBO[12];
+
+static float4 gl_Position;
+static float4 aVertex;
+static float4 vColor;
+static float3 aNormal;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+    float3 aNormal : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 vColor : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3]));
+    vColor = 0.0f.xxxx;
+    for (int i = 0; i < 4; i++)
+    {
+        float3 L = aVertex.xyz - UBO[i * 2 + 4].xyz;
+        vColor += ((UBO[i * 2 + 5] * clamp(1.0f - (length(L) / UBO[i * 2 + 4].w), 0.0f, 1.0f)) * dot(aNormal, normalize(L)));
+    }
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    aNormal = stage_input.aNormal;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vColor = vColor;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/matrix-conversion.flatten.frag b/reference/shaders-hlsl/flatten/matrix-conversion.flatten.frag
new file mode 100644
index 00000000..59ec525f
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/matrix-conversion.flatten.frag
@@ -0,0 +1,29 @@
+uniform float4 UBO[4];
+
+static float3 FragColor;
+static float3 vNormal;
+
+struct SPIRV_Cross_Input
+{
+    nointerpolation float3 vNormal : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float3 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    float4x4 _19 = float4x4(UBO[0], UBO[1], UBO[2], UBO[3]);
+    FragColor = mul(vNormal, float3x3(_19[0].xyz, _19[1].xyz, _19[2].xyz));
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    vNormal = stage_input.vNormal;
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/matrixindex.flatten.vert b/reference/shaders-hlsl/flatten/matrixindex.flatten.vert
new file mode 100644
index 00000000..b69a72dc
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/matrixindex.flatten.vert
@@ -0,0 +1,41 @@
+uniform float4 UBO[14];
+
+static float4 gl_Position;
+static float4 oA;
+static float4 oB;
+static float4 oC;
+static float4 oD;
+static float4 oE;
+
+struct SPIRV_Cross_Output
+{
+    float4 oA : TEXCOORD0;
+    float4 oB : TEXCOORD1;
+    float4 oC : TEXCOORD2;
+    float4 oD : TEXCOORD3;
+    float4 oE : TEXCOORD4;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = 0.0f.xxxx;
+    oA = UBO[1];
+    oB = float4(UBO[4].y, UBO[5].y, UBO[6].y, UBO[7].y);
+    oC = UBO[9];
+    oD = float4(UBO[10].x, UBO[11].x, UBO[12].x, UBO[13].x);
+    oE = float4(UBO[1].z, UBO[6].y, UBO[9].z, UBO[12].y);
+}
+
+SPIRV_Cross_Output main()
+{
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.oA = oA;
+    stage_output.oB = oB;
+    stage_output.oC = oC;
+    stage_output.oD = oD;
+    stage_output.oE = oE;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/multiindex.flatten.vert b/reference/shaders-hlsl/flatten/multiindex.flatten.vert
new file mode 100644
index 00000000..f21f05ec
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/multiindex.flatten.vert
@@ -0,0 +1,28 @@
+uniform float4 UBO[15];
+
+static float4 gl_Position;
+static int2 aIndex;
+
+struct SPIRV_Cross_Input
+{
+    int2 aIndex : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = UBO[aIndex.x * 5 + aIndex.y * 1 + 0];
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aIndex = stage_input.aIndex;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/push-constant.flatten.vert b/reference/shaders-hlsl/flatten/push-constant.flatten.vert
new file mode 100644
index 00000000..5bfb4dc0
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/push-constant.flatten.vert
@@ -0,0 +1,35 @@
+uniform float4 PushMe[6];
+
+static float4 gl_Position;
+static float4 Pos;
+static float2 vRot;
+static float2 Rot;
+
+struct SPIRV_Cross_Input
+{
+    float2 Rot : TEXCOORD0;
+    float4 Pos : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float2 vRot : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(Pos, float4x4(PushMe[0], PushMe[1], PushMe[2], PushMe[3]));
+    vRot = mul(Rot, float2x2(PushMe[4].xy, PushMe[4].zw)) + PushMe[5].z.xx;
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    Pos = stage_input.Pos;
+    Rot = stage_input.Rot;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vRot = vRot;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/rowmajor.flatten.vert b/reference/shaders-hlsl/flatten/rowmajor.flatten.vert
new file mode 100644
index 00000000..801def3b
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/rowmajor.flatten.vert
@@ -0,0 +1,29 @@
+uniform float4 UBO[12];
+
+static float4 gl_Position;
+static float4 aVertex;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    float2 v = mul(transpose(float4x2(UBO[8].xy, UBO[9].xy, UBO[10].xy, UBO[11].xy)), aVertex);
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3])) + mul(aVertex, transpose(float4x4(UBO[4], UBO[5], UBO[6], UBO[7])));
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/struct.flatten.vert b/reference/shaders-hlsl/flatten/struct.flatten.vert
new file mode 100644
index 00000000..9b97bf59
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/struct.flatten.vert
@@ -0,0 +1,44 @@
+struct Light
+{
+    float3 Position;
+    float Radius;
+    float4 Color;
+};
+
+uniform float4 UBO[6];
+
+static float4 gl_Position;
+static float4 aVertex;
+static float4 vColor;
+static float3 aNormal;
+
+struct SPIRV_Cross_Input
+{
+    float4 aVertex : TEXCOORD0;
+    float3 aNormal : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float4 vColor : TEXCOORD0;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = mul(aVertex, float4x4(UBO[0], UBO[1], UBO[2], UBO[3]));
+    vColor = 0.0f.xxxx;
+    float3 L = aVertex.xyz - UBO[4].xyz;
+    vColor += ((UBO[5] * clamp(1.0f - (length(L) / UBO[4].w), 0.0f, 1.0f)) * dot(aNormal, normalize(L)));
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    aVertex = stage_input.aVertex;
+    aNormal = stage_input.aNormal;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.vColor = vColor;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/struct.rowmajor.flatten.vert b/reference/shaders-hlsl/flatten/struct.rowmajor.flatten.vert
new file mode 100644
index 00000000..39b0a808
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/struct.rowmajor.flatten.vert
@@ -0,0 +1,48 @@
+struct Foo
+{
+    column_major float3x4 MVP0;
+    column_major float3x4 MVP1;
+};
+
+uniform float4 UBO[8];
+
+static float4 v0;
+static float4 v1;
+static float3 V0;
+static float3 V1;
+
+struct SPIRV_Cross_Input
+{
+    float4 v0 : TEXCOORD0;
+    float4 v1 : TEXCOORD1;
+};
+
+struct SPIRV_Cross_Output
+{
+    float3 V0 : TEXCOORD0;
+    float3 V1 : TEXCOORD1;
+};
+
+void vert_main()
+{
+    Foo _19 = {transpose(float4x3(UBO[0].xyz, UBO[1].xyz, UBO[2].xyz, UBO[3].xyz)), transpose(float4x3(UBO[4].xyz, UBO[5].xyz, UBO[6].xyz, UBO[7].xyz))};
+    Foo _20 = _19;
+    Foo f;
+    f.MVP0 = _20.MVP0;
+    f.MVP1 = _20.MVP1;
+    float3 a = mul(f.MVP0, v0);
+    float3 b = mul(f.MVP1, v1);
+    V0 = a;
+    V1 = b;
+}
+
+SPIRV_Cross_Output main(SPIRV_Cross_Input stage_input)
+{
+    v0 = stage_input.v0;
+    v1 = stage_input.v1;
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.V0 = V0;
+    stage_output.V1 = V1;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/swizzle.flatten.vert b/reference/shaders-hlsl/flatten/swizzle.flatten.vert
new file mode 100644
index 00000000..1091a17e
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/swizzle.flatten.vert
@@ -0,0 +1,45 @@
+uniform float4 UBO[8];
+
+static float4 gl_Position;
+static float4 oA;
+static float4 oB;
+static float4 oC;
+static float4 oD;
+static float4 oE;
+static float4 oF;
+
+struct SPIRV_Cross_Output
+{
+    float4 oA : TEXCOORD0;
+    float4 oB : TEXCOORD1;
+    float4 oC : TEXCOORD2;
+    float4 oD : TEXCOORD3;
+    float4 oE : TEXCOORD4;
+    float4 oF : TEXCOORD5;
+    float4 gl_Position : SV_Position;
+};
+
+void vert_main()
+{
+    gl_Position = 0.0f.xxxx;
+    oA = UBO[0];
+    oB = float4(UBO[1].xy, UBO[1].zw);
+    oC = float4(UBO[2].x, UBO[3].xyz);
+    oD = float4(UBO[4].xyz, UBO[4].w);
+    oE = float4(UBO[5].x, UBO[5].y, UBO[5].z, UBO[5].w);
+    oF = float4(UBO[6].x, UBO[6].zw, UBO[7].x);
+}
+
+SPIRV_Cross_Output main()
+{
+    vert_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.gl_Position = gl_Position;
+    stage_output.oA = oA;
+    stage_output.oB = oB;
+    stage_output.oC = oC;
+    stage_output.oD = oD;
+    stage_output.oE = oE;
+    stage_output.oF = oF;
+    return stage_output;
+}
diff --git a/reference/shaders-hlsl/flatten/types.flatten.frag b/reference/shaders-hlsl/flatten/types.flatten.frag
new file mode 100644
index 00000000..feb0b360
--- /dev/null
+++ b/reference/shaders-hlsl/flatten/types.flatten.frag
@@ -0,0 +1,23 @@
+uniform int4 UBO1[2];
+uniform uint4 UBO2[2];
+uniform float4 UBO0[2];
+
+static float4 FragColor;
+
+struct SPIRV_Cross_Output
+{
+    float4 FragColor : SV_Target0;
+};
+
+void frag_main()
+{
+    FragColor = ((((float4(UBO1[0]) + float4(UBO1[1])) + float4(UBO2[0])) + float4(UBO2[1])) + UBO0[0]) + UBO0[1];
+}
+
+SPIRV_Cross_Output main()
+{
+    frag_main();
+    SPIRV_Cross_Output stage_output;
+    stage_output.FragColor = FragColor;
+    return stage_output;
+}
diff --git a/shaders-hlsl/flatten/array.flatten.vert b/shaders-hlsl/flatten/array.flatten.vert
new file mode 100644
index 00000000..fa6da076
--- /dev/null
+++ b/shaders-hlsl/flatten/array.flatten.vert
@@ -0,0 +1,19 @@
+#version 310 es
+
+layout(std140) uniform UBO
+{
+    vec4 A4[5][4][2];
+    mat4 uMVP;
+    vec4 A1[2];
+    vec4 A2[2][3];
+    float A3[3];
+    vec4 Offset;
+};
+layout(location = 0) in vec4 aVertex;
+
+void main()
+{
+    vec4 a4 = A4[2][3][1]; // 2 * (4 * 2) + 3 * 2 + 1 = 16 + 6 + 1 = 23.
+    vec4 offset = A2[1][1] + A1[1] + A3[2];
+    gl_Position = uMVP * aVertex + Offset + offset;
+}
diff --git a/shaders-hlsl/flatten/basic.flatten.vert b/shaders-hlsl/flatten/basic.flatten.vert
new file mode 100644
index 00000000..e60a9067
--- /dev/null
+++ b/shaders-hlsl/flatten/basic.flatten.vert
@@ -0,0 +1,16 @@
+#version 310 es
+
+layout(std140) uniform UBO
+{
+    mat4 uMVP;
+};
+
+layout(location = 0) in vec4 aVertex;
+layout(location = 1) in vec3 aNormal;
+layout(location = 0) out vec3 vNormal;
+
+void main()
+{
+    gl_Position = uMVP * aVertex;
+    vNormal = aNormal;
+}
diff --git a/shaders-hlsl/flatten/copy.flatten.vert b/shaders-hlsl/flatten/copy.flatten.vert
new file mode 100644
index 00000000..4f1b8805
--- /dev/null
+++ b/shaders-hlsl/flatten/copy.flatten.vert
@@ -0,0 +1,34 @@
+#version 310 es
+
+struct Light
+{
+    vec3 Position;
+    float Radius;
+
+    vec4 Color;
+};
+
+layout(std140) uniform UBO
+{
+    mat4 uMVP;
+
+    Light lights[4];
+};
+
+layout(location = 0) in vec4 aVertex;
+layout(location = 1) in vec3 aNormal;
+layout(location = 0) out vec4 vColor;
+
+void main()
+{
+    gl_Position = uMVP * aVertex;
+
+    vColor = vec4(0.0);
+
+    for (int i = 0; i < 4; ++i)
+    {
+        Light light = lights[i];
+        vec3 L = aVertex.xyz - light.Position;
+        vColor += dot(aNormal, normalize(L)) * (clamp(1.0 - length(L) / light.Radius, 0.0, 1.0) * lights[i].Color);
+    }
+}
diff --git a/shaders-hlsl/flatten/dynamic.flatten.vert b/shaders-hlsl/flatten/dynamic.flatten.vert
new file mode 100644
index 00000000..a341d452
--- /dev/null
+++ b/shaders-hlsl/flatten/dynamic.flatten.vert
@@ -0,0 +1,33 @@
+#version 310 es
+
+struct Light
+{
+    vec3 Position;
+    float Radius;
+
+    vec4 Color;
+};
+
+layout(std140) uniform UBO
+{
+    mat4 uMVP;
+
+    Light lights[4];
+};
+
+layout(location = 0) in vec4 aVertex;
+layout(location = 1) in vec3 aNormal;
+layout(location = 0) out vec4 vColor;
+
+void main()
+{
+    gl_Position = uMVP * aVertex;
+
+    vColor = vec4(0.0);
+
+    for (int i = 0; i < 4; ++i)
+    {
+        vec3 L = aVertex.xyz - lights[i].Position;
+        vColor += dot(aNormal, normalize(L)) * (clamp(1.0 - length(L) / lights[i].Radius, 0.0, 1.0) * lights[i].Color);
+    }
+}
diff --git a/shaders-hlsl/flatten/matrix-conversion.flatten.frag b/shaders-hlsl/flatten/matrix-conversion.flatten.frag
new file mode 100644
index 00000000..427825c3
--- /dev/null
+++ b/shaders-hlsl/flatten/matrix-conversion.flatten.frag
@@ -0,0 +1,14 @@
+#version 310 es
+precision mediump float;
+layout(location = 0) out vec3 FragColor;
+layout(location = 0) flat in vec3 vNormal;
+
+layout(binding = 0, std140) uniform UBO
+{
+	mat4 m;
+};
+
+void main()
+{
+	FragColor = mat3(m) * vNormal;
+}
diff --git a/shaders-hlsl/flatten/matrixindex.flatten.vert b/shaders-hlsl/flatten/matrixindex.flatten.vert
new file mode 100644
index 00000000..0ee78384
--- /dev/null
+++ b/shaders-hlsl/flatten/matrixindex.flatten.vert
@@ -0,0 +1,25 @@
+#version 310 es
+
+layout(std140) uniform UBO
+{
+    layout(column_major) mat4 M1C;
+    layout(row_major) mat4 M1R;
+    layout(column_major) mat2x4 M2C;
+    layout(row_major) mat2x4 M2R;
+};
+
+layout(location = 0) out vec4 oA;
+layout(location = 1) out vec4 oB;
+layout(location = 2) out vec4 oC;
+layout(location = 3) out vec4 oD;
+layout(location = 4) out vec4 oE;
+
+void main()
+{
+	gl_Position = vec4(0.0);
+	oA = M1C[1];
+	oB = M1R[1];
+	oC = M2C[1];
+	oD = M2R[0];
+	oE = vec4(M1C[1][2], M1R[1][2], M2C[1][2], M2R[1][2]);
+}
diff --git a/shaders-hlsl/flatten/multiindex.flatten.vert b/shaders-hlsl/flatten/multiindex.flatten.vert
new file mode 100644
index 00000000..0b471d86
--- /dev/null
+++ b/shaders-hlsl/flatten/multiindex.flatten.vert
@@ -0,0 +1,13 @@
+#version 310 es
+
+layout(std140) uniform UBO
+{
+    vec4 Data[3][5];
+};
+
+layout(location = 0) in ivec2 aIndex;
+
+void main()
+{
+    gl_Position = Data[aIndex.x][aIndex.y];
+}
diff --git a/shaders-hlsl/flatten/push-constant.flatten.vert b/shaders-hlsl/flatten/push-constant.flatten.vert
new file mode 100644
index 00000000..c7b1b42e
--- /dev/null
+++ b/shaders-hlsl/flatten/push-constant.flatten.vert
@@ -0,0 +1,17 @@
+#version 310 es
+
+layout(push_constant, std430) uniform PushMe
+{
+   mat4 MVP;
+   mat2 Rot; // The MatrixStride will be 8 here.
+   float Arr[4];
+} registers;
+
+layout(location = 0) in vec2 Rot;
+layout(location = 1) in vec4 Pos;
+layout(location = 0) out vec2 vRot;
+void main()
+{
+   gl_Position = registers.MVP * Pos;
+   vRot = registers.Rot * Rot + registers.Arr[2]; // Constant access should work even if array stride is just 4 here.
+}
diff --git a/shaders-hlsl/flatten/rowmajor.flatten.vert b/shaders-hlsl/flatten/rowmajor.flatten.vert
new file mode 100644
index 00000000..88c468c8
--- /dev/null
+++ b/shaders-hlsl/flatten/rowmajor.flatten.vert
@@ -0,0 +1,16 @@
+#version 310 es
+
+layout(std140) uniform UBO
+{
+    layout(column_major) mat4 uMVPR;
+    layout(row_major) mat4 uMVPC;
+    layout(row_major) mat2x4 uMVP;
+};
+
+layout(location = 0) in vec4 aVertex;
+
+void main()
+{
+	vec2 v = aVertex * uMVP;
+	gl_Position = uMVPR * aVertex + uMVPC * aVertex;
+}
diff --git a/shaders-hlsl/flatten/struct.flatten.vert b/shaders-hlsl/flatten/struct.flatten.vert
new file mode 100644
index 00000000..936bb41b
--- /dev/null
+++ b/shaders-hlsl/flatten/struct.flatten.vert
@@ -0,0 +1,30 @@
+#version 310 es
+
+struct Light
+{
+    vec3 Position;
+    float Radius;
+
+    vec4 Color;
+};
+
+layout(std140) uniform UBO
+{
+    mat4 uMVP;
+
+    Light light;
+};
+
+layout(location = 0) in vec4 aVertex;
+layout(location = 1) in vec3 aNormal;
+layout(location = 0) out vec4 vColor;
+
+void main()
+{
+    gl_Position = uMVP * aVertex;
+
+    vColor = vec4(0.0);
+
+    vec3 L = aVertex.xyz - light.Position;
+    vColor += dot(aNormal, normalize(L)) * (clamp(1.0 - length(L) / light.Radius, 0.0, 1.0) * light.Color);
+}
diff --git a/shaders-hlsl/flatten/struct.rowmajor.flatten.vert b/shaders-hlsl/flatten/struct.rowmajor.flatten.vert
new file mode 100644
index 00000000..231389b8
--- /dev/null
+++ b/shaders-hlsl/flatten/struct.rowmajor.flatten.vert
@@ -0,0 +1,26 @@
+#version 310 es
+
+struct Foo
+{
+   mat3x4 MVP0;
+   mat3x4 MVP1;
+};
+
+layout(std140, binding = 0) uniform UBO
+{
+   layout(row_major) Foo foo;
+};
+
+layout(location = 0) in vec4 v0;
+layout(location = 1) in vec4 v1;
+layout(location = 0) out vec3 V0;
+layout(location = 1) out vec3 V1;
+
+void main()
+{
+   Foo f = foo;
+   vec3 a = v0 * f.MVP0;
+   vec3 b = v1 * f.MVP1;
+   V0 = a;
+   V1 = b;
+}
diff --git a/shaders-hlsl/flatten/swizzle.flatten.vert b/shaders-hlsl/flatten/swizzle.flatten.vert
new file mode 100644
index 00000000..fafff773
--- /dev/null
+++ b/shaders-hlsl/flatten/swizzle.flatten.vert
@@ -0,0 +1,47 @@
+#version 310 es
+
+// comments note the 16b alignment boundaries (see GL spec 7.6.2.2 Standard Uniform Block Layout)
+layout(std140, binding = 0) uniform UBO
+{
+    // 16b boundary
+    vec4 A;
+    // 16b boundary
+    vec2 B0;
+    vec2 B1;
+    // 16b boundary
+    float C0;
+    // 16b boundary (vec3 is aligned to 16b)
+    vec3 C1;
+    // 16b boundary
+    vec3 D0;
+    float D1;
+    // 16b boundary
+    float E0;
+    float E1;
+    float E2;
+    float E3;
+    // 16b boundary
+    float F0;
+    vec2 F1;
+    // 16b boundary (vec2 before us is aligned to 8b)
+    float F2;
+};
+
+layout(location = 0) out vec4 oA;
+layout(location = 1) out vec4 oB;
+layout(location = 2) out vec4 oC;
+layout(location = 3) out vec4 oD;
+layout(location = 4) out vec4 oE;
+layout(location = 5) out vec4 oF;
+
+void main()
+{
+    gl_Position = vec4(0.0);
+
+    oA = A;
+    oB = vec4(B0, B1);
+    oC = vec4(C0, C1);
+    oD = vec4(D0, D1);
+    oE = vec4(E0, E1, E2, E3);
+    oF = vec4(F0, F1, F2);
+}
diff --git a/shaders-hlsl/flatten/types.flatten.frag b/shaders-hlsl/flatten/types.flatten.frag
new file mode 100644
index 00000000..faab5b7e
--- /dev/null
+++ b/shaders-hlsl/flatten/types.flatten.frag
@@ -0,0 +1,27 @@
+#version 310 es
+precision mediump float;
+
+layout(std140, binding = 0) uniform UBO0
+{
+   vec4 a;
+   vec4 b;
+};
+
+layout(std140, binding = 0) uniform UBO1
+{
+   ivec4 c;
+   ivec4 d;
+};
+
+layout(std140, binding = 0) uniform UBO2
+{
+   uvec4 e;
+   uvec4 f;
+};
+
+layout(location = 0) out vec4 FragColor;
+
+void main()
+{
+   FragColor = vec4(c) + vec4(d) + vec4(e) + vec4(f) + a + b; 
+}
diff --git a/spirv_glsl.cpp b/spirv_glsl.cpp
index 6d54d878..20739ea8 100644
--- a/spirv_glsl.cpp
+++ b/spirv_glsl.cpp
@@ -9184,8 +9184,13 @@ std::string CompilerGLSL::flattened_access_chain_struct(uint32_t base, const uin
 {
 	std::string expr;
 
-	expr += type_to_glsl_constructor(target_type);
-	expr += "(";
+	if (backend.can_declare_struct_inline)
+	{
+		expr += type_to_glsl_constructor(target_type);
+		expr += "(";
+	}
+	else
+		expr += "{";
 
 	for (uint32_t i = 0; i < uint32_t(target_type.member_types.size()); ++i)
 	{
@@ -9215,7 +9220,7 @@ std::string CompilerGLSL::flattened_access_chain_struct(uint32_t base, const uin
 			expr += tmp;
 	}
 
-	expr += ")";
+	expr += backend.can_declare_struct_inline ? ")" : "}";
 
 	return expr;
 }
@@ -10232,9 +10237,19 @@ void CompilerGLSL::emit_instruction(const Instruction &instruction)
 		// If an expression is mutable and forwardable, we speculate that it is immutable.
 		AccessChainMeta meta;
 		bool ptr_chain = opcode == OpPtrAccessChain;
-		auto e = access_chain(ops[2], &ops[3], length - 3, get<SPIRType>(ops[0]), &meta, ptr_chain);
-
-		auto &expr = set<SPIRExpression>(ops[1], move(e), ops[0], should_forward(ops[2]));
+		auto &target_type = get<SPIRType>(ops[0]);
+		auto e = access_chain(ops[2], &ops[3], length - 3, target_type, &meta, ptr_chain);
+
+		// If the base is flattened UBO of struct type, the expression has to be a composite.
+		// In that case, backends which do not support inline syntax need it to be bound to a temporary.
+		// Otherwise, invalid expressions like ({UBO[0].xyz, UBO[0].w, UBO[1]}).member are emitted.
+		bool requires_temporary = false;
+		if (flattened_buffer_blocks.count(ops[2]) && target_type.basetype == SPIRType::Struct)
+			requires_temporary = !backend.can_declare_struct_inline;
+
+		auto &expr = requires_temporary ?
+                         emit_op(ops[0], ops[1], move(e), false) :
+                         set<SPIRExpression>(ops[1], move(e), ops[0], should_forward(ops[2]));
 
 		auto *backing_variable = maybe_get_backing_variable(ops[2]);
 		expr.loaded_from = backing_variable ? backing_variable->self : ID(ops[2]);
diff --git a/spirv_hlsl.cpp b/spirv_hlsl.cpp
index 3d834774..51d4a1ca 100644
--- a/spirv_hlsl.cpp
+++ b/spirv_hlsl.cpp
@@ -2102,7 +2102,11 @@ void CompilerHLSL::emit_buffer_block(const SPIRVariable &var)
 
 	bool is_uav = var.storage == StorageClassStorageBuffer || has_decoration(type.self, DecorationBufferBlock);
 
-	if (is_uav)
+	if (flattened_buffer_blocks.count(var.self))
+	{
+		emit_buffer_block_flattened(var);
+	}
+	else if (is_uav)
 	{
 		Bitset flags = ir.get_buffer_block_flags(var);
 		bool is_readonly = flags.get(DecorationNonWritable) && !is_hlsl_force_storage_buffer_as_uav(var.self);
@@ -2207,7 +2211,11 @@ void CompilerHLSL::emit_buffer_block(const SPIRVariable &var)
 
 void CompilerHLSL::emit_push_constant_block(const SPIRVariable &var)
 {
-	if (root_constants_layout.empty())
+	if (flattened_buffer_blocks.count(var.self))
+	{
+		emit_buffer_block_flattened(var);
+	}
+	else if (root_constants_layout.empty())
 	{
 		emit_buffer_block(var);
 	}
diff --git a/test_shaders.py b/test_shaders.py
index eca78c32..640baa23 100755
--- a/test_shaders.py
+++ b/test_shaders.py
@@ -462,6 +462,8 @@ def cross_compile_hlsl(shader, spirv, opt, force_no_external_validation, iterati
     hlsl_args = [spirv_cross_path, '--entry', 'main', '--output', hlsl_path, spirv_path, '--hlsl-enable-compat', '--hlsl', '--shader-model', sm, '--iterations', str(iterations)]
     if '.line.' in shader:
         hlsl_args.append('--emit-line-directives')
+    if '.flatten.' in shader:
+        hlsl_args.append('--flatten-ubo')
     if '.force-uav.' in shader:
         hlsl_args.append('--hlsl-force-storage-buffer-as-uav')
     if '.zero-initialize.' in shader: