1#!amber
2
3# Copyright 2020 Google LLC
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9#     http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16
17
18# A test for a bug found by GraphicsFuzz.
19
20# Short description: A fragment shader that finds MSB from LSB
21
22# The test passes because shader always writes red.
23
24SHADER vertex variant_vertex_shader PASSTHROUGH
25
26# variant_fragment_shader is derived from the following GLSL:
27# #version 310 es
28# precision highp float;
29# precision highp int;
30#
31# layout(location = 0) out vec4 _GLF_color;
32#
33# void main()
34# {
35#     // State of variables/expressions after "result += x;".
36#     //
37#     // i  x  i >> x  findLSB  findMSB  result
38#     // 0  0  0       -1       -1       0
39#     // 0  1  0       -1       -1       1
40#     // 1  0  1        0       -1       1
41#     // 1  1  0       -1       -1       2
42#
43#     int result = 0;
44#     for (int i = 0; i < 2; i++)
45#     {
46#         for (int x = 0; x < 2; x++)
47#         {
48#             // findMSB(findLSB(i >> x)) is always -1.
49#             for ( ; x > findMSB(findLSB(i >> x)) && x < 2; x++)
50#             {
51#                 result += x;
52#             }
53#         }
54#     }
55#     if (result == 2)
56#         _GLF_color = vec4(1, 0, 0, 1);
57#     else
58#         _GLF_color = vec4(0, 0, 0, 1);
59# }
60SHADER fragment variant_fragment_shader SPIRV-ASM TARGET_ENV spv1.0
61; SPIR-V
62; Version: 1.0
63; Generator: Khronos Glslang Reference Front End; 8
64; Bound: 66
65; Schema: 0
66               OpCapability Shader
67          %1 = OpExtInstImport "GLSL.std.450"
68               OpMemoryModel Logical GLSL450
69               OpEntryPoint Fragment %4 "main" %60
70               OpExecutionMode %4 OriginUpperLeft
71               OpSource ESSL 310
72               OpName %4 "main"
73               OpName %8 "result"
74               OpName %10 "i"
75               OpName %20 "x"
76               OpName %60 "_GLF_color"
77               OpDecorate %60 Location 0
78          %2 = OpTypeVoid
79          %3 = OpTypeFunction %2
80          %6 = OpTypeInt 32 1
81          %7 = OpTypePointer Function %6
82          %9 = OpConstant %6 0
83         %17 = OpConstant %6 2
84         %18 = OpTypeBool
85         %47 = OpConstant %6 1
86         %57 = OpTypeFloat 32
87         %58 = OpTypeVector %57 4
88         %59 = OpTypePointer Output %58
89         %60 = OpVariable %59 Output
90         %61 = OpConstant %57 1
91         %62 = OpConstant %57 0
92         %63 = OpConstantComposite %58 %61 %62 %62 %61
93         %65 = OpConstantComposite %58 %62 %62 %62 %61
94          %4 = OpFunction %2 None %3
95          %5 = OpLabel
96          %8 = OpVariable %7 Function
97         %10 = OpVariable %7 Function
98         %20 = OpVariable %7 Function
99               OpStore %8 %9
100               OpStore %10 %9
101               OpBranch %11
102         %11 = OpLabel
103               OpLoopMerge %13 %14 None
104               OpBranch %15
105         %15 = OpLabel
106         %16 = OpLoad %6 %10
107         %19 = OpSLessThan %18 %16 %17
108               OpBranchConditional %19 %12 %13
109         %12 = OpLabel
110               OpStore %20 %9
111               OpBranch %21
112         %21 = OpLabel
113               OpLoopMerge %23 %24 None
114               OpBranch %25
115         %25 = OpLabel
116         %26 = OpLoad %6 %20
117         %27 = OpSLessThan %18 %26 %17
118               OpBranchConditional %27 %22 %23
119         %22 = OpLabel
120               OpBranch %28
121         %28 = OpLabel
122               OpLoopMerge %30 %31 None
123               OpBranch %32
124         %32 = OpLabel
125         %33 = OpLoad %6 %20
126         %34 = OpLoad %6 %10
127         %35 = OpLoad %6 %20
128         %36 = OpShiftRightArithmetic %6 %34 %35
129         %37 = OpExtInst %6 %1 FindILsb %36
130         %38 = OpExtInst %6 %1 FindSMsb %37
131         %39 = OpSGreaterThan %18 %33 %38
132         %40 = OpLoad %6 %20
133         %41 = OpSLessThan %18 %40 %17
134         %42 = OpLogicalAnd %18 %39 %41
135               OpBranchConditional %42 %29 %30
136         %29 = OpLabel
137         %43 = OpLoad %6 %20
138         %44 = OpLoad %6 %8
139         %45 = OpIAdd %6 %44 %43
140               OpStore %8 %45
141               OpBranch %31
142         %31 = OpLabel
143         %46 = OpLoad %6 %20
144         %48 = OpIAdd %6 %46 %47
145               OpStore %20 %48
146               OpBranch %28
147         %30 = OpLabel
148               OpBranch %24
149         %24 = OpLabel
150         %49 = OpLoad %6 %20
151         %50 = OpIAdd %6 %49 %47
152               OpStore %20 %50
153               OpBranch %21
154         %23 = OpLabel
155               OpBranch %14
156         %14 = OpLabel
157         %51 = OpLoad %6 %10
158         %52 = OpIAdd %6 %51 %47
159               OpStore %10 %52
160               OpBranch %11
161         %13 = OpLabel
162         %53 = OpLoad %6 %8
163         %54 = OpIEqual %18 %53 %17
164               OpSelectionMerge %56 None
165               OpBranchConditional %54 %55 %64
166         %55 = OpLabel
167               OpStore %60 %63
168               OpBranch %56
169         %64 = OpLabel
170               OpStore %60 %65
171               OpBranch %56
172         %56 = OpLabel
173               OpReturn
174               OpFunctionEnd
175END
176
177
178BUFFER variant_framebuffer FORMAT B8G8R8A8_UNORM
179
180PIPELINE graphics variant_pipeline
181  ATTACH variant_vertex_shader
182  ATTACH variant_fragment_shader
183  FRAMEBUFFER_SIZE 256 256
184  BIND BUFFER variant_framebuffer AS color LOCATION 0
185END
186CLEAR_COLOR variant_pipeline 0 0 0 255
187
188CLEAR variant_pipeline
189RUN variant_pipeline DRAW_RECT POS 0 0 SIZE 256 256
190
191EXPECT variant_framebuffer IDX 0 0 SIZE 256 256 EQ_RGBA 255 0 0 255
192