NVIDIA does not set the correct position of the buffer
AaronGhost opened this issue · 1 comments
AaronGhost commented
Description
The following code should affect the third value of the buffer but it affects the first value instead:
#version 310 es
layout(local_size_x = 1, local_size_y = 1, local_size_z = 1) in;
layout(std430, binding = 0) buffer buffer_0 {
int ext_2[3]; // 2 0 -2
int ext_3[1]; // -2147483648
} ;
int return_zero() //return 0
{
return 0;
}
void set_1(inout int A, int B) //set 1
{
return A = 1;
}
void main()
{
set_1(ext_2[clamp(~ext_3[0], 0, 2)], ext_3[return_zero()] += -2147483648);
}Nvidia output:
buffer_0 1 0 -2 0
Expected output:
buffer_0 2 0 1 0
Thinking process:
- set_1 affects one to the value on the left argument (a position in ext_2), the second parameter is unused.
- the position is given by clamp(~ext_3[0],0,2) where ext_3[0] = -2147483648
- ~ext_3[0] = 2147483647 so that clamp(~ext_3[0],0,2)=2
From what I understand from the OpenGL ES 3.1 specification (6.1.1 Function Calling Conventions), parameters should be evaluated from left to right, so that the side effect on the second parameter should have no effect to the position on the first parameter.
Code link
For the related code in the shadertrap test format, see: nvidia/miscompilation/shader02.shadertrap