gallium: remove PIPE_CAP_SHADER_CAN_READ_OUTPUTS

nir_lower_io_to_temporaries is now done for all stages except TCS, and
nir_lower_io_to_temporaries with a TCS is a no-op.

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Timothy Arceri <tarceri@itsqueeze.com>
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25590>

docs/gallium/screen.rst

@@ -413,8 +413,6 @@ The integer capabilities:
 * ``PIPE_CAP_STREAM_OUTPUT_INTERLEAVE_BUFFERS``: Whether interleaved stream
   output mode is able to interleave across buffers. This is required for
   :ext:`GL_ARB_transform_feedback3`.
-* ``PIPE_CAP_SHADER_CAN_READ_OUTPUTS``: Whether every TGSI shader stage can read
-  from the output file.
 * ``PIPE_CAP_FBFETCH``: The number of render targets whose value in the
   current framebuffer can be read in the shader.  0 means framebuffer fetch
   is not supported.  1 means that only the first render target can be read,

src/compiler/glsl/gl_nir_linker.c

@@ -1250,8 +1250,7 @@ preprocess_shader(const struct gl_constants *consts,
                  nir_shader_get_entrypoint(nir),
                  true, true);
    } else if (nir->info.stage == MESA_SHADER_TESS_EVAL ||
-              nir->info.stage == MESA_SHADER_FRAGMENT ||
+              nir->info.stage == MESA_SHADER_FRAGMENT) {
-              !consts->SupportsReadingOutputs) {
       NIR_PASS(_, nir, nir_lower_io_to_temporaries,
                  nir_shader_get_entrypoint(nir),
                  true, false);

src/gallium/auxiliary/util/u_screen.c

@@ -314,7 +314,6 @@ u_pipe_screen_get_param_defaults(struct pipe_screen *pscreen,
    case PIPE_CAP_MIXED_COLOR_DEPTH_BITS:
    case PIPE_CAP_SHADER_ARRAY_COMPONENTS:
    case PIPE_CAP_STREAM_OUTPUT_INTERLEAVE_BUFFERS:
-   case PIPE_CAP_SHADER_CAN_READ_OUTPUTS:
    case PIPE_CAP_NATIVE_FENCE_FD:
       return 0;
 

src/gallium/drivers/nouveau/nv30/nv30_screen.c

@@ -214,7 +214,6 @@ nv30_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_VIEWPORT_SUBPIXEL_BITS:
    case PIPE_CAP_MIXED_COLOR_DEPTH_BITS:
    case PIPE_CAP_SHADER_ARRAY_COMPONENTS:
-   case PIPE_CAP_SHADER_CAN_READ_OUTPUTS:
    case PIPE_CAP_NATIVE_FENCE_FD:
    case PIPE_CAP_FBFETCH:
    case PIPE_CAP_LEGACY_MATH_RULES:

src/gallium/drivers/radeonsi/si_get.c

@@ -139,7 +139,6 @@ static int si_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_STRING_MARKER:
    case PIPE_CAP_CULL_DISTANCE:
    case PIPE_CAP_SHADER_ARRAY_COMPONENTS:
-   case PIPE_CAP_SHADER_CAN_READ_OUTPUTS:
    case PIPE_CAP_STREAM_OUTPUT_PAUSE_RESUME:
    case PIPE_CAP_STREAM_OUTPUT_INTERLEAVE_BUFFERS:
    case PIPE_CAP_DOUBLES:

src/gallium/drivers/v3d/v3d_screen.c

@@ -140,7 +140,6 @@ v3d_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
         case PIPE_CAP_MULTI_DRAW_INDIRECT:
         case PIPE_CAP_QUADS_FOLLOW_PROVOKING_VERTEX_CONVENTION:
         case PIPE_CAP_SIGNED_VERTEX_BUFFER_OFFSET:
-        case PIPE_CAP_SHADER_CAN_READ_OUTPUTS:
         case PIPE_CAP_SHADER_PACK_HALF_FLOAT:
         case PIPE_CAP_TEXTURE_HALF_FLOAT_LINEAR:
         case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:

src/gallium/include/pipe/p_defines.h

@@ -819,7 +819,6 @@ enum pipe_cap
    PIPE_CAP_MIXED_COLOR_DEPTH_BITS,
    PIPE_CAP_SHADER_ARRAY_COMPONENTS,
    PIPE_CAP_STREAM_OUTPUT_INTERLEAVE_BUFFERS,
-   PIPE_CAP_SHADER_CAN_READ_OUTPUTS,
    PIPE_CAP_NATIVE_FENCE_FD,
    PIPE_CAP_GLSL_TESS_LEVELS_AS_INPUTS,
    PIPE_CAP_FBFETCH,

src/mesa/main/consts_exts.h

@@ -954,9 +954,6 @@ struct gl_constants
 
    bool HasFBFetch;
 
-   /** Whether the backend supports reading from outputs */
-   bool SupportsReadingOutputs;
-
    bool CombinedClipCullDistanceArrays;
 
    bool PointSizeFixed;

src/mesa/state_tracker/st_extensions.c

@@ -170,8 +170,6 @@ void st_init_limits(struct pipe_screen *screen,
 
    c->HasFBFetch = screen->get_param(screen, PIPE_CAP_FBFETCH);
 
-   c->SupportsReadingOutputs = screen->get_param(screen, PIPE_CAP_SHADER_CAN_READ_OUTPUTS);
-
    c->CombinedClipCullDistanceArrays = !screen->get_param(screen, PIPE_CAP_CULL_DISTANCE_NOCOMBINE);
 
    c->PointSizeFixed = screen->get_param(screen, PIPE_CAP_POINT_SIZE_FIXED) != PIPE_POINT_SIZE_LOWER_ALWAYS;