gallium: add opcodes/cap for fine derivative support

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Marek Olšák <marek.olsak@amd.com> (v1)
Reviewed-by: Roland Scheidegger <sroland@vmware.com> (v1)
v2: Reuse opcode gaps as suggested by Marek

src/gallium/auxiliary/tgsi/tgsi_info.c

@@ -116,8 +116,8 @@ static const struct tgsi_opcode_info opcode_info[TGSI_OPCODE_LAST] =
    { 0, 1, 0, 0, 0, 1, NONE, "", 76 },      /* removed */
    { 0, 0, 0, 1, 1, 1, NONE, "ELSE", TGSI_OPCODE_ELSE },
    { 0, 0, 0, 0, 1, 0, NONE, "ENDIF", TGSI_OPCODE_ENDIF },
-   { 1, 0, 0, 0, 1, 0, NONE, "", 79 },      /* removed */
-   { 0, 0, 0, 0, 1, 0, NONE, "", 80 },      /* removed */
+   { 1, 1, 0, 0, 0, 0, COMP, "DDX_FINE", TGSI_OPCODE_DDX_FINE },
+   { 1, 1, 0, 0, 0, 0, COMP, "DDY_FINE", TGSI_OPCODE_DDY_FINE },
    { 0, 1, 0, 0, 0, 0, NONE, "PUSHA", TGSI_OPCODE_PUSHA },
    { 1, 0, 0, 0, 0, 0, NONE, "POPA", TGSI_OPCODE_POPA },
    { 1, 1, 0, 0, 0, 0, COMP, "CEIL", TGSI_OPCODE_CEIL },

src/gallium/auxiliary/tgsi/tgsi_util.c

@@ -245,6 +245,8 @@ tgsi_util_get_inst_usage_mask(const struct tgsi_full_instruction *inst,
    case TGSI_OPCODE_USNE:
    case TGSI_OPCODE_IMUL_HI:
    case TGSI_OPCODE_UMUL_HI:
+   case TGSI_OPCODE_DDX_FINE:
+   case TGSI_OPCODE_DDY_FINE:
       /* Channel-wise operations */
       read_mask = write_mask;
       break;

src/gallium/docs/source/screen.rst

@@ -213,6 +213,8 @@ The integer capabilities:
 * ``PIPE_CAP_DRAW_INDIRECT``: Whether the driver supports taking draw arguments
   { count, instance_count, start, index_bias } from a PIPE_BUFFER resource.
   See pipe_draw_info.
+* ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE``: Whether the fragment shader supports
+  the FINE versions of DDX/DDY.
 
 
 .. _pipe_capf:

src/gallium/docs/source/tgsi.rst

@@ -433,7 +433,11 @@ This instruction replicates its result.
   dst = \cos{src.x}
 
 
-.. opcode:: DDX - Derivative Relative To X
+.. opcode:: DDX, DDX_FINE - Derivative Relative To X
+
+The fine variant is only used when ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE`` is
+advertised. When it is, the fine version guarantees one derivative per row
+while DDX is allowed to be the same for the entire 2x2 quad.
 
 .. math::
 
@@ -446,7 +450,11 @@ This instruction replicates its result.
   dst.w = partialx(src.w)
 
 
-.. opcode:: DDY - Derivative Relative To Y
+.. opcode:: DDY, DDY_FINE - Derivative Relative To Y
+
+The fine variant is only used when ``PIPE_CAP_TGSI_FS_FINE_DERIVATIVE`` is
+advertised. When it is, the fine version guarantees one derivative per column
+while DDY is allowed to be the same for the entire 2x2 quad.
 
 .. math::
 

src/gallium/drivers/freedreno/freedreno_screen.c

@@ -216,6 +216,7 @@ fd_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
 	case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
 	case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
 	case PIPE_CAP_DRAW_INDIRECT:
+	case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
 		return 0;
 
 	/* Stream output. */

src/gallium/drivers/i915/i915_screen.c

@@ -231,6 +231,7 @@ i915_get_param(struct pipe_screen *screen, enum pipe_cap cap)
    case PIPE_CAP_TGSI_VS_LAYER_VIEWPORT:
    case PIPE_CAP_BUFFER_MAP_PERSISTENT_COHERENT:
    case PIPE_CAP_DRAW_INDIRECT:
+   case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
       return 0;
 
    case PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT:

src/gallium/drivers/ilo/ilo_screen.c

@@ -433,6 +433,7 @@ ilo_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
    case PIPE_CAP_MAX_VERTEX_STREAMS:
    case PIPE_CAP_DRAW_INDIRECT:
+   case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
       return 0;
 
    default:

src/gallium/drivers/llvmpipe/lp_screen.c

@@ -248,6 +248,7 @@ llvmpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_SAMPLE_SHADING:
    case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
    case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
+   case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
       return 0;
    case PIPE_CAP_FAKE_SW_MSAA:
       return 1;

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

@@ -148,6 +148,7 @@ nv30_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_USER_VERTEX_BUFFERS:
    case PIPE_CAP_COMPUTE:
    case PIPE_CAP_DRAW_INDIRECT:
+   case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
       return 0;
    }
 

src/gallium/drivers/nouveau/nv50/nv50_screen.c

@@ -200,6 +200,7 @@ nv50_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
    case PIPE_CAP_COMPUTE:
    case PIPE_CAP_DRAW_INDIRECT:
+   case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
       return 0;
    }
 

src/gallium/drivers/nouveau/nvc0/nvc0_screen.c

@@ -184,6 +184,7 @@ nvc0_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_TGSI_VS_LAYER_VIEWPORT:
    case PIPE_CAP_FAKE_SW_MSAA:
    case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
+   case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
       return 0;
    }
 

src/gallium/drivers/r300/r300_screen.c

@@ -178,6 +178,7 @@ static int r300_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
         case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
         case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
         case PIPE_CAP_DRAW_INDIRECT:
+        case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
             return 0;
 
         /* SWTCL-only features. */

src/gallium/drivers/r600/r600_pipe.c

@@ -319,6 +319,7 @@ static int r600_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
 	case PIPE_CAP_SAMPLE_SHADING:
 	case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
 	case PIPE_CAP_DRAW_INDIRECT:
+	case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
 		return 0;
 
 	/* Stream output. */

src/gallium/drivers/radeonsi/si_pipe.c

@@ -254,6 +254,7 @@ static int si_get_param(struct pipe_screen* pscreen, enum pipe_cap param)
 	case PIPE_CAP_FAKE_SW_MSAA:
 	case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
 	case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
+	case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
 		return 0;
 
 	case PIPE_CAP_TEXTURE_BORDER_COLOR_QUIRK:

src/gallium/drivers/softpipe/sp_screen.c

@@ -194,6 +194,7 @@ softpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_SAMPLE_SHADING:
    case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
    case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
+   case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
       return 0;
    case PIPE_CAP_FAKE_SW_MSAA:
       return 1;

src/gallium/drivers/svga/svga_screen.c

@@ -278,6 +278,7 @@ svga_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_TEXTURE_GATHER_OFFSETS:
    case PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION:
    case PIPE_CAP_DRAW_INDIRECT:
+   case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
       return 0;
    case PIPE_CAP_MIN_MAP_BUFFER_ALIGNMENT:
       return 64;

src/gallium/drivers/vc4/vc4_screen.c

@@ -157,6 +157,7 @@ vc4_screen_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
         case PIPE_CAP_MAX_TEXEL_OFFSET:
         case PIPE_CAP_MAX_VERTEX_STREAMS:
         case PIPE_CAP_DRAW_INDIRECT:
+        case PIPE_CAP_TGSI_FS_FINE_DERIVATIVE:
                 return 0;
 
                 /* Stream output. */

src/gallium/include/pipe/p_defines.h

@@ -562,6 +562,7 @@ enum pipe_cap {
    PIPE_CAP_TGSI_VS_WINDOW_SPACE_POSITION = 99,
    PIPE_CAP_MAX_VERTEX_STREAMS = 100,
    PIPE_CAP_DRAW_INDIRECT = 101,
+   PIPE_CAP_TGSI_FS_FINE_DERIVATIVE = 102,
 };
 
 #define PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_NV50 (1 << 0)

src/gallium/include/pipe/p_shader_tokens.h

@@ -352,7 +352,10 @@ struct tgsi_property_data {
 #define TGSI_OPCODE_UIF                 75
 #define TGSI_OPCODE_ELSE                77
 #define TGSI_OPCODE_ENDIF               78
-                                /* gap */
+
+#define TGSI_OPCODE_DDX_FINE            79
+#define TGSI_OPCODE_DDY_FINE            80
+
 #define TGSI_OPCODE_PUSHA               81
 #define TGSI_OPCODE_POPA                82
 #define TGSI_OPCODE_CEIL                83