gallium: add a cap to enable double rounding opcodes

Signed-off-by: Ilia Mirkin <imirkin@alum.mit.edu>
Reviewed-by: Dave Airlie <airlied@redhat.com>

src/gallium/auxiliary/gallivm/lp_bld_limits.h

@@ -127,6 +127,7 @@ gallivm_get_shader_param(enum pipe_shader_cap param)
    case PIPE_SHADER_CAP_TGSI_SQRT_SUPPORTED:
       return 1;
    case PIPE_SHADER_CAP_DOUBLES:
+   case PIPE_SHADER_CAP_TGSI_DROUND_SUPPORTED:
       return 0;
    }
    /* if we get here, we missed a shader cap above (and should have seen

src/gallium/auxiliary/tgsi/tgsi_exec.h

@@ -457,6 +457,8 @@ tgsi_exec_get_shader_param(enum pipe_shader_cap param)
       return 1;
    case PIPE_SHADER_CAP_DOUBLES:
       return 1;
+   case PIPE_SHADER_CAP_TGSI_DROUND_SUPPORTED:
+      return 0;
    }
    /* if we get here, we missed a shader cap above (and should have seen
     * a compiler warning.)

src/gallium/docs/source/screen.rst

@@ -332,6 +332,8 @@ to be 0.
   sampler views. Must not be lower than PIPE_SHADER_CAP_MAX_TEXTURE_SAMPLERS.
 * ``PIPE_SHADER_CAP_DOUBLES``: Whether double precision floating-point
   operations are supported.
+* ``PIPE_SHADER_CAP_TGSI_DROUND_SUPPORTED``: Whether double precision rounding
+  is supported. If it is, DTRUNC/DCEIL/DFLR/DROUND opcodes may be used.
 
 
 .. _pipe_compute_cap:

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

@@ -290,6 +290,10 @@ nvc0_screen_get_shader_param(struct pipe_screen *pscreen, unsigned shader,
       return 1;
    case PIPE_SHADER_CAP_INTEGERS:
       return 1;
+   case PIPE_SHADER_CAP_DOUBLES:
+      return 0;
+   case PIPE_SHADER_CAP_TGSI_DROUND_SUPPORTED:
+      return 0;
    case PIPE_SHADER_CAP_MAX_TEXTURE_SAMPLERS:
       return 16; /* would be 32 in linked (OpenGL-style) mode */
    case PIPE_SHADER_CAP_MAX_SAMPLER_VIEWS:

src/gallium/drivers/r600/r600_pipe.c

@@ -489,6 +489,8 @@ static int r600_get_shader_param(struct pipe_screen* pscreen, unsigned shader, e
 		}
 	case PIPE_SHADER_CAP_DOUBLES:
 		return 0;
+	case PIPE_SHADER_CAP_TGSI_DROUND_SUPPORTED:
+		return 0;
 	}
 	return 0;
 }

src/gallium/drivers/radeonsi/si_pipe.c

@@ -423,6 +423,7 @@ static int si_get_shader_param(struct pipe_screen* pscreen, unsigned shader, enu
 	case PIPE_SHADER_CAP_PREFERRED_IR:
 		return PIPE_SHADER_IR_TGSI;
 	case PIPE_SHADER_CAP_DOUBLES:
+	case PIPE_SHADER_CAP_TGSI_DROUND_SUPPORTED:
 		return 0;
 	}
 	return 0;

src/gallium/drivers/svga/svga_screen.c

@@ -373,6 +373,7 @@ static int svga_get_shader_param(struct pipe_screen *screen, unsigned shader, en
       case PIPE_SHADER_CAP_PREFERRED_IR:
          return PIPE_SHADER_IR_TGSI;
       case PIPE_SHADER_CAP_DOUBLES:
+      case PIPE_SHADER_CAP_TGSI_DROUND_SUPPORTED:
          return 0;
       }
       /* If we get here, we failed to handle a cap above */

src/gallium/include/pipe/p_defines.h

@@ -635,7 +635,8 @@ enum pipe_shader_cap
    PIPE_SHADER_CAP_PREFERRED_IR,
    PIPE_SHADER_CAP_TGSI_SQRT_SUPPORTED,
    PIPE_SHADER_CAP_MAX_SAMPLER_VIEWS,
-   PIPE_SHADER_CAP_DOUBLES
+   PIPE_SHADER_CAP_DOUBLES,
+   PIPE_SHADER_CAP_TGSI_DROUND_SUPPORTED, /* all rounding modes */
 };
 
 /**