radeonsi: workaround for gather4 on integer cube maps

This is the same workaround that radv already applied in commit
3ece76f03dc0 ("radv/ac: gather4 cube workaround integer").

Fixes dEQP-GLES31.functional.texture.gather.basic.cube.rgba8i/ui.*

Cc: mesa-stable@lists.freedesktop.org
Reviewed-by: Marek Olšák <marek.olsak@amd.com>

diff --git a/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c b/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c
index a590ea607b59a0ac0f5278d7eead5722c4b76394..a37fe586d6f8bc4202b7f2566f4232afd51fbc2c 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c
+++ b/src/gallium/drivers/radeonsi/si_shader_tgsi_mem.c
@@ -1685,10 +1685,18 @@ static void tex_fetch_args(
  *
  * The workaround is to subtract 0.5 from the unnormalized coordinates,
  * or (0.5 / size) from the normalized coordinates.
+ *
+ * However, cube textures with 8_8_8_8 data formats require a different
+ * workaround of overriding the num format to USCALED/SSCALED. This would lose
+ * precision in 32-bit data formats, so it needs to be applied dynamically at
+ * runtime. In this case, return an i1 value that indicates whether the
+ * descriptor was overridden (and hence a fixup of the sampler result is needed).
  */
-static void si_lower_gather4_integer(struct si_shader_context *ctx,
-                                    struct ac_image_args *args,
-                                    unsigned target)
+static LLVMValueRef
+si_lower_gather4_integer(struct si_shader_context *ctx,
+                        struct ac_image_args *args,
+                        unsigned target,
+                        enum tgsi_return_type return_type)
 {
        LLVMBuilderRef builder = ctx->gallivm.builder;
        LLVMValueRef coord = args->addr;
@@ -1700,6 +1708,43 @@ static void si_lower_gather4_integer(struct si_shader_context *ctx,
        unsigned coord_vgpr_index = (int)args->offset + (int)args->compare;
        int c;
 
+       assert(return_type == TGSI_RETURN_TYPE_SINT ||
+              return_type == TGSI_RETURN_TYPE_UINT);
+
+       if (target == TGSI_TEXTURE_CUBE ||
+           target == TGSI_TEXTURE_CUBE_ARRAY) {
+               LLVMValueRef formats;
+               LLVMValueRef data_format;
+               LLVMValueRef wa_formats;
+               LLVMValueRef wa;
+
+               formats = LLVMBuildExtractElement(builder, args->resource, ctx->i32_1, "");
+
+               data_format = LLVMBuildLShr(builder, formats,
+                                           LLVMConstInt(ctx->i32, 20, false), "");
+               data_format = LLVMBuildAnd(builder, data_format,
+                                          LLVMConstInt(ctx->i32, (1u << 6) - 1, false), "");
+               wa = LLVMBuildICmp(builder, LLVMIntEQ, data_format,
+                                  LLVMConstInt(ctx->i32, V_008F14_IMG_DATA_FORMAT_8_8_8_8, false),
+                                  "");
+
+               uint32_t wa_num_format =
+                       return_type == TGSI_RETURN_TYPE_UINT ?
+                       S_008F14_NUM_FORMAT_GFX6(V_008F14_IMG_NUM_FORMAT_USCALED) :
+                       S_008F14_NUM_FORMAT_GFX6(V_008F14_IMG_NUM_FORMAT_SSCALED);
+               wa_formats = LLVMBuildAnd(builder, formats,
+                                         LLVMConstInt(ctx->i32, C_008F14_NUM_FORMAT_GFX6, false),
+                                         "");
+               wa_formats = LLVMBuildOr(builder, wa_formats,
+                                       LLVMConstInt(ctx->i32, wa_num_format, false), "");
+
+               formats = LLVMBuildSelect(builder, wa, wa_formats, formats, "");
+               args->resource = LLVMBuildInsertElement(
+                       builder, args->resource, formats, ctx->i32_1, "");
+
+               return wa;
+       }
+
        if (target == TGSI_TEXTURE_RECT ||
            target == TGSI_TEXTURE_SHADOWRECT) {
                half_texel[0] = half_texel[1] = LLVMConstReal(ctx->f32, -0.5);
@@ -1742,6 +1787,42 @@ static void si_lower_gather4_integer(struct si_shader_context *ctx,
        }
 
        args->addr = coord;
+
+       return NULL;
+}
+
+/* The second half of the cube texture 8_8_8_8 integer workaround: adjust the
+ * result after the gather operation.
+ */
+static LLVMValueRef
+si_fix_gather4_integer_result(struct si_shader_context *ctx,
+                          LLVMValueRef result,
+                          enum tgsi_return_type return_type,
+                          LLVMValueRef wa)
+{
+       LLVMBuilderRef builder = ctx->gallivm.builder;
+
+       assert(return_type == TGSI_RETURN_TYPE_SINT ||
+              return_type == TGSI_RETURN_TYPE_UINT);
+
+       for (unsigned chan = 0; chan < 4; ++chan) {
+               LLVMValueRef chanv = LLVMConstInt(ctx->i32, chan, false);
+               LLVMValueRef value;
+               LLVMValueRef wa_value;
+
+               value = LLVMBuildExtractElement(builder, result, chanv, "");
+
+               if (return_type == TGSI_RETURN_TYPE_UINT)
+                       wa_value = LLVMBuildFPToUI(builder, value, ctx->i32, "");
+               else
+                       wa_value = LLVMBuildFPToSI(builder, value, ctx->i32, "");
+               wa_value = LLVMBuildBitCast(builder, wa_value, ctx->f32, "");
+               value = LLVMBuildSelect(builder, wa, wa_value, value, "");
+
+               result = LLVMBuildInsertElement(builder, result, value, chanv, "");
+       }
+
+       return result;
 }
 
 static void build_tex_intrinsic(const struct lp_build_tgsi_action *action,
@@ -1816,17 +1897,30 @@ static void build_tex_intrinsic(const struct lp_build_tgsi_action *action,
        }
 
        /* The hardware needs special lowering for Gather4 with integer formats. */
+       LLVMValueRef gather4_int_result_workaround = NULL;
+
        if (ctx->screen->b.chip_class <= VI &&
            opcode == TGSI_OPCODE_TG4) {
                assert(inst->Texture.ReturnType != TGSI_RETURN_TYPE_UNKNOWN);
 
                if (inst->Texture.ReturnType == TGSI_RETURN_TYPE_SINT ||
-                   inst->Texture.ReturnType == TGSI_RETURN_TYPE_UINT)
-                       si_lower_gather4_integer(ctx, &args, target);
+                   inst->Texture.ReturnType == TGSI_RETURN_TYPE_UINT) {
+                       gather4_int_result_workaround =
+                               si_lower_gather4_integer(ctx, &args, target,
+                                                        inst->Texture.ReturnType);
+               }
        }
 
-       emit_data->output[emit_data->chan] =
+       LLVMValueRef result =
                ac_build_image_opcode(&ctx->ac, &args);
+
+       if (gather4_int_result_workaround) {
+               result = si_fix_gather4_integer_result(ctx, result,
+                                                      inst->Texture.ReturnType,
+                                                      gather4_int_result_workaround);
+       }
+
+       emit_data->output[emit_data->chan] = result;
 }
 
 static void si_llvm_emit_txqs(