6 files changed, 14 insertions, 1 deletions
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_nir.c b/src/gallium/auxiliary/gallivm/lp_bld_nir.c
index d69a5a4fb26..e13ec4e1a19 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_nir.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_nir.c
@@ -1149,6 +1149,7 @@ static void visit_intrinsic(struct lp_build_nir_context *bld_base,
    case nir_intrinsic_load_local_invocation_id:
    case nir_intrinsic_load_num_work_groups:
    case nir_intrinsic_load_invocation_id:
+   case nir_intrinsic_load_front_face:
       bld_base->sysval_intrin(bld_base, instr, result);
       break;
    case nir_intrinsic_discard_if:
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c b/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c
index 7ac96970116..5c3a40cdfea 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_nir_soa.c
@@ -943,6 +943,9 @@ static void emit_sysval_intrin(struct lp_build_nir_context *bld_base,
    case nir_intrinsic_load_invocation_id:
       result[0] = lp_build_broadcast_scalar(&bld_base->uint_bld, bld->system_values.invocation_id);
       break;
+   case nir_intrinsic_load_front_face:
+      result[0] = lp_build_broadcast_scalar(&bld_base->uint_bld, bld->system_values.front_facing);
+      break;
    default:
       break;
    }
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_tgsi.h b/src/gallium/auxiliary/gallivm/lp_bld_tgsi.h
index 6a67d90f8a5..7048fbc3325 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_tgsi.h
+++ b/src/gallium/auxiliary/gallivm/lp_bld_tgsi.h
@@ -173,6 +173,7 @@ struct lp_bld_tgsi_system_values {
    LLVMValueRef thread_id;
    LLVMValueRef block_id;
    LLVMValueRef grid_size;
+   LLVMValueRef front_facing;
 };
 
 
diff --git a/src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c b/src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c
index ca70a96302e..5ae3d51d986 100644
--- a/src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c
+++ b/src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c
@@ -1336,6 +1336,10 @@ emit_fetch_system_value(
       atype = TGSI_TYPE_UNSIGNED;
       break;
 
+   case TGSI_SEMANTIC_FACE:
+      res = lp_build_broadcast_scalar(&bld_base->uint_bld, bld->system_values.front_facing);
+      break;
+
    default:
       assert(!"unexpected semantic in emit_fetch_system_value");
       res = bld_base->base.zero;
diff --git a/src/gallium/drivers/llvmpipe/lp_screen.c b/src/gallium/drivers/llvmpipe/lp_screen.c
index 080b0635c64..0814145512c 100644
--- a/src/gallium/drivers/llvmpipe/lp_screen.c
+++ b/src/gallium/drivers/llvmpipe/lp_screen.c
@@ -337,7 +337,6 @@ llvmpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
    case PIPE_CAP_MULTI_DRAW_INDIRECT:
    case PIPE_CAP_MULTI_DRAW_INDIRECT_PARAMS:
    case PIPE_CAP_TGSI_FS_POSITION_IS_SYSVAL:
-   case PIPE_CAP_TGSI_FS_FACE_IS_INTEGER_SYSVAL:
    case PIPE_CAP_INVALIDATE_BUFFER:
    case PIPE_CAP_GENERATE_MIPMAP:
    case PIPE_CAP_STRING_MARKER:
@@ -392,6 +391,7 @@ llvmpipe_get_param(struct pipe_screen *screen, enum pipe_cap param)
       return LP_MAX_TGSI_SHADER_BUFFER_SIZE;
    case PIPE_CAP_FRAMEBUFFER_NO_ATTACHMENT:
    case PIPE_CAP_TGSI_TG4_COMPONENT_IN_SWIZZLE:
+   case PIPE_CAP_TGSI_FS_FACE_IS_INTEGER_SYSVAL:
       return 1;
    case PIPE_CAP_LOAD_CONSTBUF:
    case PIPE_CAP_PACKED_UNIFORMS:
diff --git a/src/gallium/drivers/llvmpipe/lp_state_fs.c b/src/gallium/drivers/llvmpipe/lp_state_fs.c
index d72c1a7498c..695ccb89682 100644
--- a/src/gallium/drivers/llvmpipe/lp_state_fs.c
+++ b/src/gallium/drivers/llvmpipe/lp_state_fs.c
@@ -342,6 +342,10 @@ generate_fs_loop(struct gallivm_state *gallivm,
 
    memset(&system_values, 0, sizeof(system_values));
 
+   /* truncate then sign extend. */
+   system_values.front_facing = LLVMBuildTrunc(gallivm->builder, facing, LLVMInt1TypeInContext(gallivm->context), "");
+   system_values.front_facing = LLVMBuildSExt(gallivm->builder, system_values.front_facing, LLVMInt32TypeInContext(gallivm->context), "");
+
    if (key->depth.enabled ||
        key->stencil[0].enabled) {