diff options
Diffstat (limited to 'src/intel')
| -rw-r--r-- | src/intel/compiler/brw_fs_reg_allocate.cpp | 112 |
1 files changed, 50 insertions, 62 deletions
diff --git a/src/intel/compiler/brw_fs_reg_allocate.cpp b/src/intel/compiler/brw_fs_reg_allocate.cpp index 14a110c326b..447f49f30a2 100644 --- a/src/intel/compiler/brw_fs_reg_allocate.cpp +++ b/src/intel/compiler/brw_fs_reg_allocate.cpp @@ -415,7 +415,7 @@ private: int first_payload_node); void setup_mrf_hack_interference(int first_mrf_node, int *first_used_mrf); - void build_interference_graph(); + void build_interference_graph(bool allow_spilling); int choose_spill_reg(); void spill_reg(unsigned spill_reg); @@ -530,6 +530,47 @@ get_used_mrfs(fs_visitor *v, bool *mrf_used) } } +namespace { + /** + * Maximum spill block size we expect to encounter in 32B units. + * + * This is somewhat arbitrary and doesn't necessarily limit the maximum + * variable size that can be spilled -- A higher value will allow a + * variable of a given size to be spilled more efficiently with a smaller + * number of scratch messages, but will increase the likelihood of a + * collision between the MRFs reserved for spilling and other MRFs used by + * the program (and possibly increase GRF register pressure on platforms + * without hardware MRFs), what could cause register allocation to fail. + * + * For the moment reserve just enough space so a register of 32 bit + * component type and natural region width can be spilled without splitting + * into multiple (force_writemask_all) scratch messages. + */ + unsigned + spill_max_size(const backend_shader *s) + { + /* FINISHME - On Gen7+ it should be possible to avoid this limit + * altogether by spilling directly from the temporary GRF + * allocated to hold the result of the instruction (and the + * scratch write header). + */ + /* FINISHME - The shader's dispatch width probably belongs in + * backend_shader (or some nonexistent fs_shader class?) + * rather than in the visitor class. + */ + return static_cast<const fs_visitor *>(s)->dispatch_width / 8; + } + + /** + * First MRF register available for spilling. + */ + unsigned + spill_base_mrf(const backend_shader *s) + { + return BRW_MAX_MRF(s->devinfo->gen) - spill_max_size(s) - 1; + } +} + /** * Sets interference between virtual GRFs and usage of the high GRFs for SEND * messages (treated as MRFs in code generation). @@ -538,11 +579,8 @@ void fs_reg_alloc::setup_mrf_hack_interference(int first_mrf_node, int *first_used_mrf) { - bool mrf_used[BRW_MAX_MRF(fs->devinfo->gen)]; - get_used_mrfs(fs, mrf_used); - - *first_used_mrf = BRW_MAX_MRF(devinfo->gen); - for (int i = 0; i < BRW_MAX_MRF(devinfo->gen); i++) { + *first_used_mrf = spill_base_mrf(fs); + for (int i = spill_base_mrf(fs); i < BRW_MAX_MRF(devinfo->gen); i++) { /* Mark each MRF reg node as being allocated to its physical register. * * The alternative would be to have per-physical-register classes, which @@ -550,22 +588,13 @@ fs_reg_alloc::setup_mrf_hack_interference(int first_mrf_node, */ ra_set_node_reg(g, first_mrf_node + i, GEN7_MRF_HACK_START + i); - /* Since we don't have any live/dead analysis on the MRFs, just mark all - * that are used as conflicting with all virtual GRFs. - */ - if (mrf_used[i]) { - if (i < *first_used_mrf) - *first_used_mrf = i; - - for (unsigned j = 0; j < fs->alloc.count; j++) { - ra_add_node_interference(g, first_mrf_node + i, j); - } - } + for (unsigned j = 0; j < fs->alloc.count; j++) + ra_add_node_interference(g, first_mrf_node + i, j); } } void -fs_reg_alloc::build_interference_graph() +fs_reg_alloc::build_interference_graph(bool allow_spilling) { const gen_device_info *devinfo = fs->devinfo; const brw_compiler *compiler = fs->compiler; @@ -643,8 +672,8 @@ fs_reg_alloc::build_interference_graph() setup_payload_interference(payload_node_count, first_payload_node); if (devinfo->gen >= 7) { int first_used_mrf = BRW_MAX_MRF(devinfo->gen); - setup_mrf_hack_interference(first_mrf_hack_node, - &first_used_mrf); + if (allow_spilling) + setup_mrf_hack_interference(first_mrf_hack_node, &first_used_mrf); foreach_block_and_inst(block, fs_inst, inst, fs->cfg) { /* When we do send-from-GRF for FB writes, we need to ensure that @@ -758,47 +787,6 @@ fs_reg_alloc::build_interference_graph() } } -namespace { - /** - * Maximum spill block size we expect to encounter in 32B units. - * - * This is somewhat arbitrary and doesn't necessarily limit the maximum - * variable size that can be spilled -- A higher value will allow a - * variable of a given size to be spilled more efficiently with a smaller - * number of scratch messages, but will increase the likelihood of a - * collision between the MRFs reserved for spilling and other MRFs used by - * the program (and possibly increase GRF register pressure on platforms - * without hardware MRFs), what could cause register allocation to fail. - * - * For the moment reserve just enough space so a register of 32 bit - * component type and natural region width can be spilled without splitting - * into multiple (force_writemask_all) scratch messages. - */ - unsigned - spill_max_size(const backend_shader *s) - { - /* FINISHME - On Gen7+ it should be possible to avoid this limit - * altogether by spilling directly from the temporary GRF - * allocated to hold the result of the instruction (and the - * scratch write header). - */ - /* FINISHME - The shader's dispatch width probably belongs in - * backend_shader (or some nonexistent fs_shader class?) - * rather than in the visitor class. - */ - return static_cast<const fs_visitor *>(s)->dispatch_width / 8; - } - - /** - * First MRF register available for spilling. - */ - unsigned - spill_base_mrf(const backend_shader *s) - { - return BRW_MAX_MRF(s->devinfo->gen) - spill_max_size(s) - 1; - } -} - static void emit_unspill(const fs_builder &bld, fs_reg dst, uint32_t spill_offset, unsigned count) @@ -1063,7 +1051,7 @@ fs_reg_alloc::spill_reg(unsigned spill_reg) bool fs_reg_alloc::assign_regs(bool allow_spilling, bool spill_all) { - build_interference_graph(); + build_interference_graph(fs->spilled_any_registers); /* Debug of register spilling: Go spill everything. */ if (unlikely(spill_all)) { |