Module: Mesa Branch: master Commit: 755a2907a3e7f896f86861254554543d815bfad3 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=755a2907a3e7f896f86861254554543d815bfad3
Author: Marek Olšák <[email protected]> Date: Sat Feb 28 14:01:43 2015 +0100 radeonsi: implement bit-finding opcodes from ARB_gpu_shader5 Reviewed-by: Glenn Kennard <[email protected]> --- .../drivers/radeon/radeon_setup_tgsi_llvm.c | 92 ++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c index 385d3ad..47c9d0c 100644 --- a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c +++ b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c @@ -1234,6 +1234,95 @@ build_tgsi_intrinsic_nomem( build_tgsi_intrinsic(action, bld_base, emit_data, LLVMReadNoneAttribute); } +/* this is ffs in C */ +static void emit_lsb(const struct lp_build_tgsi_action * action, + struct lp_build_tgsi_context * bld_base, + struct lp_build_emit_data * emit_data) +{ + struct gallivm_state *gallivm = bld_base->base.gallivm; + LLVMValueRef args[2] = { + emit_data->args[0], + + /* The value of 1 means that ffs(x=0) = undef, so LLVM won't + * add special code to check for x=0. The reason is that + * the LLVM behavior for x=0 is different from what we + * need here. + * + * The hardware already implements the correct behavior. + */ + lp_build_const_int32(gallivm, 1) + }; + + emit_data->output[emit_data->chan] = + build_intrinsic(gallivm->builder, "llvm.cttz.i32", + emit_data->dst_type, args, Elements(args), + LLVMReadNoneAttribute); +} + +/* Find the last bit set. */ +static void emit_umsb(const struct lp_build_tgsi_action * action, + struct lp_build_tgsi_context * bld_base, + struct lp_build_emit_data * emit_data) +{ + struct gallivm_state *gallivm = bld_base->base.gallivm; + LLVMBuilderRef builder = gallivm->builder; + LLVMValueRef args[2] = { + emit_data->args[0], + /* Don't generate code for handling zero: */ + lp_build_const_int32(gallivm, 1) + }; + + LLVMValueRef msb = + build_intrinsic(builder, "llvm.ctlz.i32", + emit_data->dst_type, args, Elements(args), + LLVMReadNoneAttribute); + + /* The HW returns the last bit index from MSB, but TGSI wants + * the index from LSB. Invert it by doing "31 - msb". */ + msb = LLVMBuildSub(builder, lp_build_const_int32(gallivm, 31), + msb, ""); + + /* Check for zero: */ + emit_data->output[emit_data->chan] = + LLVMBuildSelect(builder, + LLVMBuildICmp(builder, LLVMIntEQ, args[0], + bld_base->uint_bld.zero, ""), + lp_build_const_int32(gallivm, -1), msb, ""); +} + +/* Find the last bit opposite of the sign bit. */ +static void emit_imsb(const struct lp_build_tgsi_action * action, + struct lp_build_tgsi_context * bld_base, + struct lp_build_emit_data * emit_data) +{ + struct gallivm_state *gallivm = bld_base->base.gallivm; + LLVMBuilderRef builder = gallivm->builder; + LLVMValueRef arg = emit_data->args[0]; + + LLVMValueRef msb = + build_intrinsic(builder, "llvm.AMDGPU.flbit.i32", + emit_data->dst_type, &arg, 1, + LLVMReadNoneAttribute); + + /* The HW returns the last bit index from MSB, but TGSI wants + * the index from LSB. Invert it by doing "31 - msb". */ + msb = LLVMBuildSub(builder, lp_build_const_int32(gallivm, 31), + msb, ""); + + /* If arg == 0 || arg == -1 (0xffffffff), return -1. */ + LLVMValueRef all_ones = lp_build_const_int32(gallivm, -1); + + LLVMValueRef cond = + LLVMBuildOr(builder, + LLVMBuildICmp(builder, LLVMIntEQ, arg, + bld_base->uint_bld.zero, ""), + LLVMBuildICmp(builder, LLVMIntEQ, arg, + all_ones, ""), ""); + + emit_data->output[emit_data->chan] = + LLVMBuildSelect(builder, cond, all_ones, msb, ""); +} + void radeon_llvm_context_init(struct radeon_llvm_context * ctx) { struct lp_type type; @@ -1333,6 +1422,7 @@ void radeon_llvm_context_init(struct radeon_llvm_context * ctx) bld_base->op_actions[TGSI_OPCODE_IMAX].intr_name = "llvm.AMDGPU.imax"; bld_base->op_actions[TGSI_OPCODE_IMIN].emit = build_tgsi_intrinsic_nomem; bld_base->op_actions[TGSI_OPCODE_IMIN].intr_name = "llvm.AMDGPU.imin"; + bld_base->op_actions[TGSI_OPCODE_IMSB].emit = emit_imsb; bld_base->op_actions[TGSI_OPCODE_INEG].emit = emit_ineg; bld_base->op_actions[TGSI_OPCODE_ISHR].emit = emit_ishr; bld_base->op_actions[TGSI_OPCODE_ISGE].emit = emit_icmp; @@ -1343,11 +1433,13 @@ void radeon_llvm_context_init(struct radeon_llvm_context * ctx) bld_base->op_actions[TGSI_OPCODE_KILL_IF].intr_name = "llvm.AMDGPU.kill"; bld_base->op_actions[TGSI_OPCODE_KILL].emit = lp_build_tgsi_intrinsic; bld_base->op_actions[TGSI_OPCODE_KILL].intr_name = "llvm.AMDGPU.kilp"; + bld_base->op_actions[TGSI_OPCODE_LSB].emit = emit_lsb; bld_base->op_actions[TGSI_OPCODE_LG2].emit = build_tgsi_intrinsic_nomem; bld_base->op_actions[TGSI_OPCODE_LG2].intr_name = "llvm.log2.f32"; bld_base->op_actions[TGSI_OPCODE_LRP].emit = build_tgsi_intrinsic_nomem; bld_base->op_actions[TGSI_OPCODE_LRP].intr_name = "llvm.AMDGPU.lrp"; bld_base->op_actions[TGSI_OPCODE_MOD].emit = emit_mod; + bld_base->op_actions[TGSI_OPCODE_UMSB].emit = emit_umsb; bld_base->op_actions[TGSI_OPCODE_NOT].emit = emit_not; bld_base->op_actions[TGSI_OPCODE_OR].emit = emit_or; bld_base->op_actions[TGSI_OPCODE_POW].emit = build_tgsi_intrinsic_nomem; _______________________________________________ mesa-commit mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/mesa-commit
