diff options
| -rw-r--r-- | src/compiler/nir/nir_loop_analyze.c | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/src/compiler/nir/nir_loop_analyze.c b/src/compiler/nir/nir_loop_analyze.c index 0ac04b82799..4689d2230af 100644 --- a/src/compiler/nir/nir_loop_analyze.c +++ b/src/compiler/nir/nir_loop_analyze.c @@ -648,6 +648,43 @@ get_iteration(nir_op cond_op, nir_const_value initial, nir_const_value step, } static bool +will_break_on_first_iteration(nir_const_value step, + nir_alu_type induction_base_type, + unsigned trip_offset, + nir_op cond_op, unsigned bit_size, + nir_const_value initial, + nir_const_value limit, + bool limit_rhs, bool invert_cond) +{ + if (trip_offset == 1) { + nir_op add_op; + switch (induction_base_type) { + case nir_type_float: + add_op = nir_op_fadd; + break; + case nir_type_int: + case nir_type_uint: + add_op = nir_op_iadd; + break; + default: + unreachable("Unhandled induction variable base type!"); + } + + initial = eval_const_binop(add_op, bit_size, initial, step); + } + + nir_const_value *src[2]; + src[limit_rhs ? 0 : 1] = &initial; + src[limit_rhs ? 1 : 0] = &limit; + + /* Evaluate the loop exit condition */ + nir_const_value result; + nir_eval_const_opcode(cond_op, &result, 1, bit_size, src); + + return invert_cond ? !result.b : result.b; +} + +static bool test_iterations(int32_t iter_int, nir_const_value step, nir_const_value limit, nir_op cond_op, unsigned bit_size, nir_alu_type induction_base_type, @@ -741,6 +778,18 @@ calculate_iterations(nir_const_value initial, nir_const_value step, assert(nir_src_bit_size(alu->src[0].src) == nir_src_bit_size(alu->src[1].src)); unsigned bit_size = nir_src_bit_size(alu->src[0].src); + + /* get_iteration works under assumption that iterator will be + * incremented or decremented until it hits the limit, + * however if the loop condition is false on the first iteration + * get_iteration's assumption is broken. Handle such loops first. + */ + if (will_break_on_first_iteration(step, induction_base_type, trip_offset, + alu_op, bit_size, initial, + limit, limit_rhs, invert_cond)) { + return 0; + } + int iter_int = get_iteration(alu_op, initial, step, limit, bit_size); /* If iter_int is negative the loop is ill-formed or is the conditional is |