Module: Mesa Branch: main Commit: a6459e0f7bcb662130c79764ccf54ccfa9151182 URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=a6459e0f7bcb662130c79764ccf54ccfa9151182
Author: Sviatoslav Peleshko <[email protected]> Date: Mon Nov 13 13:40:10 2023 +0200 nir/loop_analyze: Don't test non-positive iterations count Testing negative iterations count makes no sense, and can cause issues when the unsigned type is used. Testing 0 iterations is already covered with will_break_on_first_iteration, so it can be skipped too. Fixes: 6772a17a ("nir: Add a loop analysis pass") Closes: https://gitlab.freedesktop.org/mesa/mesa/-/issues/9913 Signed-off-by: Sviatoslav Peleshko <[email protected]> Reviewed-by: Ian Romanick <[email protected]> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/26173> --- src/compiler/nir/nir_loop_analyze.c | 4 +++- src/compiler/nir/tests/loop_analyze_tests.cpp | 11 +++++++++++ 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/src/compiler/nir/nir_loop_analyze.c b/src/compiler/nir/nir_loop_analyze.c index 293f83c6767..a37afa03bef 100644 --- a/src/compiler/nir/nir_loop_analyze.c +++ b/src/compiler/nir/nir_loop_analyze.c @@ -1171,11 +1171,13 @@ calculate_iterations(nir_scalar basis, nir_scalar limit_basis, */ for (int bias = -1; bias <= 1; bias++) { const int iter_bias = iter_int + bias; + if (iter_bias < 1) + continue; if (test_iterations(iter_bias, step, limit, alu_op, bit_size, induction_base_type, initial, limit_rhs, invert_cond, execution_mode)) { - return iter_bias > 0 ? iter_bias - trip_offset : iter_bias; + return iter_bias - trip_offset; } } diff --git a/src/compiler/nir/tests/loop_analyze_tests.cpp b/src/compiler/nir/tests/loop_analyze_tests.cpp index 24415c9b2a7..69b31693872 100644 --- a/src/compiler/nir/tests/loop_analyze_tests.cpp +++ b/src/compiler/nir/tests/loop_analyze_tests.cpp @@ -285,6 +285,7 @@ COMPARE_REVERSE(ishl) INOT_COMPARE(ilt_rev) INOT_COMPARE(ine) +INOT_COMPARE(uge_rev) #define CMP_MIN(cmp, min) \ static nir_def *nir_##cmp##_##min(nir_builder *b, nir_def *counter, nir_def *limit) \ @@ -635,6 +636,16 @@ KNOWN_COUNT_TEST(0x0000000a, 0x00000005, 0xffffffff, inot_ilt_rev, iadd, 5) */ UNKNOWN_COUNT_TEST(0x0000000a, 0x00000005, 0xffffffff, inot_ilt_imin_rev, iadd) +/* uint i = 0; + * while (true) { + * if (!(0 >= i)) + * break; + * + * i += 1; + * } + */ +KNOWN_COUNT_TEST(0x00000000, 0x00000000, 0x00000001, inot_uge_rev, iadd, 1) + /* uint i = 0; * while (true) { * if (i != 0)
