在 2023/12/10 上午1:03, Xi Ruoyao 写道:
Replace the instruction costs in loongarch_rtx_cost_data constructor
based on micro-benchmark results on LA464 and LA664.
This allows optimizations like "x * 17" to alsl, and "x * 68" to alsl
and slli.
gcc/ChangeLog:
PR target/112936
* config/loongarch/loongarch-def.cc
(loongarch_rtx_cost_data::loongarch_rtx_cost_data): Update
instruction costs per micro-benchmark results.
(loongarch_rtx_cost_optimize_size): Set all instruction costs
to (COSTS_N_INSNS (1) + 1).
* config/loongarch/loongarch.cc (loongarch_rtx_costs): Remove
special case for multiplication when optimizing for size.
Adjust division cost when TARGET_64BIT && !TARGET_DIV32.
Account the extra cost when TARGET_CHECK_ZERO_DIV and
optimizing for speed.
gcc/testsuite/ChangeLog
PR target/112936
* gcc.target/loongarch/mul-const-reduction.c: New test.
---
gcc/config/loongarch/loongarch-def.cc | 39 ++++++++++---------
gcc/config/loongarch/loongarch.cc | 22 +++++------
.../loongarch/mul-const-reduction.c | 11 ++++++
3 files changed, 43 insertions(+), 29 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/loongarch/mul-const-reduction.c
Well, I'm curious about how the value of this cost is obtained.
