On Wed, 2023-12-13 at 20:22 +0800, chenglulu wrote: 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. I just make a loop containing 1000 mul.w instructions, then run the loop 1000000 times and compare the time usage with running another loop containing 1000 addi.w instructions iterated 1000000 times too. > Likewise for other instructions... -- Xi Ruoyao <xry...@xry111.site> School of Aerospace Science and Technology, Xidian University
