On 12/19/23 23:55, Juzhe-Zhong wrote:
While trying to fix bugs of PR113097, notice this following situation we
generate redundant vsetvli
_255 = SELECT_VL (3, POLY_INT_CST [4, 4]);
COND_LEN (..., _255)
Before this patch:
vsetivli a5, 3...
...
vadd.vv (use a5)
After this patch:
...
vadd.vv (use AVL = 3)
The reason we can do this is because known_ge (3, [4,4]) is true.
It's safe to apply such optimization
Tested on both RV32 and RV64 full coverage testing, no regression.
PR target/113087
gcc/ChangeLog:
* config/riscv/riscv-v.cc (expand_select_vl): Optimize SELECT_VL.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/rvv/autovec/pr113087-2.c: New test.
OK. THanks!
jeff
