On 8/5/2026 1:26 PM, Robin Dapp wrote:
Hi,
In PR126550 I noticed that we expand a constant vector using a "VLA"
stepped-pattern expansion with several ops (vid, shift, add) while we
could just load the constant from the constant pool. On top, this
particular expansion uses a different constant that it stores in the
constant pool anyway, so it's twice as bad. Until we have better
heuristics, this patch forces known-length vector constants to memory.
Regtested on rv64gcv_zvl512b.
Regards
Robin
gcc/ChangeLog:
* config/riscv/riscv-v.cc (expand_const_vector): Force VLS
constants to mem.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/rvv/autovec/pr126550-2.c: Expect
constant-pool vector load.
Per the discussion in the patchwork meeting. This is quite sensible for
any nontrivial constant. OK.
jeff
