On 4/9/25 2:53 PM, Vineet Gupta wrote:
Changes since v2
- Elide abnormal edges before LCM not after LCM
---
vsetvl phase4 uses LCM guided info to insert VSETVL insns, including a
straggler loop for "mising vsetvls" on certain edges. Currently it
asserts on encountering EDGE_ABNORMAL.
When enabling go frontend with V enabled, libgo build hits the assert.
The solution is to filter out abnormal edges from getting into LCM at
all. Existing invalid_opt_bb_p () has such checks for BB predecessors
but not for successors which is what the patch adds.
Crucially, the ICE/fix also depends on avoiding vsetvl hoisting past
non-transparent blocks: That is taken care of by Robin's patch
"RISC-V: Do not lift up vsetvl into non-transparent blocks [PR119547]"
or a different yet related issue.
Reported-by: Heinrich Schuchardt <heinrich.schucha...@canonical.com>
Signed-off-by: Vineet Gupta <vine...@rivosinc.com>
PR target/119533
gcc/ChangeLog:
* config/riscv/riscv-vsetvl.cc (invalid_opt_bb_p): Check for
EDGE_ABNOMAL.
(pre_vsetvl::compute_lcm_local_properties): Dump skipped edge.
gcc/testsuite/ChangeLog:
* go.dg/pr119533-riscv.go: New test.
* go.dg/pr119533-riscv-2.go: New test.
FTR: This was acked in the patch review meeting this morning.
Thanks,
jeff
