fallback: legalize: G_CTLZ_ZERO_POISON s32,s96
| Run: | explore-04ca53e65f-20261014-114124 |
| Kind: | fallback |
| Category: | legalize: G_CTLZ_ZERO_POISON s32,s96 NEW |
| Occurrences: | 5 in 5 configs, 1 test files |
| Snippet from: | clmul.30257e3823.ll (mutant of clmul.ll) @clmul_i96 via llvm-extract + llvm-reduce |
| Config: | -mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs |
| Local check: | reproduces at 04ca53e65f |
| Compiler Explorer: | https://godbolt.org/z/fjYos7Gre (llc-assertions-trunk, checked 2026-10-14 11:50 UTC): G reproduces |
Snippet:
define i96 @clmul_i96(i96 %x) {
%B = sdiv i96 %x, 0
ret i96 %B
}
Compiler Explorer panes:
| Pane | Options | Exit | Insts | stderr |
|---|
| GlobalISel | -mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* | 0 | 275 | remark: <unknown>:0:0: unable to legalize instruction: %1050:_(s32) = G_CTLZ_ZERO_POISON %10:_(s96) (in function: clmul_i96)
warning: Instruction selection used fallback path for clmul_i96 |
| SelectionDAG (control) | -mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs -global-isel=0 | 0 | 275 | - |
Reproduce:
llc -mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs -global-isel=0 snippet.ll -o -
Local llc output:
remark: <unknown>:0:0: unable to legalize instruction: %1050:_(s32) = G_CTLZ_ZERO_POISON %10:_(s96) (in function: clmul_i96)
warning: Instruction selection used fallback path for clmul_i96
Occurrences (5):
| Input | Function | Config |
|---|
| clmul.30257e3823.ll (mutant of clmul.ll) | clmul_i96 | -mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs |
| clmul.4c1ab36848.ll (mutant of clmul.ll) | clmul_i96 | -mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs |
| clmul.5247ecf478.ll (mutant of clmul.ll) | clmul_i96 | -mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs |
| clmul.bec811e5ef.ll (mutant of clmul.ll) | clmul_i96 | -mtriple=riscv32 -verify-machineinstrs |
| clmul.fd31fa9b09.ll (mutant of clmul.ll) | clmul_i96 | -mtriple=riscv32 -mattr=+m -verify-machineinstrs |
Generated 2026-10-15 08:05 UTC.