fallback: legalize: G_LSHR <8 x s16>
| Run: | main-04ca53e65f-20261014-113325 |
| Kind: | fallback |
| Category: | legalize: G_LSHR <8 x s16> |
| Occurrences: | 9 in 3 configs, 2 test files |
| Snippet from: | rvp-simd-64.ll @test_pasubu_b via llvm-extract |
| Config: | -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs |
| Local check: | reproduces at 04ca53e65f |
| Compiler Explorer: | not uploaded (over --godbolt-limit or disabled) |
Snippet:
define <8 x i8> @test_pasubu_b(<8 x i8> %a, <8 x i8> %b) {
%a_ext = zext <8 x i8> %a to <8 x i16>
%b_ext = zext <8 x i8> %b to <8 x i16>
%sub = sub <8 x i16> %a_ext, %b_ext
%res = lshr <8 x i16> %sub, splat (i16 1)
%res_trunc = trunc <8 x i16> %res to <8 x i8>
ret <8 x i8> %res_trunc
}
Reproduce:
llc -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs -global-isel=0 snippet.ll -o -
Local llc output:
remark: <unknown>:0:0: unable to legalize instruction: %7:_(<8 x s16>) = G_LSHR %4:_, %5:_(<8 x s16>) (in function: test_pasubu_b)
warning: Instruction selection used fallback path for test_pasubu_b
Occurrences (9):
| Input | Function | Config |
|---|
| rvp-simd-64.ll | test_pasubu_b | -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs |
| rvp-simd-64.ll | test_pmulh_b | -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs |
| rvp-simd-64.ll | test_pmulhu_b | -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs |
| rvp-simd-64.ll | test_pmulhsu_b | -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs |
| rvp-simd-64.ll | test_pmulhsu_b_commuted | -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs |
| umulh.ll | umulh_v8i8 | -mtriple=riscv32 -mattr=+m |
| umulh.ll | umulh_v8i8 | -mtriple=riscv64 -mattr=+m |
| umulh.48817cdde7.ll (mutant of umulh.ll) | umulh_v8i8 | -mtriple=riscv32 -mattr=+m |
| umulh.bd6efb007a.ll (mutant of umulh.ll) | umulh_v8i8 | -mtriple=riscv64 -mattr=+m |
Generated 2026-10-15 08:05 UTC.