fallback: legalize: G_LSHR <2 x s128>

Run:explore-bc8218b282-20261015-075519
Kind:fallback
Category:legalize: G_LSHR <2 x s128>
Occurrences:56 in 12 configs, 3 test files
Snippet from:umulh.ll @umulh_v2i64 via llvm-extract
Config:-mtriple=riscv32 -mattr=+m
Local check:reproduces at bc8218b282
Compiler Explorer:not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define <2 x i64> @umulh_v2i64(<2 x i64> %x, <2 x i64> %y) #0 {
  %r = call <2 x i64> @llvm.umulh.v2i64(<2 x i64> %x, <2 x i64> %y)
  ret <2 x i64> %r
}

; Function Attrs: nocallback nocreateundeforpoison nofree nosync nounwind speculatable willreturn memory(none)
declare <2 x i64> @llvm.umulh.v2i64(<2 x i64>, <2 x i64>) #1

attributes #0 = { nounwind }
attributes #1 = { nocallback nocreateundeforpoison nofree nosync nounwind speculatable willreturn memory(none) }

Reproduce:

llc -mtriple=riscv32 -mattr=+m -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv32 -mattr=+m -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %22:_(<2 x s128>) = G_LSHR %19:_, %21:_(<2 x s128>) (in function: umulh_v2i64)
warning: Instruction selection used fallback path for umulh_v2i64

Occurrences (56) (first 50):

InputFunctionConfig
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m -verify-machineinstrs
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv32 -verify-machineinstrs
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m -verify-machineinstrs
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m,+zbc -verify-machineinstrs
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m,+zbs -verify-machineinstrs
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m,+zvbc -verify-machineinstrs
clmulh.llcommutative_clmulh_v2i64-mtriple=riscv64 -verify-machineinstrs
clmulr.llcommutative_clmulr_v2i64-mtriple=riscv32 -mattr=+m -verify-machineinstrs
clmulr.llcommutative_clmulr_v2i64-mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs
clmulr.llcommutative_clmulr_v2i64-mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs
clmulr.llcommutative_clmulr_v2i64-mtriple=riscv32 -verify-machineinstrs
clmulr.llcommutative_clmulr_v2i64-mtriple=riscv64 -mattr=+m -verify-machineinstrs
clmulr.llcommutative_clmulr_v2i64-mtriple=riscv64 -mattr=+m,+zbc -verify-machineinstrs
clmulr.llcommutative_clmulr_v2i64-mtriple=riscv64 -mattr=+m,+zbs -verify-machineinstrs
clmulr.llcommutative_clmulr_v2i64-mtriple=riscv64 -verify-machineinstrs
umulh.llumulh_v2i64-mtriple=riscv32 -mattr=+m
umulh.llumulh_v2i64-mtriple=riscv64 -mattr=+m
clmulh.4a65d6c7b9.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs
clmulh.4c5462aa52.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs
clmulh.4dec912f28.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m -verify-machineinstrs
clmulh.5403ac3b89.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs
clmulh.5d9bcea33d.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m,+zvbc -verify-machineinstrs
clmulh.6842c22221.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs
clmulh.68f9a00b86.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m,+zvbc -verify-machineinstrs
clmulh.6cf00827e9.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -verify-machineinstrs
clmulh.7045b0159c.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m,+zbc -verify-machineinstrs
clmulh.8750e0c737.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m,+zbc -verify-machineinstrs
clmulh.a791808756.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m,+zbs -verify-machineinstrs
clmulh.b09e43c5b9.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -verify-machineinstrs
clmulh.b284cfd651.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -verify-machineinstrs
clmulh.b69a37db3b.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -verify-machineinstrs
clmulh.bfef447f11.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs
clmulh.c0ded71bc5.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m,+zbs -verify-machineinstrs
clmulh.c2c267cff9.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m -verify-machineinstrs
clmulh.d734b1eacd.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs
clmulh.f0331d98fa.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m -verify-machineinstrs
clmulh.f6aa2ef6a7.ll (mutant of clmulh.ll)commutative_clmulh_v2i64-mtriple=riscv64 -mattr=+m -verify-machineinstrs
clmulr.169563f37e.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs
clmulr.29076a1d4b.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv32 -verify-machineinstrs
clmulr.29c105785f.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv64 -mattr=+m -verify-machineinstrs
clmulr.2e0e97f2f2.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv64 -mattr=+m -verify-machineinstrs
clmulr.30945e70d7.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv64 -verify-machineinstrs
clmulr.6e24d4ed2f.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs
clmulr.8a9cc48869.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv64 -mattr=+m,+zbs -verify-machineinstrs
clmulr.a91d8f084c.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs
clmulr.b94b531521.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs
clmulr.bcb1b58c70.ll (mutant of clmulr.ll)commutative_clmulr_v2i64-mtriple=riscv64 -mattr=+m,+zbc -verify-machineinstrs

Generated 2026-10-15 08:05 UTC.