fallback: legalize: G_LSHR <2 x s96>

Run:main-bc8218b282-20261015-074651
Kind:fallback
Category:legalize: G_LSHR <2 x s96>
Occurrences:4 in 2 configs, 1 test files
Snippet from:umulh.ll @umulh_v2i48 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 i48> @umulh_v2i48(<2 x i48> %x, <2 x i48> %y) #0 {
  %r = call <2 x i48> @llvm.umulh.v2i48(<2 x i48> %x, <2 x i48> %y)
  ret <2 x i48> %r
}

; Function Attrs: nocallback nocreateundeforpoison nofree nosync nounwind speculatable willreturn memory(none)
declare <2 x i48> @llvm.umulh.v2i48(<2 x i48>, <2 x i48>) #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: %27:_(<2 x s96>) = G_LSHR %24:_, %26:_(<2 x s96>) (in function: umulh_v2i48)
warning: Instruction selection used fallback path for umulh_v2i48

Occurrences (4):

InputFunctionConfig
umulh.llumulh_v2i48-mtriple=riscv32 -mattr=+m
umulh.llumulh_v2i48-mtriple=riscv64 -mattr=+m
umulh.c64d06b6a1.ll (mutant of umulh.ll)umulh_v2i48-mtriple=riscv64 -mattr=+m
umulh.ed142fb998.ll (mutant of umulh.ll)umulh_v2i48-mtriple=riscv32 -mattr=+m

Generated 2026-10-15 08:05 UTC.