fallback: legalize: G_UDIV <4 x s32>

Run:main-04ca53e65f-20261014-105623
Kind:fallback
Category:legalize: G_UDIV <4 x s32> NEW
Occurrences:5 in 4 configs, 3 test files
Snippet from:rv64zbb.5345276861.ll (mutant of rv64zbb.ll) @sub_if_uge_i16 via llvm-extract + llvm-reduce
Config:-mtriple=riscv64 -verify-machineinstrs
Local check:reproduces at 04ca53e65f
Compiler Explorer:https://godbolt.org/z/5P7fqPers (llc-assertions-trunk, checked 2026-10-14 11:04 UTC): G reproduces

Snippet:

define <4 x i32> @sub_if_uge_i16() {
  %B = udiv <4 x i32> splat (i32 1), zeroinitializer
  ret <4 x i32> %B
}

Compiler Explorer panes:

PaneOptionsExitInstsstderr
GlobalISel-mtriple=riscv64 -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.*01remark: <unknown>:0:0: unable to legalize instruction: %5:_(<4 x s32>) = G_UDIV %1:_, %3:_ (in function: sub_if_uge_i16)
warning: Instruction selection used fallback path for sub_if_uge_i16
SelectionDAG (control)-mtriple=riscv64 -verify-machineinstrs -global-isel=001-

Reproduce:

llc -mtriple=riscv64 -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv64 -verify-machineinstrs -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %5:_(<4 x s32>) = G_UDIV %1:_, %3:_ (in function: sub_if_uge_i16)
warning: Instruction selection used fallback path for sub_if_uge_i16

Occurrences (5):

InputFunctionConfig
local-stack-slot-allocation.1dd5da1f74.ll (mutant of local-stack-slot-allocation.ll)frame_pointer-mtriple=riscv64 -verify-machineinstrs
local-stack-slot-allocation.8444f036e6.ll (mutant of local-stack-slot-allocation.ll)frame_pointer-mtriple=riscv32 -verify-machineinstrs
pr63365.b42c41a051.ll (mutant of pr63365.ll)f-mtriple=riscv32
rv64zbb.5345276861.ll (mutant of rv64zbb.ll)sub_if_uge_i16-mtriple=riscv64 -verify-machineinstrs
rv64zbb.c104f736be.ll (mutant of rv64zbb.ll)sub_if_uge_i16-mtriple=riscv64 -mattr=+zbb -verify-machineinstrs

Generated 2026-10-15 08:05 UTC.