fallback: legalize: G

fallback: legalize: G_SMULH s16

Run:	main-04ca53e65f-20261014-113325
Kind:	fallback
Category:	legalize: G_SMULH s16
Occurrences:	15 in 13 configs, 6 test files
Snippet from:	div.ll @sdiv16_constant via llvm-extract
Config:	`-mtriple=riscv64 -verify-machineinstrs`
Local check:	reproduces at 04ca53e65f
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define i16 @sdiv16_constant(i16 %a) #0 {
  %1 = sdiv i16 %a, 5
  ret i16 %1
}

attributes #0 = { nounwind }

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: %9:_(s16) = G_SMULH %0:_, %5:_ (in function: sdiv16_constant)
warning: Instruction selection used fallback path for sdiv16_constant

Occurrences (15):

Input	Function	Config
div.ll	sdiv16_constant	`-mtriple=riscv64 -verify-machineinstrs`
smulh.ll	smulh_i16	`-mtriple=riscv32`
smulh.ll	smulh_i16	`-mtriple=riscv64`
atomic-cmpxchg.13e849f99f.ll (mutant of atomic-cmpxchg.ll)	cmpxchg_i8_seq_cst_acquire	`-mtriple=riscv64 -verify-machineinstrs`
atomic-cmpxchg.14692cebb5.ll (mutant of atomic-cmpxchg.ll)	cmpxchg_i8_seq_cst_acquire	`-mtriple=riscv64 -mattr=+a,+ztso -verify-machineinstrs`
atomic-cmpxchg.2de4e24086.ll (mutant of atomic-cmpxchg.ll)	cmpxchg_i8_seq_cst_acquire	`-mtriple=riscv64 -mattr=+a,+zacas -verify-machineinstrs`
atomic-cmpxchg.669bec03a7.ll (mutant of atomic-cmpxchg.ll)	cmpxchg_i8_seq_cst_acquire	`-mtriple=riscv64 -mattr=+a -verify-machineinstrs`
atomic-cmpxchg.7729577295.ll (mutant of atomic-cmpxchg.ll)	cmpxchg_i8_seq_cst_acquire	`-mtriple=riscv64 -mattr=+a,+zacas,+zabha -verify-machineinstrs`
atomic-cmpxchg.8e3775d116.ll (mutant of atomic-cmpxchg.ll)	cmpxchg_i8_seq_cst_acquire	`-mtriple=riscv64 -mattr=+a,+ztso,+zacas -verify-machineinstrs`
atomic-cmpxchg.d55c7e8dae.ll (mutant of atomic-cmpxchg.ll)	cmpxchg_i8_seq_cst_acquire	`-mtriple=riscv64 -mattr=+a,+ztso,+zacas,+zabha -verify-machineinstrs`
pr94145.9a2e98269c.ll (mutant of pr94145.ll)	PR94145	`-mtriple=riscv64--`
rv64xtheadbb.326a55284d.ll (mutant of rv64xtheadbb.ll)	findFirstSet_i32	`-mtriple=riscv64 -verify-machineinstrs`
rv64xtheadbb.7cc487f8e3.ll (mutant of rv64xtheadbb.ll)	findFirstSet_i32	`-mtriple=riscv64 -mattr=+xtheadbb -verify-machineinstrs`
rv64xtheadbb.e089c28169.ll (mutant of rv64xtheadbb.ll)	findFirstSet_i32	`-mtriple=riscv64 -mattr=+xtheadbb,+b -verify-machineinstrs`
rv64zbkb-intrinsic.2f32f3a3bc.ll (mutant of rv64zbkb-intrinsic.ll)	brev8_i32_knownbits	`-mtriple=riscv64 -mattr=+zbkb -verify-machineinstrs`

Generated 2026-10-15 08:05 UTC.