fallback: legalize: G

fallback: legalize: G_UMULH s64

Run:	main-04ca53e65f-20261014-113325
Kind:	fallback
Category:	legalize: G_UMULH s64
Occurrences:	34 in 10 configs, 11 test files
Snippet from:	div.ll @udiv64_constant via llvm-extract
Config:	`-mtriple=riscv32 -verify-machineinstrs`
Local check:	reproduces at 04ca53e65f
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define i64 @udiv64_constant(i64 %a) #0 {
  %1 = udiv i64 %a, 5
  ret i64 %1
}

attributes #0 = { nounwind }

Reproduce:

llc -mtriple=riscv32 -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv32 -verify-machineinstrs -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %11:_(s64) = G_UMULH %0:_, %8:_ (in function: udiv64_constant)
warning: Instruction selection used fallback path for udiv64_constant

Occurrences (34):

Input	Function	Config
bitint-fp-conv-200.ll	test_float_to_bitint_200	`-mtriple=riscv32 -verify-machineinstrs`
div.ll	udiv64_constant	`-mtriple=riscv32 -verify-machineinstrs`
fp128.ll	fptosi_fp128_to_i96	`-mtriple=riscv32 -verify-machineinstrs`
fpclamptosat.ll	stest_f64i64	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
fpclamptosat.ll	ustest_f64i64	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
fpclamptosat.ll	stest_f32i64	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
fpclamptosat.ll	ustest_f32i64	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
fpclamptosat.ll	stest_f64i64_mm	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
fpclamptosat.ll	ustest_f64i64_mm	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
fpclamptosat.ll	stest_f32i64_mm	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
fpclamptosat.ll	ustest_f32i64_mm	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
mul.ll	muli128_m3840	`-mtriple=riscv32 -verify-machineinstrs`
mul.ll	muli128_m63	`-mtriple=riscv32 -verify-machineinstrs`
mul.ll	mulhsu_i64	`-mtriple=riscv32 -verify-machineinstrs`
umulh.ll	umulh_i64	`-mtriple=riscv32`
umulh.ll	umulh_v1i64	`-mtriple=riscv32`
urem-lkk.ll	dont_fold_urem_i64	`-mtriple=riscv32 -verify-machineinstrs`
bitint-fp-conv-200.99c7233fcd.ll (mutant of bitint-fp-conv-200.ll)	test_float_to_bitint_200	`-mtriple=riscv32 -verify-machineinstrs`
bitint-fp-conv-200.ad4377eb8f.ll (mutant of bitint-fp-conv-200.ll)	test_float_to_bitint_200	`-mtriple=riscv32 -verify-machineinstrs`
bitint-fp-conv-200.ef9db54422.ll (mutant of bitint-fp-conv-200.ll)	test_float_to_bitint_200	`-mtriple=riscv32 -verify-machineinstrs`
condops.439c8f23b3.ll (mutant of condops.ll)	zero2_seteq	`-mtriple=riscv32 -target-abi=ilp32f -mattr=+f,+zbs,+zicond`
condops.a21005d443.ll (mutant of condops.ll)	zero2_seteq	`-mtriple=riscv32 -target-abi=ilp32f -mattr=+f,+zbs`
div.e19394eece.ll (mutant of div.ll)	udiv64_constant	`-mtriple=riscv32 -verify-machineinstrs`
float-imm.67fd8238b5.ll (mutant of float-imm.ll)	poison	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
fp128.b26b124633.ll (mutant of fp128.ll)	fptosi_fp128_to_i96	`-mtriple=riscv32 -verify-machineinstrs`
fp128.f4e1a8cc32.ll (mutant of fp128.ll)	fptosi_fp128_to_i96	`-mtriple=riscv32 -verify-machineinstrs`
fpenv.cb65fb5ca0.ll (mutant of fpenv.ll)	func_04	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs`
half-imm.0ce767f9cd.ll (mutant of half-imm.ll)	poison	`-mtriple=riscv32 -mattr=+zfhmin -verify-machineinstrs -target-abi ilp32f`
half-imm.4350d81703.ll (mutant of half-imm.ll)	poison	`-mtriple=riscv32 -mattr=+zhinxmin -verify-machineinstrs -target-abi ilp32`
half-imm.60926d88b8.ll (mutant of half-imm.ll)	poison	`-mtriple=riscv32 -mattr=+zfh -verify-machineinstrs -target-abi ilp32f`
half-imm.75fe6d8a7d.ll (mutant of half-imm.ll)	poison	`-mtriple=riscv32 -mattr=+zhinx -verify-machineinstrs -target-abi ilp32`
umulh.5a4874298d.ll (mutant of umulh.ll)	umulh_i64	`-mtriple=riscv32`
umulh.7504ed3113.ll (mutant of umulh.ll)	umulh_i64	`-mtriple=riscv32`
urem-lkk.5bc17297b1.ll (mutant of urem-lkk.ll)	dont_fold_urem_i64	`-mtriple=riscv32 -verify-machineinstrs`

Generated 2026-10-15 08:05 UTC.