fallback: unable to lower arguments

Run:	main-04ca53e65f-20261014-105623
Kind:	fallback
Category:	unable to lower arguments
Occurrences:	1087 in 24 configs, 20 test files
Snippet from:	bfloat-convert-half.ll @test_h_bf16 via llvm-extract
Config:	`-mtriple=riscv32 -mattr=+zfhmin,+zfbfmin -verify-machineinstrs`
Local check:	reproduces at 04ca53e65f
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define half @test_h_bf16(bfloat %a) #0 {
  %r = bitcast bfloat %a to half
  ret half %r
}

attributes #0 = { nounwind }

Reproduce:

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

Local llc output:

remark: <unknown>:0:0: unable to lower arguments: half (bfloat) (in function: test_h_bf16)
warning: Instruction selection used fallback path for test_h_bf16

Occurrences (1087) (first 50):

Input	Function	Config
bfloat-arith.ll	fadd_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fsub_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fmul_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fdiv_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fsqrt_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fsgnj_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fneg_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fsgnjn_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fabs_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fmin_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fmax_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fmadd_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fmsub_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fnmadd_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fnmadd_s_2	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fnmadd_s_3	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fnmadd_nsz	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fnmsub_bf16	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fnmsub_bf16_2	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fmadd_bf16_contract	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fmsub_bf16_contract	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fnmadd_bf16_contract	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fnmsub_bf16_contract	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-arith.ll	fadd_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fsub_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fmul_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fdiv_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fsqrt_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fsgnj_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fneg_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fsgnjn_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fabs_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fmin_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fmax_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fmadd_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fmsub_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fnmadd_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fnmadd_s_2	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fnmadd_s_3	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fnmadd_nsz	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fnmsub_bf16	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fnmsub_bf16_2	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fmadd_bf16_contract	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fmsub_bf16_contract	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fnmadd_bf16_contract	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-arith.ll	fnmsub_bf16_contract	`-mtriple=riscv64 -mattr=+zfbfmin -verify-machineinstrs -target-abi lp64f`
bfloat-br-fcmp.ll	br_fcmp_false	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-br-fcmp.ll	br_fcmp_oeq	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-br-fcmp.ll	br_fcmp_oeq_alt	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`
bfloat-br-fcmp.ll	br_fcmp_ogt	`-mtriple=riscv32 -mattr=+zfbfmin -verify-machineinstrs -target-abi ilp32f`

Generated 2026-10-15 08:05 UTC.