fallback: legalize: G

fallback: legalize: G_FATAN s16

Run:	explore-04ca53e65f-20261014-114124
Kind:	fallback
Category:	legalize: G_FATAN s16
Occurrences:	28 in 18 configs, 1 test files
Snippet from:	half-intrinsics.ll @atan_f16 via llvm-extract
Config:	`-mtriple=riscv32 -mattr=+d -mattr=+zfh -verify-machineinstrs -target-abi ilp32d`
Local check:	reproduces at 04ca53e65f
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define half @atan_f16(half %a) #0 {
  %1 = call half @llvm.atan.f16(half %a)
  ret half %1
}

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare half @llvm.atan.f16(half) #1

attributes #0 = { nounwind }
attributes #1 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }

Reproduce:

llc -mtriple=riscv32 -mattr=+d -mattr=+zfh -verify-machineinstrs -target-abi ilp32d -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv32 -mattr=+d -mattr=+zfh -verify-machineinstrs -target-abi ilp32d -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %1:_(s16) = G_FATAN %0:_ (in function: atan_f16)
warning: Instruction selection used fallback path for atan_f16

Occurrences (28):

Input	Function	Config
half-intrinsics.ll	atan_f16	`-mtriple=riscv32 -mattr=+d -mattr=+zfh -verify-machineinstrs -target-abi ilp32d`
half-intrinsics.ll	atan_f16	`-mtriple=riscv32 -mattr=+d -mattr=+zfhmin -verify-machineinstrs -target-abi ilp32d`
half-intrinsics.ll	atan_f16	`-mtriple=riscv32 -mattr=+zfh -verify-machineinstrs -target-abi ilp32f`
half-intrinsics.ll	atan_f16	`-mtriple=riscv32 -mattr=+zfhmin -verify-machineinstrs -target-abi ilp32f`
half-intrinsics.ll	atan_f16	`-mtriple=riscv32 -verify-machineinstrs`
half-intrinsics.ll	atan_f16	`-mtriple=riscv64 -mattr=+d -mattr=+zfh -verify-machineinstrs -target-abi lp64d`
half-intrinsics.ll	atan_f16	`-mtriple=riscv64 -mattr=+d -mattr=+zfhmin -verify-machineinstrs -target-abi lp64d`
half-intrinsics.ll	atan_f16	`-mtriple=riscv64 -mattr=+zfh -verify-machineinstrs -target-abi lp64f`
half-intrinsics.ll	atan_f16	`-mtriple=riscv64 -mattr=+zfhmin -verify-machineinstrs -target-abi lp64f`
half-intrinsics.ll	atan_f16	`-mtriple=riscv64 -verify-machineinstrs`
half-intrinsics.3144008503.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv32 -mattr=+zdinx -mattr=+zhinxmin -verify-machineinstrs -target-abi ilp32`
half-intrinsics.49ba4d2aae.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv32 -mattr=+d -mattr=+zfhmin -verify-machineinstrs -target-abi ilp32d`
half-intrinsics.54e6967a29.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv64 -verify-machineinstrs`
half-intrinsics.668a041ddf.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv32 -verify-machineinstrs`
half-intrinsics.7045dfe7cf.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv64 -mattr=+zdinx -mattr=+zhinxmin -verify-machineinstrs -target-abi lp64`
half-intrinsics.7486cd3138.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv32 -mattr=+zdinx -mattr=+zhinx -verify-machineinstrs -target-abi ilp32`
half-intrinsics.762c088875.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv64 -mattr=+zhinx -verify-machineinstrs -target-abi lp64`
half-intrinsics.7bc1619cf4.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv64 -mattr=+zhinxmin -verify-machineinstrs -target-abi lp64`
half-intrinsics.8fa312e73a.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv64 -mattr=+zfhmin -verify-machineinstrs -target-abi lp64f`
half-intrinsics.99d52cb358.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv32 -mattr=+zhinx -verify-machineinstrs -target-abi ilp32`
half-intrinsics.a7c012864d.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv32 -mattr=+zhinxmin -verify-machineinstrs -target-abi ilp32`
half-intrinsics.c416a33bff.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv64 -mattr=+zfh -verify-machineinstrs -target-abi lp64f`
half-intrinsics.cc2be43f7a.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv32 -mattr=+d -mattr=+zfh -verify-machineinstrs -target-abi ilp32d`
half-intrinsics.cfe8f74050.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv64 -mattr=+zdinx -mattr=+zhinx -verify-machineinstrs -target-abi lp64`
half-intrinsics.e5ef805b87.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv32 -mattr=+zfh -verify-machineinstrs -target-abi ilp32f`
half-intrinsics.ebf7220338.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv64 -mattr=+d -mattr=+zfh -verify-machineinstrs -target-abi lp64d`
half-intrinsics.f3dc52ee94.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv64 -mattr=+d -mattr=+zfhmin -verify-machineinstrs -target-abi lp64d`
half-intrinsics.f758b8ed33.ll (mutant of half-intrinsics.ll)	atan_f16	`-mtriple=riscv32 -mattr=+zfhmin -verify-machineinstrs -target-abi ilp32f`

Generated 2026-10-15 08:05 UTC.