fallback: legalize: G_FDIV <4 x s32>

Run:	explore-04ca53e65f-20261014-114124
Kind:	fallback
Category:	legalize: G_FDIV <4 x s32> NEW
Occurrences:	28 in 24 configs, 4 test files
Snippet from:	div.02f3c6bb16.ll (mutant of div.ll) @sdiv_pow2_2 via llvm-extract + llvm-reduce
Config:	`-mtriple=riscv32 -verify-machineinstrs`
Local check:	reproduces at 04ca53e65f
Compiler Explorer:	https://godbolt.org/z/dxrhKW5dh (llc-assertions-trunk, checked 2026-10-14 11:49 UTC): G reproduces

Snippet:

define <4 x float> @sdiv_pow2_2() {
  %B = fdiv <4 x float> zeroinitializer, zeroinitializer
  ret <4 x float> %B
}

Compiler Explorer panes:

Pane	Options	Exit	Insts	stderr
GlobalISel	`-mtriple=riscv32 -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.*`	0	6	remark: <unknown>:0:0: unable to legalize instruction: %3:_(<4 x s32>) = G_FDIV %1:_, %1:_ (in function: sdiv_pow2_2) warning: Instruction selection used fallback path for sdiv_pow2_2
SelectionDAG (control)	`-mtriple=riscv32 -verify-machineinstrs -global-isel=0`	0	6	-

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: %3:_(<4 x s32>) = G_FDIV %1:_, %1:_ (in function: sdiv_pow2_2)
warning: Instruction selection used fallback path for sdiv_pow2_2

Occurrences (28):

Input	Function	Config
atomic-load-store.0767c9f1b5.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv64 -mattr=+a,+ztso -verify-machineinstrs`
atomic-load-store.1b1fb0134a.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv32 -verify-machineinstrs`
atomic-load-store.204f2bc90a.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv64 -verify-machineinstrs`
atomic-load-store.364858b1ad.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-load-store.440badf122.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv32 -mattr=+a,+zalasr -verify-machineinstrs`
atomic-load-store.49a7041fd2.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv64 -mattr=+a,+ztso,+no-trailing-seq-cst-fence -verify-machineinstrs`
atomic-load-store.49fcceabea.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv64 -mattr=+a,+zalasr -verify-machineinstrs`
atomic-load-store.7ea245f64f.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv64 -mattr=+a,+no-trailing-seq-cst-fence -verify-machineinstrs`
atomic-load-store.92c37cd507.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-load-store.a0e08c5a8b.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv32 -mattr=+a,+no-trailing-seq-cst-fence -verify-machineinstrs`
atomic-load-store.ae458914cb.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv32 -mattr=+a,+zalasr,+ztso -verify-machineinstrs`
atomic-load-store.afefe2df07.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv64 -mattr=+a -verify-machineinstrs`
atomic-load-store.b2d4f7317f.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv32 -mattr=+a,+ztso -verify-machineinstrs`
atomic-load-store.cfcbb64398.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv64 -mattr=+a,+zalasr,+ztso -verify-machineinstrs`
atomic-load-store.d4975b933e.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv32 -mattr=+a -verify-machineinstrs`
atomic-load-store.f34bb61656.ll (mutant of atomic-load-store.ll)	atomic_store_i8_release	`-mtriple=riscv32 -mattr=+a,+ztso,+no-trailing-seq-cst-fence -verify-machineinstrs`
div.02f3c6bb16.ll (mutant of div.ll)	sdiv_pow2_2	`-mtriple=riscv32 -verify-machineinstrs`
div.2307b72c36.ll (mutant of div.ll)	sdiv_pow2_2	`-mtriple=riscv64 -verify-machineinstrs`
div.da0e200caf.ll (mutant of div.ll)	sdiv_pow2_2	`-mtriple=riscv32 -mattr=+m -verify-machineinstrs`
div.df27594ace.ll (mutant of div.ll)	sdiv_pow2_2	`-mtriple=riscv64 -mattr=+m -verify-machineinstrs`
float-zfa.71389311f5.ll (mutant of float-zfa.ll)	fround_s_4	`-mtriple=riscv32 -target-abi ilp32f -mattr=+zfa`
float-zfa.784124450a.ll (mutant of float-zfa.ll)	fround_s_4	`-mtriple=riscv64 -target-abi lp64f -mattr=+zfa`
llvm.frexp.1db2bb4251.ll (mutant of llvm.frexp.ll)	test_frexp_v4f32_v4i32_only_use_exp	`-mtriple=riscv64 -mattr=+zdinx -verify-machineinstrs -target-abi=lp64`
llvm.frexp.32a3782db6.ll (mutant of llvm.frexp.ll)	test_frexp_v4f32_v4i32_only_use_exp	`-mtriple=riscv64 -verify-machineinstrs`
llvm.frexp.360a6cf6d3.ll (mutant of llvm.frexp.ll)	test_frexp_v4f32_v4i32_only_use_exp	`-mtriple=riscv64 -mattr=+d -verify-machineinstrs -target-abi=lp64d`
llvm.frexp.522145a860.ll (mutant of llvm.frexp.ll)	test_frexp_v4f32_v4i32_only_use_exp	`-mtriple=riscv32 -mattr=+zdinx -verify-machineinstrs -target-abi=ilp32`
llvm.frexp.8ba90e7dac.ll (mutant of llvm.frexp.ll)	test_frexp_v4f32_v4i32_only_use_exp	`-mtriple=riscv32 -verify-machineinstrs`
llvm.frexp.ba0353f78c.ll (mutant of llvm.frexp.ll)	test_frexp_v4f32_v4i32_only_use_exp	`-mtriple=riscv32 -mattr=+d -verify-machineinstrs -target-abi=ilp32d`

Generated 2026-10-15 08:05 UTC.