fallback: legalize: G_CLMUL <2 x s64>

Run:	main-bc8218b282-20261015-074651
Kind:	fallback
Category:	legalize: G_CLMUL <2 x s64>
Occurrences:	26 in 10 configs, 1 test files
Snippet from:	clmul.ll @commutative_clmul_v2i64 via llvm-extract
Config:	`-mtriple=riscv32 -mattr=+m -verify-machineinstrs`
Local check:	reproduces at bc8218b282
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define void @commutative_clmul_v2i64(<2 x i64> %x, <2 x i64> %y, ptr %p0, ptr %p1) #0 {
  %xy = call <2 x i64> @llvm.clmul.v2i64(<2 x i64> %x, <2 x i64> %y)
  %yx = call <2 x i64> @llvm.clmul.v2i64(<2 x i64> %y, <2 x i64> %x)
  store <2 x i64> %xy, ptr %p0, align 16
  store <2 x i64> %yx, ptr %p1, align 16
  ret void
}

; Function Attrs: nocallback nocreateundeforpoison nofree nosync nounwind speculatable willreturn memory(none)
declare <2 x i64> @llvm.clmul.v2i64(<2 x i64>, <2 x i64>) #1

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

Reproduce:

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

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %7:_(<2 x s64>) = G_CLMUL %1:_, %0:_ (in function: commutative_clmul_v2i64)
warning: Instruction selection used fallback path for commutative_clmul_v2i64

Occurrences (26):

Input	Function	Config
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m -verify-machineinstrs`
clmul.ll	mul_use_commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m -verify-machineinstrs`
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs`
clmul.ll	mul_use_commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs`
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs`
clmul.ll	mul_use_commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs`
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m,+zvbc -verify-machineinstrs`
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv32 -verify-machineinstrs`
clmul.ll	mul_use_commutative_clmul_v2i64	`-mtriple=riscv32 -verify-machineinstrs`
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m -verify-machineinstrs`
clmul.ll	mul_use_commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m -verify-machineinstrs`
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m,+zbc -verify-machineinstrs`
clmul.ll	mul_use_commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m,+zbc -verify-machineinstrs`
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m,+zbs -verify-machineinstrs`
clmul.ll	mul_use_commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m,+zbs -verify-machineinstrs`
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m,+zvbc -verify-machineinstrs`
clmul.ll	commutative_clmul_v2i64	`-mtriple=riscv64 -verify-machineinstrs`
clmul.ll	mul_use_commutative_clmul_v2i64	`-mtriple=riscv64 -verify-machineinstrs`
clmul.0e8f48804f.ll (mutant of clmul.ll)	mul_use_commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m,+zbs -verify-machineinstrs`
clmul.262f97cf85.ll (mutant of clmul.ll)	mul_use_commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m -verify-machineinstrs`
clmul.3f9a66782d.ll (mutant of clmul.ll)	mul_use_commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m,+zbc -verify-machineinstrs`
clmul.67130abe3c.ll (mutant of clmul.ll)	mul_use_commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m -verify-machineinstrs`
clmul.893ee2850f.ll (mutant of clmul.ll)	mul_use_commutative_clmul_v2i64	`-mtriple=riscv32 -mattr=+m,+zbc -verify-machineinstrs`
clmul.b6bb6f9108.ll (mutant of clmul.ll)	mul_use_commutative_clmul_v2i64	`-mtriple=riscv64 -mattr=+m,+zbs -verify-machineinstrs`
clmul.b7f1c37b80.ll (mutant of clmul.ll)	mul_use_commutative_clmul_v2i64	`-mtriple=riscv64 -verify-machineinstrs`
clmul.bb5eebfa37.ll (mutant of clmul.ll)	mul_use_commutative_clmul_v2i64	`-mtriple=riscv32 -verify-machineinstrs`

Generated 2026-10-15 08:05 UTC.