fallback: legalize: G

fallback: legalize: G_SUB <8 x s8>

Run:	explore-04ca53e65f-20261014-114124
Kind:	fallback
Category:	legalize: G_SUB <8 x s8>
Occurrences:	14 in 11 configs, 5 test files
Snippet from:	rvp-simd-64.ll @test_psub_b via llvm-extract
Config:	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
Local check:	reproduces at 04ca53e65f
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

define <8 x i8> @test_psub_b(<8 x i8> %a, <8 x i8> %b) {
  %res = sub <8 x i8> %a, %b
  ret <8 x i8> %res
}

Reproduce:

llc -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %2:_(<8 x s8>) = G_SUB %0:_, %1:_ (in function: test_psub_b)
warning: Instruction selection used fallback path for test_psub_b

Occurrences (14):

Input	Function	Config
rvp-simd-64.ll	test_psub_b	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-simd-64.ll	test_pdif_b	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-simd-64.ll	test_pdifu_b	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
float-intrinsics.0b77fec9c0.ll (mutant of float-intrinsics.ll)	maximumnum_float	`-mtriple=riscv64 -verify-machineinstrs`
float-intrinsics.12596181bf.ll (mutant of float-intrinsics.ll)	maximumnum_float	`-mtriple=riscv32 -verify-machineinstrs`
float-intrinsics.835bf411f9.ll (mutant of float-intrinsics.ll)	maximumnum_float	`-mtriple=riscv64 -mattr=+f -verify-machineinstrs -target-abi=lp64f`
float-intrinsics.b2896ebb4b.ll (mutant of float-intrinsics.ll)	maximumnum_float	`-mtriple=riscv64 -mattr=+d -verify-machineinstrs -target-abi=lp64d`
float-intrinsics.e9df7ff1a6.ll (mutant of float-intrinsics.ll)	maximumnum_float	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
float-intrinsics.ec985d6fdb.ll (mutant of float-intrinsics.ll)	maximumnum_float	`-mtriple=riscv32 -mattr=+d -verify-machineinstrs -target-abi=ilp32f`
rv32xtheadba.50f6854dd8.ll (mutant of rv32xtheadba.ll)	srli_2_sh1add	`-mtriple=riscv32 -mattr=+m,+xtheadba -verify-machineinstrs`
rv32xtheadba.5e7048f8b1.ll (mutant of rv32xtheadba.ll)	srli_2_sh1add	`-mtriple=riscv32 -mattr=+m -verify-machineinstrs`
rvp-zip.0ff58c9055.ll (mutant of rvp-zip.ll)	test_unzip8hp_v8i8	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
xtheadmemidx.55e8cceec1.ll (mutant of xtheadmemidx.ll)	lurd	`-mtriple=riscv32 -mattr=+d,+xtheadmemidx -verify-machineinstrs`
xtheadmemidx.7f1705b954.ll (mutant of xtheadmemidx.ll)	lurd	`-mtriple=riscv64 -mattr=+d,+xtheadmemidx -verify-machineinstrs`

Generated 2026-10-15 08:05 UTC.