fallback: legalize: G

fallback: legalize: G_SUB <8 x s8>

Run:	main-04ca53e65f-20261014-105623
Kind:	fallback
Category:	legalize: G_SUB <8 x s8>
Occurrences:	35 in 29 configs, 6 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 (35):

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`
atomic-load-store.08b809c64b.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv64 -mattr=+a,+ztso,+no-trailing-seq-cst-fence -verify-machineinstrs`
atomic-load-store.0c36c68140.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv64 -mattr=+a,+no-trailing-seq-cst-fence -verify-machineinstrs`
atomic-load-store.0e1ee5b84b.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-load-store.23f09415ca.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv64 -verify-machineinstrs`
atomic-load-store.2e60620ba2.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv32 -mattr=+a,+ztso,+no-trailing-seq-cst-fence -verify-machineinstrs`
atomic-load-store.31020db55d.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv32 -mattr=+a,+zalasr -verify-machineinstrs`
atomic-load-store.3c10df9574.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv64 -mattr=+a,+zalasr -verify-machineinstrs`
atomic-load-store.4b3a1e958c.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv64 -mattr=+a -verify-machineinstrs`
atomic-load-store.4cfd67ecf0.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv32 -mattr=+a,+zalasr,+ztso -verify-machineinstrs`
atomic-load-store.6e9d154b9b.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-load-store.7ddccdf599.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv32 -mattr=+a,+ztso -verify-machineinstrs`
atomic-load-store.a7f6e02be5.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv64 -mattr=+a,+ztso -verify-machineinstrs`
atomic-load-store.ba8498d254.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv32 -verify-machineinstrs`
atomic-load-store.d8443e9438.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv32 -mattr=+a,+no-trailing-seq-cst-fence -verify-machineinstrs`
atomic-load-store.ea53d53208.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv32 -mattr=+a -verify-machineinstrs`
atomic-load-store.fa73b0d57c.ll (mutant of atomic-load-store.ll)	atomic_load_i64_acquire	`-mtriple=riscv64 -mattr=+a,+zalasr,+ztso -verify-machineinstrs`
div.3b04bb3193.ll (mutant of div.ll)	udiv16_constant_lhs	`-mtriple=riscv64 -verify-machineinstrs`
div.83dafc017c.ll (mutant of div.ll)	udiv16_constant_lhs	`-mtriple=riscv32 -verify-machineinstrs`
div.d5aae63d39.ll (mutant of div.ll)	udiv16_constant_lhs	`-mtriple=riscv32 -mattr=+m -verify-machineinstrs`
div.eaa9a0a65d.ll (mutant of div.ll)	udiv16_constant_lhs	`-mtriple=riscv64 -mattr=+m -verify-machineinstrs`
float-intrinsics.17614da203.ll (mutant of float-intrinsics.ll)	atan2_f32	`-mtriple=riscv64 -mattr=+zfinx -verify-machineinstrs -target-abi=lp64`
float-intrinsics.2003fc42c3.ll (mutant of float-intrinsics.ll)	atan2_f32	`-mtriple=riscv32 -mattr=+d -verify-machineinstrs -target-abi=ilp32f`
float-intrinsics.3365767ad4.ll (mutant of float-intrinsics.ll)	atan2_f32	`-mtriple=riscv32 -mattr=+f -verify-machineinstrs -target-abi=ilp32f`
float-intrinsics.4bf26ff365.ll (mutant of float-intrinsics.ll)	atan2_f32	`-mtriple=riscv64 -verify-machineinstrs`
float-intrinsics.54913e1226.ll (mutant of float-intrinsics.ll)	atan2_f32	`-mtriple=riscv32 -mattr=+zfinx -verify-machineinstrs -target-abi=ilp32`
float-intrinsics.a9c661f418.ll (mutant of float-intrinsics.ll)	atan2_f32	`-mtriple=riscv64 -mattr=+f -verify-machineinstrs -target-abi=lp64f`
float-intrinsics.b98ef217d7.ll (mutant of float-intrinsics.ll)	atan2_f32	`-mtriple=riscv64 -mattr=+d -verify-machineinstrs -target-abi=lp64d`
float-intrinsics.e7ae11b5b5.ll (mutant of float-intrinsics.ll)	atan2_f32	`-mtriple=riscv32 -verify-machineinstrs`
float-zfa.517287effe.ll (mutant of float-zfa.ll)	fmaxm_s	`-mtriple=riscv64 -target-abi lp64f -mattr=+zfa`
float-zfa.736a1a4507.ll (mutant of float-zfa.ll)	fmaxm_s	`-mtriple=riscv32 -target-abi ilp32f -mattr=+zfa`
xtheadmemidx.11677d3231.ll (mutant of xtheadmemidx.ll)	srd	`-mtriple=riscv64 -mattr=+d,+xtheadmemidx -verify-machineinstrs`
xtheadmemidx.63d39a0c57.ll (mutant of xtheadmemidx.ll)	srd	`-mtriple=riscv32 -mattr=+d,+xtheadmemidx -verify-machineinstrs`

Generated 2026-10-15 08:05 UTC.