fallback: legalize: G_ATOMICRMW

fallback: legalize: G_ATOMICRMW_SUB s32,p0

Run:	explore-bc8218b282-20261015-075519
Kind:	fallback
Category:	legalize: G_ATOMICRMW_SUB s32,p0
Occurrences:	30 in 6 configs, 4 test files
Snippet from:	forced-atomics.ll @rmw32_sub_seq_cst via llvm-extract
Config:	`-mtriple=riscv32 -mattr=+forced-atomics`
Local check:	reproduces at bc8218b282
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define i32 @rmw32_sub_seq_cst(ptr %p) #0 {
  %v = atomicrmw sub ptr %p, i32 1 seq_cst, align 4
  ret i32 %v
}

attributes #0 = { nounwind }

Reproduce:

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

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %1:_(s32) = G_ATOMICRMW_SUB %0:_(p0), %2:_ :: (load store seq_cst (s32) on %ir.p) (in function: rmw32_sub_seq_cst)
warning: Instruction selection used fallback path for rmw32_sub_seq_cst

Occurrences (30):

Input	Function	Config
atomic-rmw-sub.ll	atomicrmw_sub_i32_constant	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.ll	atomicrmw_sub_i32_neg	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.ll	atomicrmw_sub_i32_constant	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.ll	atomicrmw_sub_i32_neg	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_monotonic	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_acquire	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_release	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_acq_rel	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_seq_cst	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_monotonic	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_acquire	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_release	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_acq_rel	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw.ll	atomicrmw_sub_i32_seq_cst	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-signext.ll	atomicrmw_sub_i32_monotonic	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-signext.ll	atomicrmw_sub_i32_monotonic_crossbb	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-signext.ll	atomicrmw_sub_i32_monotonic	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-signext.ll	atomicrmw_sub_i32_monotonic_crossbb	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
forced-atomics.ll	rmw32_sub_seq_cst	`-mtriple=riscv32 -mattr=+forced-atomics`
forced-atomics.ll	rmw32_sub_seq_cst	`-mtriple=riscv32 -mattr=+forced-atomics,+no-trailing-seq-cst-fence`
forced-atomics.ll	rmw32_sub_seq_cst	`-mtriple=riscv64 -mattr=+forced-atomics`
forced-atomics.ll	rmw32_sub_seq_cst	`-mtriple=riscv64 -mattr=+forced-atomics,+no-trailing-seq-cst-fence`
atomic-rmw-sub.2bd2f0251a.ll (mutant of atomic-rmw-sub.ll)	atomicrmw_sub_i32_neg	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.34ee8f98d1.ll (mutant of atomic-rmw-sub.ll)	atomicrmw_sub_i32_neg	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.7675b581fb.ll (mutant of atomic-rmw-sub.ll)	atomicrmw_sub_i32_neg	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.8ff138eaff.ll (mutant of atomic-rmw-sub.ll)	atomicrmw_sub_i32_constant	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.8ff138eaff.ll (mutant of atomic-rmw-sub.ll)	atomicrmw_sub_i32_neg	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.9567174ac5.ll (mutant of atomic-rmw-sub.ll)	atomicrmw_sub_i32_neg	`-mtriple=riscv32 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.9f6ea6a66e.ll (mutant of atomic-rmw-sub.ll)	atomicrmw_sub_i32_constant	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`
atomic-rmw-sub.9f6ea6a66e.ll (mutant of atomic-rmw-sub.ll)	atomicrmw_sub_i32_neg	`-mtriple=riscv64 -mattr=+zalrsc -verify-machineinstrs`

Generated 2026-10-15 08:05 UTC.