fallback: legalize: G_ATOMIC_CMPXCHG s64,p0

Run:explore-04ca53e65f-20261014-114124
Kind:fallback
Category:legalize: G_ATOMIC_CMPXCHG s64,p0
Occurrences:14 in 2 configs, 1 test files
Snippet from:forced-atomics.ll @rmw64_fadd_seq_cst via llvm-extract
Config:-mtriple=riscv64 -mattr=+forced-atomics
Local check:reproduces at 04ca53e65f
Compiler Explorer:not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define double @rmw64_fadd_seq_cst(ptr %p) #0 {
  %v = atomicrmw fadd ptr %p, double 1.000000e+00 seq_cst, align 8
  ret double %v
}

attributes #0 = { nounwind }

Reproduce:

llc -mtriple=riscv64 -mattr=+forced-atomics -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv64 -mattr=+forced-atomics -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %14:_(s64) = G_ATOMIC_CMPXCHG %0:_(p0), %2:_, %4:_ :: (load store seq_cst seq_cst (s64) on %ir.p) (in function: rmw64_fadd_seq_cst)
warning: Instruction selection used fallback path for rmw64_fadd_seq_cst

Occurrences (14):

InputFunctionConfig
forced-atomics.llrmw64_fadd_seq_cst-mtriple=riscv64 -mattr=+forced-atomics
forced-atomics.llrmw64_fsub_seq_cst-mtriple=riscv64 -mattr=+forced-atomics
forced-atomics.llrmw64_fmin_seq_cst-mtriple=riscv64 -mattr=+forced-atomics
forced-atomics.llrmw64_fmax_seq_cst-mtriple=riscv64 -mattr=+forced-atomics
forced-atomics.llcmpxchg64_monotonic-mtriple=riscv64 -mattr=+forced-atomics
forced-atomics.llcmpxchg64_seq_cst-mtriple=riscv64 -mattr=+forced-atomics
forced-atomics.llrmw64_fadd_seq_cst-mtriple=riscv64 -mattr=+forced-atomics,+no-trailing-seq-cst-fence
forced-atomics.llrmw64_fsub_seq_cst-mtriple=riscv64 -mattr=+forced-atomics,+no-trailing-seq-cst-fence
forced-atomics.llrmw64_fmin_seq_cst-mtriple=riscv64 -mattr=+forced-atomics,+no-trailing-seq-cst-fence
forced-atomics.llrmw64_fmax_seq_cst-mtriple=riscv64 -mattr=+forced-atomics,+no-trailing-seq-cst-fence
forced-atomics.llcmpxchg64_monotonic-mtriple=riscv64 -mattr=+forced-atomics,+no-trailing-seq-cst-fence
forced-atomics.llcmpxchg64_seq_cst-mtriple=riscv64 -mattr=+forced-atomics,+no-trailing-seq-cst-fence
forced-atomics.a6f78c7989.ll (mutant of forced-atomics.ll)cmpxchg64_seq_cst-mtriple=riscv64 -mattr=+forced-atomics,+no-trailing-seq-cst-fence
forced-atomics.e0adf22bc8.ll (mutant of forced-atomics.ll)cmpxchg64_seq_cst-mtriple=riscv64 -mattr=+forced-atomics

Generated 2026-10-15 08:05 UTC.