fallback: select: G_JUMP_TABLE p0

Run:explore-bc8218b282-20261015-075519
Kind:fallback
Category:select: G_JUMP_TABLE p0
Occurrences:14 in 3 configs, 2 test files
Snippet from:jumptable-section.ll @jt via llvm-extract
Config:-mtriple=riscv64 -code-model=large
Local check:reproduces at bc8218b282
Compiler Explorer:not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define void @jt(i32 signext %in, ptr %out) #0 {
entry:
  switch i32 %in, label %exit [
    i32 1, label %bb1
    i32 2, label %bb2
    i32 3, label %bb3
    i32 4, label %bb4
    i32 5, label %bb5
    i32 6, label %bb6
  ]

bb1:                                              ; preds = %entry
  store i32 4, ptr %out, align 4
  br label %exit

bb2:                                              ; preds = %entry
  store i32 3, ptr %out, align 4
  br label %exit

bb3:                                              ; preds = %entry
  store i32 2, ptr %out, align 4
  br label %exit

bb4:                                              ; preds = %entry
  store i32 1, ptr %out, align 4
  br label %exit

bb5:                                              ; preds = %entry
  store i32 100, ptr %out, align 4
  br label %exit

bb6:                                              ; preds = %entry
  store i32 200, ptr %out, align 4
  br label %exit

exit:                                             ; preds = %bb6, %bb5, %bb4, %bb3, %bb2, %bb1, %entry
  ret void
}

attributes #0 = { nounwind }

Reproduce:

llc -mtriple=riscv64 -code-model=large -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv64 -code-model=large -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: cannot select: %10:gprb(p0) = G_JUMP_TABLE %jump-table.0 (in function: jt)
warning: Instruction selection used fallback path for jt

Occurrences (14):

InputFunctionConfig
jumptable-section.lljt-mtriple=riscv64 -code-model=large
jumptable-section.lljt-mtriple=riscv64 -code-model=large -function-sections
jumptable.llabove_threshold-mtriple=riscv64 -code-model=large -verify-machineinstrs
jumptable-section.11d6c2797c.ll (mutant of jumptable-section.ll)jt-mtriple=riscv64 -code-model=large
jumptable-section.27c682ba1a.ll (mutant of jumptable-section.ll)jt-mtriple=riscv64 -code-model=large
jumptable-section.4fefa152ef.ll (mutant of jumptable-section.ll)jt-mtriple=riscv64 -code-model=large
jumptable-section.7149b69a6d.ll (mutant of jumptable-section.ll)jt-mtriple=riscv64 -code-model=large -function-sections
jumptable-section.d7d805247a.ll (mutant of jumptable-section.ll)jt-mtriple=riscv64 -code-model=large -function-sections
jumptable-section.dd38772482.ll (mutant of jumptable-section.ll)jt-mtriple=riscv64 -code-model=large -function-sections
jumptable.15f5bc355e.ll (mutant of jumptable.ll)above_threshold-mtriple=riscv64 -code-model=large -verify-machineinstrs
jumptable.1ced8ffc68.ll (mutant of jumptable.ll)above_threshold-mtriple=riscv64 -code-model=large -verify-machineinstrs
jumptable.80667fffdb.ll (mutant of jumptable.ll)above_threshold-mtriple=riscv64 -code-model=large -verify-machineinstrs
jumptable.94c118186e.ll (mutant of jumptable.ll)above_threshold-mtriple=riscv64 -code-model=large -verify-machineinstrs
jumptable.dcfd1e2705.ll (mutant of jumptable.ll)above_threshold-mtriple=riscv64 -code-model=large -verify-machineinstrs

Generated 2026-10-15 08:05 UTC.