fallback: legalize: G_SHUFFLE_VECTOR <2 x s64>

Run:explore-04ca53e65f-20261014-114124
Kind:fallback
Category:legalize: G_SHUFFLE_VECTOR <2 x s64> NEW
Occurrences:1 in 1 configs, 1 test files
Snippet from:xcvbi.79d6eea728.ll (mutant of xcvbi.ll) @select_bneimm_1 via llvm-extract
Config:-O0 -mtriple=riscv32 -mattr=+xcvbi -verify-machineinstrs
Local check:reproduces at 04ca53e65f
Compiler Explorer:not uploaded (over --godbolt-limit or disabled)

Snippet:

@G = external global <2 x i64>
@G.1 = external global <2 x i64>

define i32 @select_bneimm_1(i32 %a, i32 %x, i32 %y) {
entry:
  %LGV1 = load <2 x i64>, ptr @G.1, align 16
  %LGV = load <2 x i64>, ptr @G, align 16
  %cmp.not = icmp ne i32 %a, 0
  %S = shufflevector <2 x i64> %LGV, <2 x i64> %LGV1, <2 x i32> poison
  %cond = select i1 %cmp.not, i32 %y, i32 %x
  store <2 x i64> %S, ptr poison, align 16
  ret i32 %cond
}

Reproduce:

llc -O0 -mtriple=riscv32 -mattr=+xcvbi -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -O0 -mtriple=riscv32 -mattr=+xcvbi -verify-machineinstrs -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %9:_(<2 x s64>) = G_SHUFFLE_VECTOR %5:_(<2 x s64>), %3:_, shufflemask(undef, undef) (in function: select_bneimm_1)
warning: Instruction selection used fallback path for select_bneimm_1

Occurrences (1):

InputFunctionConfig
xcvbi.79d6eea728.ll (mutant of xcvbi.ll)select_bneimm_1-O0 -mtriple=riscv32 -mattr=+xcvbi -verify-machineinstrs

Generated 2026-10-15 08:05 UTC.