fallback: legalize: G_SELECT <2 x s16>,<2 x s1>

Run:main-04ca53e65f-20261014-113325
Kind:fallback
Category:legalize: G_SELECT <2 x s16>,<2 x s1>
Occurrences:1 in 1 configs, 1 test files
Snippet from:rvp-simd-32.ll @test_pssla_hs 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 <2 x i16> @test_pssla_hs(<2 x i16> %a, i16 %shamt) {
  %insert = insertelement <2 x i16> poison, i16 %shamt, i32 0
  %b = shufflevector <2 x i16> %insert, <2 x i16> poison, <2 x i32> zeroinitializer
  %res = call <2 x i16> @llvm.sshl.sat.v2i16(<2 x i16> %a, <2 x i16> %b)
  ret <2 x i16> %res
}

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare <2 x i16> @llvm.sshl.sat.v2i16(<2 x i16>, <2 x i16>) #0

attributes #0 = { nocallback nofree nosync nounwind speculatable willreturn memory(none) }

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: %9:_(<2 x s16>) = G_SELECT %24:_(<2 x s1>), %23:_, %14:_ (in function: test_pssla_hs)
warning: Instruction selection used fallback path for test_pssla_hs

Occurrences (1):

InputFunctionConfig
rvp-simd-32.lltest_pssla_hs-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs

Generated 2026-10-15 08:05 UTC.