fallback: select: G_INTRINSIC s32,<vscale x 1 x s32>

Snippet:

declare signext i32 @bar(i32 signext)

; Function Attrs: nounwind
define void @test20(<vscale x 1 x i32> %arg, i32 signext %arg1) #0 {
bb:
  %i = call i32 @llvm.riscv.vmv.x.s.nxv1i32(<vscale x 1 x i32> %arg)
  br label %bb2

bb2:                                              ; preds = %bb2, %bb
  %i3 = phi i32 [ %i, %bb ], [ %i5, %bb2 ]
  %i4 = tail call signext i32 @bar(i32 signext %i3)
  %i5 = shl i32 %i3, %arg1
  %i6 = icmp eq i32 %i4, 0
  br i1 %i6, label %bb7, label %bb2

bb7:                                              ; preds = %bb2
  ret void
}

; Function Attrs: nocallback nofree nosync nounwind willreturn memory(none)
declare i32 @llvm.riscv.vmv.x.s.nxv1i32(<vscale x 1 x i32>) #1

attributes #0 = { nounwind }
attributes #1 = { nocallback nofree nosync nounwind willreturn memory(none) }

Reproduce:

llc -mtriple=riscv64 -mattr=+m,+f,+zknh,+v -target-abi=lp64f -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv64 -mattr=+m,+f,+zknh,+v -target-abi=lp64f -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: cannot select: %4:gprb(s32) = G_INTRINSIC intrinsic(@llvm.riscv.vmv.x.s), %0:vrb(<vscale x 1 x s32>) (in function: test20)
warning: Instruction selection used fallback path for test20

Occurrences (3):

Generated 2026-10-15 08:05 UTC.