fallback: legalize: G_INTRINSIC <4 x s16>,<4 x s8>,s32

Snippet:

; Function Attrs: nocallback nofree nosync nounwind speculatable willreturn memory(none)
declare <4 x i16> @llvm.riscv.pwsll.v4i16.v4i8(<4 x i8>, i32) #0

define <4 x i16> @pwsll_v4i8(<4 x i8> %x, i16 %shamt) {
  %shamt.ext = zext i16 %shamt to i32
  %res = call <4 x i16> @llvm.riscv.pwsll.v4i16.v4i8(<4 x i8> %x, i32 %shamt.ext)
  ret <4 x i16> %res
}

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

Reproduce:

llc -mtriple=riscv64 -mattr=+experimental-p -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv64 -mattr=+experimental-p -verify-machineinstrs -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %6:_(<4 x s16>) = G_INTRINSIC intrinsic(@llvm.riscv.pwsll), %0:_(<4 x s8>), %5:_(s32) (in function: pwsll_v4i8)
warning: Instruction selection used fallback path for pwsll_v4i8

Occurrences (10):

Generated 2026-10-15 08:05 UTC.