fallback: legalize: G_BITCAST s8,<8 x s1>

Run:explore-04ca53e65f-20261014-114124
Kind:fallback
Category:legalize: G_BITCAST s8,<8 x s1>
Occurrences:1 in 1 configs, 1 test files
Snippet from:combine-is_fpclass.ll @iszero_constant_v4f32 via llvm-extract
Config:-mtriple=riscv64 -mattr=+v,+f,+d
Local check:reproduces at 04ca53e65f
Compiler Explorer:not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define i8 @iszero_constant_v4f32() #0 {
  %f = tail call <8 x i1> @llvm.is.fpclass.v8f32(<8 x float> <float 1.000000e+00, float 2.000000e+00, float 3.000000e+00, float 4.000000e+00, float -1.000000e+00, float -2.000000e+00, float -3.000000e+00, float -4.000000e+00>, /* (zero) */ i32 96)
  %r = bitcast <8 x i1> %f to i8
  ret i8 %r
}

; Function Attrs: nocallback nocreateundeforpoison nofree nosync nounwind speculatable willreturn memory(none)
declare <8 x i1> @llvm.is.fpclass.v8f32(<8 x float>, i32 immarg) #1

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

Reproduce:

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

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %10:_(s8) = G_BITCAST %0:_(<8 x s1>) (in function: iszero_constant_v4f32)
warning: Instruction selection used fallback path for iszero_constant_v4f32

Occurrences (1):

InputFunctionConfig
combine-is_fpclass.lliszero_constant_v4f32-mtriple=riscv64 -mattr=+v,+f,+d

Generated 2026-10-15 08:05 UTC.