fallback: legalize: G_BITCAST s32,<4 x s8>

Run:	explore-04ca53e65f-20261014-114124
Kind:	fallback
Category:	legalize: G_BITCAST s32,<4 x s8>
Occurrences:	14 in 2 configs, 3 test files
Snippet from:	rvp-bitcast-const-fold.ll @pnot_v4i8 via llvm-extract
Config:	`-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
Local check:	reproduces at 04ca53e65f
Compiler Explorer:	not uploaded (over --godbolt-limit or disabled)

Snippet:

define i32 @pnot_v4i8(i32 %a) {
  %bc = bitcast i32 %a to <4 x i8>
  %not = xor <4 x i8> %bc, splat (i8 -1)
  %res = bitcast <4 x i8> %not to i32
  ret i32 %res
}

Reproduce:

llc -mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %5:_(s32) = G_BITCAST %4:_(<4 x s8>) (in function: pnot_v4i8)
warning: Instruction selection used fallback path for pnot_v4i8

Occurrences (14):

Input	Function	Config
rvp-bitcast-const-fold.ll	pnot_v4i8	`-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-bitcast-const-fold.ll	pnot_v4i8	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-narrowing-shift-trunc.ll	trunc_lshr_v4i16_to_v4i8	`-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-narrowing-shift-trunc.ll	trunc_lshr_v4i16_to_v4i8	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-zip.ll	test_punzipe_v4i8_coerce	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-zip.ll	test_punzipo_v4i8_coerce	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-bitcast-const-fold.1469b7f6f0.ll (mutant of rvp-bitcast-const-fold.ll)	pnot_v4i8	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-bitcast-const-fold.b4af127a45.ll (mutant of rvp-bitcast-const-fold.ll)	pnot_v4i8	`-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-bitcast-const-fold.c08cc59e69.ll (mutant of rvp-bitcast-const-fold.ll)	pnot_v4i8	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-bitcast-const-fold.da37ae7903.ll (mutant of rvp-bitcast-const-fold.ll)	pnot_v4i8	`-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-narrowing-shift-trunc.25f89385cc.ll (mutant of rvp-narrowing-shift-trunc.ll)	trunc_lshr_v4i16_to_v4i8	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-narrowing-shift-trunc.613b305852.ll (mutant of rvp-narrowing-shift-trunc.ll)	trunc_lshr_v4i16_to_v4i8	`-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-narrowing-shift-trunc.69f694adae.ll (mutant of rvp-narrowing-shift-trunc.ll)	trunc_lshr_v4i16_to_v4i8	`-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`
rvp-narrowing-shift-trunc.78dfc6533b.ll (mutant of rvp-narrowing-shift-trunc.ll)	trunc_lshr_v4i16_to_v4i8	`-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs`

Generated 2026-10-15 08:05 UTC.