fallback: legalize: G_BITCAST s64,<8 x s8>

Run:explore-bc8218b282-20261015-075519
Kind:fallback
Category:legalize: G_BITCAST s64,<8 x s8>
Occurrences:14 in 3 configs, 3 test files
Snippet from:rvp-bitcast-const-fold.ll @pnot_v8i8 via llvm-extract
Config:-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
Local check:reproduces at bc8218b282
Compiler Explorer:not uploaded (over --godbolt-limit or disabled)

Snippet:

define i64 @pnot_v8i8(i64 %a) {
  %bc = bitcast i64 %a to <8 x i8>
  %not = xor <8 x i8> %bc, splat (i8 -1)
  %res = bitcast <8 x i8> %not to i64
  ret i64 %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: %7:_(s64) = G_BITCAST %6:_(<8 x s8>) (in function: pnot_v8i8)
warning: Instruction selection used fallback path for pnot_v8i8

Occurrences (14):

InputFunctionConfig
rvp-bitcast-const-fold.llpnot_v8i8-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-bitcast-const-fold.llpnot_v8i8-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-bitcast-paired.lladd_v8i8_via_bitcast-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-bitcast-paired.lladd_v8i8_via_bitcast-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb,+d -verify-machineinstrs
rvp-bitcast-paired.lladd_v8i8_via_bitcast-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-ppaireo-w.llinsert_lo_v8i8-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-ppaireo-w.llinsert_hi_v8i8-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-bitcast-const-fold.7f1cad026b.ll (mutant of rvp-bitcast-const-fold.ll)pnot_v8i8-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-bitcast-const-fold.c20adaf840.ll (mutant of rvp-bitcast-const-fold.ll)pnot_v8i8-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-bitcast-paired.3ec74d2311.ll (mutant of rvp-bitcast-paired.ll)add_v8i8_via_bitcast-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-bitcast-paired.7ef2da2734.ll (mutant of rvp-bitcast-paired.ll)add_v8i8_via_bitcast-mtriple=riscv32 -mattr=+experimental-p,+m,+zbb,+d -verify-machineinstrs
rvp-bitcast-paired.cb831cf9fc.ll (mutant of rvp-bitcast-paired.ll)add_v8i8_via_bitcast-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-ppaireo-w.68a907b319.ll (mutant of rvp-ppaireo-w.ll)insert_hi_v8i8-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs
rvp-ppaireo-w.df1920ad0c.ll (mutant of rvp-ppaireo-w.ll)insert_lo_v8i8-mtriple=riscv64 -mattr=+experimental-p,+m,+zbb -verify-machineinstrs

Generated 2026-10-15 08:05 UTC.