fallback: legalize: G_SMULH s128

Run:main-04ca53e65f-20261014-113325
Kind:fallback
Category:legalize: G_SMULH s128
Occurrences:4 in 2 configs, 1 test files
Snippet from:smulh.ll @smulh_i128 via llvm-extract
Config:-mtriple=riscv32
Local check:reproduces at 04ca53e65f
Compiler Explorer:not uploaded (over --godbolt-limit or disabled)

Snippet:

; Function Attrs: nounwind
define i128 @smulh_i128(i128 %x, i128 %y) #0 {
  %r = call i128 @llvm.smulh.i128(i128 %x, i128 %y)
  ret i128 %r
}

; Function Attrs: nocallback nocreateundeforpoison nofree nosync nounwind speculatable willreturn memory(none)
declare i128 @llvm.smulh.i128(i128, i128) #1

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

Reproduce:

llc -mtriple=riscv32 -global-isel -global-isel-abort=2 -pass-remarks-missed=gisel.* snippet.ll -o -
llc -mtriple=riscv32 -global-isel=0 snippet.ll -o -

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %5:_(s128) = G_SMULH %0:_, %1:_ (in function: smulh_i128)
warning: Instruction selection used fallback path for smulh_i128

Occurrences (4):

InputFunctionConfig
smulh.llsmulh_i128-mtriple=riscv32
smulh.llsmulh_i128-mtriple=riscv64
smulh.281edcea11.ll (mutant of smulh.ll)smulh_i128-mtriple=riscv32
smulh.9a30340399.ll (mutant of smulh.ll)smulh_i128-mtriple=riscv64

Generated 2026-10-15 08:05 UTC.