fallback: legalize: G_MUL <2 x s64>

Run:explore-04ca53e65f-20261014-114124
Kind:fallback
Category:legalize: G_MUL <2 x s64> NEW
Occurrences:1 in 1 configs, 1 test files
Snippet from:rv64p.6b5eb1b7bd.ll (mutant of rv64p.ll) @macc_w00_commute via llvm-extract
Config:-mtriple=riscv64 -mattr=+experimental-p,+zbb,+m -verify-machineinstrs
Local check:reproduces at 04ca53e65f
Compiler Explorer:not uploaded (over --godbolt-limit or disabled)

Snippet:

@G = external global <2 x i64>
@G.1 = external global <2 x i64>

; Function Attrs: nounwind
define i64 @macc_w00_commute(i64 %rd, i32 %a, i32 %b) #0 {
  %LGV = load <2 x i64>, ptr @G, align 16
  %B = mul <2 x i64> splat (i64 9223372036854775807), %LGV
  %aext = sext i32 %a to i64
  %bext = sext i32 %b to i64
  %mul = mul i64 %aext, %bext
  %result = add i64 %mul, %rd
  store <2 x i64> %B, ptr @G.1, align 16
  ret i64 %result
}

attributes #0 = { nounwind }

Reproduce:

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

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %9:_(<2 x s64>) = G_MUL %7:_, %5:_ (in function: macc_w00_commute)
warning: Instruction selection used fallback path for macc_w00_commute

Occurrences (1):

InputFunctionConfig
rv64p.6b5eb1b7bd.ll (mutant of rv64p.ll)macc_w00_commute-mtriple=riscv64 -mattr=+experimental-p,+zbb,+m -verify-machineinstrs

Generated 2026-10-15 08:05 UTC.