fallback: legalize: G_CTLZ_ZERO_POISON s64,s256

Run:main-04ca53e65f-20261014-105623
Kind:fallback
Category:legalize: G_CTLZ_ZERO_POISON s64,s256 NEW
Occurrences:1 in 1 configs, 1 test files
Snippet from:div_minsize.e7a5a85e25.ll (mutant of div_minsize.ll) @i256_sdiv via llvm-extract
Config:-mtriple=riscv64 -mattr=+m -verify-machineinstrs
Local check:reproduces at 04ca53e65f
Compiler Explorer:not uploaded (over --godbolt-limit or disabled)

Snippet:

@G.1 = external global i256
@G.2 = external global i256

; Function Attrs: minsize nounwind
define i256 @i256_sdiv(i256 %arg0) #0 {
  %div = sdiv i256 %arg0, 4
  br label %BB

BB:                                               ; preds = %0
  %LGV1 = load i256, ptr @G.1, align 4
  %B = urem i256 %div, %LGV1
  store i256 %B, ptr @G.2, align 4
  ret i256 %div
}

attributes #0 = { minsize nounwind }

Reproduce:

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

Local llc output:

remark: <unknown>:0:0: unable to legalize instruction: %1185:_(s64) = G_CTLZ_ZERO_POISON %10:_(s256) (in function: i256_sdiv)
warning: Instruction selection used fallback path for i256_sdiv

Occurrences (1):

InputFunctionConfig
div_minsize.e7a5a85e25.ll (mutant of div_minsize.ll)i256_sdiv-mtriple=riscv64 -mattr=+m -verify-machineinstrs

Generated 2026-10-15 08:05 UTC.