matchFailure.hs

compiler\nativeGen\X86\CodeGen.hs:169:1: warning: [-Wincomplete-patterns]
    Pattern match(es) are non-exhaustive
    In an equation for `verifyBasicBlock':
        Patterns not matched: _ :: [Instr]
    |
169 | verifyBasicBlock instrs


-- Verifying basic blocks is cheap, but not cheap enough to enable it unconditionally.
verifyBasicBlock :: [Instr] -> ()
verifyBasicBlock instrs
  | debugIsOn     = go False instrs
  | not debugIsOn = ()
  where
    go _     [] = ()
    go atEnd (i:instr)
        = case i of
            -- Start a new basic block
            NEWBLOCK {} -> go False instr
            -- Calls are not viable block terminators
            CALL {}     | atEnd -> faultyBlockWith i
                        | not atEnd -> go atEnd instr
            -- All instructions ok, check if we reached the end and continue.
            _ | not atEnd -> go (isJumpishInstr i) instr
              -- Only jumps allowed at the end of basic blocks.
              | otherwise -> if isJumpishInstr i
                                then go True instr
                                else faultyBlockWith i
    faultyBlockWith i
        = pprPanic "Non control flow instructions after end of basic block."
                   (ppr i <+> text "in:" $$ vcat (map ppr instrs))