Improving error message in CmmLint

diff --git a/compiler/cmm/CmmLint.hs b/compiler/cmm/CmmLint.hs
index 80ad9ef..632337f 100644 (file)
--- a/compiler/cmm/CmmLint.hs
+++ b/compiler/cmm/CmmLint.hs
@@ -63,7 +63,7 @@ lintCmmExpr expr@(CmmMachOp op args) = do
   mapM_ lintCmmExpr args
   if map cmmExprRep args == machOpArgReps op
        then cmmCheckMachOp op args
-       else cmmLintMachOpErr expr
+       else cmmLintMachOpErr expr (map cmmExprRep args) (machOpArgReps op)
 lintCmmExpr (CmmRegOff reg offset)
   = lintCmmExpr (CmmMachOp (MO_Add rep) 
                [CmmReg reg, CmmLit (CmmInt (fromIntegral offset) rep)])
@@ -149,9 +149,12 @@ addLintInfo info thing = CmmLint $
        Left err -> Left (hang info 2 err)
        Right a  -> Right a
 
-cmmLintMachOpErr :: CmmExpr -> CmmLint a
-cmmLintMachOpErr expr = cmmLintErr (text "in MachOp application: " $$ 
-                                       nest 2 (pprExpr expr))
+cmmLintMachOpErr :: CmmExpr -> [MachRep] -> [MachRep] -> CmmLint a
+cmmLintMachOpErr expr argsRep opExpectsRep
+     = cmmLintErr (text "in MachOp application: " $$ 
+                                       nest 2 (pprExpr expr) $$
+                                       (text "op is expecting: " <+> ppr opExpectsRep) $$
+                                       (text "arguments provide: " <+> ppr argsRep))
 
 cmmLintAssignErr :: CmmStmt -> CmmLint a
 cmmLintAssignErr stmt = cmmLintErr (text "in assignment: " $$