cmmMiniInlineStmts uses (stmt:stmts)
= stmt : cmmMiniInlineStmts uses stmts
-lookForInline u expr (stmt : rest)
+lookForInline u expr stmts = lookForInline' u expr regset stmts
+ where regset = foldRegsUsed extendRegSet emptyRegSet expr
+
+lookForInline' u expr regset (stmt : rest)
| Just 1 <- lookupUFM (countUses stmt) u, ok_to_inline
= Just (inlineStmt u expr stmt : rest)
| ok_to_skip
- = case lookForInline u expr rest of
+ = case lookForInline' u expr regset rest of
Nothing -> Nothing
Just stmts -> Just (stmt:stmts)
CmmCall{} -> hasNoGlobalRegs expr
_ -> True
- -- We can skip over assignments to other tempoararies, because we
- -- know that expressions aren't side-effecting and temporaries are
- -- single-assignment.
+ -- Expressions aren't side-effecting. Temporaries may or may not
+ -- be single-assignment depending on the source (the old code
+ -- generator creates single-assignment code, but hand-written Cmm
+ -- and Cmm from the new code generator is not single-assignment.)
+ -- So we do an extra check to make sure that the register being
+ -- changed is not one we were relying on. I don't know how much of a
+ -- performance hit this is (we have to create a regset for every
+ -- instruction.) -- EZY
ok_to_skip = case stmt of
CmmNop -> True
- CmmAssign (CmmLocal (LocalReg u' _)) rhs | u' /= u -> True
+ CmmComment{} -> True
+ CmmAssign (CmmLocal r@(LocalReg u' _)) rhs | u' /= u && not (r `elemRegSet` regset) -> True
CmmAssign g@(CmmGlobal _) rhs -> not (g `regUsedIn` expr)
_other -> False