#10699: Regression: panic with custom rewrite rules on primops -------------------------------------+------------------------------------- Reporter: thomie | Owner: Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 7.10.2-rc2 Resolution: invalid | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #10555 | Differential Revisions: -------------------------------------+------------------------------------- Changes (by simonpj): * status: new => closed * resolution: => invalid Comment: As you point out, rule "double commute left" will rewrite {{{ (a *## b) *## (c *## d) ---> (c *## d) *## (a *## b) }}} and the rewrites will go on forever. And that is just what is happening here; it happens in the RHS of rules "double **4". GHE feels free to use rules A,B,C to rewrite the RHS of another rule D. After all, if rule D fires, the RHS would immediately be rewritten by A,B,C, so we may as well do it in advance. So I claim this is a bug in rule "double commute left" and not in HGC. Yell you if you disagree. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10699#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler