#14982: LLVM default -mcpu setting inhibits customization -------------------------------------+------------------------------------- Reporter: tommd | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.1 (LLVM) | Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- With GHC 8.4.1 we are now passing a default `-mcpu` selection to llvm. This default is passed regardless of any explicit command line option such as `-optlc=-mcpu=native`. If/when the user explicitly specifies the architecture we now get a failed build. The error message from LLVM is: {{{ llc: for the -mcpu option: may only occur zero or one times! `llc' failed in phase `LLVM Compiler'. (Exit code: 1) }}} This is when compiling with GHC 8.4.1 as such: {{{ ghc-8.4.1 -fforce-recomp -fllvm -optlc=-mcpu=native -O2 tt.hs }} I suggest we either check for a user option of `mcpu` before adding the default or revert this behavior and allow llvm to take it's (optimistic and less portable) default. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14982 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler