#11792: Optimised unsafe FFI call can get wrong argument -------------------------------------+------------------------------------- Reporter: Szunti | Owner: Type: bug | Status: new Priority: high | Milestone: Component: Compiler | Version: 7.10.3 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Incorrect result | Unknown/Multiple at runtime | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by hsyl20): I have made a first patch: https://phabricator.haskell.org/D2263 The result looks better (even if a little bit suboptimal): {{{#!nasm movq 8(%rbp),%rax xorl %ecx,%ecx xorl %edx,%edx movl $7457,%esi movl $255,%edi ; inlined code not using %esi/%rsi ; ... movq %rcx,%rdi ; suboptimal (could be xorq %rdi, %rdi) movq %rsi,%rcx ; suboptimal (could be movq %rsi, %rdx directly) movq %rbx,%rsi ; suboptimal (could be xorq %rsi, %rsi) movq %rcx,%rdx movq %rax,%rcx subq $8,%rsp xorl %eax,%eax call third_arg }}} The patch doesn't handle pushed args yet. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/11792#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler