#14226: Common Block Elimination pass doesn't eliminate common blocks -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: closed Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.2.1 (CodeGen) | Resolution: fixed | Keywords: newcomer Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #9157 | Differential Rev(s): Phab:D3973, Wiki Page: | Phab:D3999 -------------------------------------+------------------------------------- Comment (by nomeata): I see these two blocks not being commoned up: {{{ c4bx: // global I64[_s3Yp::P64] = stg_MUT_ARR_PTRS_FROZEN0_info; // CmmStore _s3YJ::P64 = _s3Yp::P64; // CmmAssign _s3YJ::P64 = _s3YJ::P64; // CmmAssign I64[Hp - 48] = GHC.Types.I#_con_info; // CmmStore I64[Hp - 40] = _s3Yj::I64; // CmmStore _c4bX::P64 = Hp - 47; // CmmAssign I64[Hp - 32] = GHC.Arr.Array_con_info; // CmmStore P64[Hp - 24] = Database.idatabase1_closure+1; // CmmStore P64[Hp - 16] = _c4bX::P64; // CmmStore P64[Hp - 8] = _s3YJ::P64; // CmmStore I64[Hp] = _s3Yq::I64; // CmmStore _c4bY::P64 = Hp - 31; // CmmAssign _s3YW::P64 = _c4bY::P64; // CmmAssign goto c4b9; // CmmBranch }}} and {{{ c4bD: // global I64[_s3Yp::P64] = stg_MUT_ARR_PTRS_FROZEN0_info; // CmmStore _s3Yy::P64 = _s3Yp::P64; // CmmAssign _s3Yy::P64 = _s3Yy::P64; // CmmAssign I64[Hp - 48] = GHC.Types.I#_con_info; // CmmStore I64[Hp - 40] = _s3Yj::I64; // CmmStore _c4bZ::P64 = Hp - 47; // CmmAssign I64[Hp - 32] = GHC.Arr.Array_con_info; // CmmStore P64[Hp - 24] = Database.idatabase1_closure+1; // CmmStore P64[Hp - 16] = _c4bZ::P64; // CmmStore P64[Hp - 8] = _s3Yy::P64; // CmmStore I64[Hp] = _s3Yq::I64; // CmmStore _c4c0::P64 = Hp - 31; // CmmAssign _s3YW::P64 = _c4c0::P64; // CmmAssign goto c4b9; // CmmBranch }}} Should they? Does maybe the `_s3YJ::P64 = _s3YJ::P64;` throw CBE off? (This is from nofib’s `fem` with commit d871321ce20e – not sure how useful this commit ID is, as it is from a rebasing branch and so far it only lives on Phabricator.) -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14226#comment:16 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler