digitalmars.D.bugs - [Issue 14498] New: Poor codegen optimization for ranges
- via Digitalmars-d-bugs (56/56) Apr 24 2015 https://issues.dlang.org/show_bug.cgi?id=14498
https://issues.dlang.org/show_bug.cgi?id=14498 Issue ID: 14498 Summary: Poor codegen optimization for ranges Product: D Version: D2 Hardware: x86_64 OS: Linux Status: NEW Severity: normal Priority: P1 Component: DMD Assignee: nobody puremagic.com Reporter: r9shackleford gmail.com dmd and gdc do _very_ poorly on a benchmark featuring D due to what I assume is poor codegen. https://github.com/logicchains/LPATHBench/blob/master/d.d using the "slow"(aka ranges) version, DMD produces code that is 4 times slower. Almost same exact ratios for GDC, so I assume it's due to frontend(?) LDC seems to optimize it away to almost identical performance between "fast" and "slow" version, unsure if it's due to the LLVM optimizations or one of their patches to dmd. dmd 2.067 GC summary for fast version: Number of collections: 1 Total GC prep time: 0 milliseconds Total mark time: 0 milliseconds Total sweep time: 0 milliseconds Total page recovery time: 0 milliseconds Max Pause Time: 0 milliseconds Grand total GC time: 0 milliseconds GC summary: 1 MB, 1 GC 0 ms, Pauses 0 ms < 0 ms dmd 2.067 GC summary for range version: Number of collections: 2711 Total GC prep time: 13 milliseconds Total mark time: 67 milliseconds Total sweep time: 370 milliseconds Total page recovery time: 75 milliseconds Max Pause Time: 0 milliseconds Grand total GC time: 526 milliseconds GC summary: 1 MB, 2711 GC 526 ms, Pauses 80 ms < 0 ms second number is runtime in ms, optimization flags relevant to compilers are enabled. ./dmd_slow 8981 LANGUAGE D 7311 ./dmd_fast 8981 LANGUAGE D 1835 ./gdc_slow 8981 LANGUAGE D 4249 ./gdc_fast 8981 LANGUAGE D 903 ./ldc_slow 8981 LANGUAGE D 999 ./ldc_fast 8981 LANGUAGE D 1078 I marked this as a DMD issue due to LDC producing an expected output despite it being related to phobos. --
Apr 24 2015