Uploaded image for project: 'Qt'
  1. Qt
  2. QTBUG-64576

optimize float<->fp16 conversion on aarch64

    XMLWordPrintable

    Details

    • Type: Task
    • Status: Closed
    • Priority: P3: Somewhat important
    • Resolution: Done
    • Affects Version/s: 5.10.0 Beta 4
    • Fix Version/s: 5.10.0 RC
    • Labels:
      None
    • Environment:

      Arm 64-bit

    • Technical Risk:
      Normal

      Description

      https://gcc.gnu.org/onlinedocs/gcc/Half-Precision.html says there are hardware instructions to do this conversion, but only with certain compiler options. I'm not seeing those options in the build log on CI.

      This came up because enabling this platform in CI had the effect of blocking 5.10 integrations for a while. Hopefully doing an explicit cast will be enough: https://codereview.qt-project.org/#/c/211734/ but it probably still would be a good idea to ensure these conversions are done as efficiently as possible.

      The older patch which added initial support is https://codereview.qt-project.org/#/c/185724/

      A build log where I saw the warning (which is an error because of -Werror): https://testresults.qt.io/logs/qt/qtbase/ae93e48e3f326b89adda3ee171d2aff437f9d869/LinuxUbuntu_16_04x86_64LinuxQEMUarm64GCCqtci-linux-Ubuntu-16.04-x86_64-1-e401faDeveloperBuild/2a48a3b7dcb9652b1532a3ad14de7580b5b9b1ee/build_1510903300/log.txt.gz

        Attachments

        No reviews matched the request. Check your Options in the drop-down menu of this sections header.

          Activity

            People

            • Assignee:
              allan.jensen Allan Sandfeld Jensen
              Reporter:
              srutledg Shawn Rutledge
            • Votes:
              0 Vote for this issue
              Watchers:
              2 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved:

                Gerrit Reviews

                There are no open Gerrit changes