Skip to content

GitLab

  • Projects
  • Groups
  • Snippets
  • Help
    • Loading...
  • Help
    • Help
    • Support
    • Community forum
    • Submit feedback
  • Sign in / Register
GHC
GHC
  • Project overview
    • Project overview
    • Details
    • Activity
    • Releases
  • Repository
    • Repository
    • Files
    • Commits
    • Branches
    • Tags
    • Contributors
    • Graph
    • Compare
    • Locked Files
  • Issues 4,248
    • Issues 4,248
    • List
    • Boards
    • Labels
    • Service Desk
    • Milestones
    • Iterations
  • Merge Requests 397
    • Merge Requests 397
  • Requirements
    • Requirements
    • List
  • CI / CD
    • CI / CD
    • Pipelines
    • Jobs
    • Schedules
  • Security & Compliance
    • Security & Compliance
    • Dependency List
    • License Compliance
  • Operations
    • Operations
    • Incidents
    • Environments
  • Analytics
    • Analytics
    • CI / CD
    • Code Review
    • Insights
    • Issue
    • Repository
    • Value Stream
  • Wiki
    • Wiki
  • Snippets
    • Snippets
  • Members
    • Members
  • Collapse sidebar
  • Activity
  • Graph
  • Create a new issue
  • Jobs
  • Commits
  • Issue Boards
  • Glasgow Haskell Compiler
  • GHCGHC
  • Issues
  • #5414

Closed
Open
Opened Aug 14, 2011 by tibbe@trac-tibbe

Add unsafeShift to Data.Bits

shiftL and shiftR introduce an extra branch to check for overflows (i.e. shifts with an amount larger than 32/64). This branch gets removed if the shift amount is statically known, but otherwise leaves a branch in the optimized code, slowing down bit manipulation code.

unsafeShiftL and unsafeShiftR translate directly to the underlying hardware operation (which is undefined for shift amount larger than the architectures word size).

Trac metadata
Trac field Value
Version 7.2.1
Type FeatureRequest
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component libraries/base
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture
Assignee
Assign to
7.4.1
Milestone
7.4.1
Assign milestone
Time tracking
None
Due date
None
Reference: ghc/ghc#5414