Simon Jakobi pushed to branch wip/sjakobi/T26964 at Glasgow Haskell Compiler / GHC

Commits:

• 7ec0dc61
  by Simon Jakobi at 2026-06-03T16:42:48+02:00

  StgToCmm: only record primop name when -fcheck-prim-bounds is on
  
  Recording the primop name for bounds-check error messages allocated a name
  thunk and updated FCodeState on every primop compilation. Guard it on the flag
  so the common unchecked case pays nothing.
  
  Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
  

1 changed file:

• compiler/GHC/StgToCmm/Prim.hs

Changes:

      -- if the result type isn't explicitly given, we directly use the

      -- result type of the primop.

      res_ty = fromMaybe (primOpResultType primop) mres_ty

-  -- Record the primop name so that any -fcheck-prim-bounds failure handler

-  -- emitted while compiling it can name it in the error message.

-  withCurrentPrimOpName (occNameString (primOpOcc primop)) (f res_ty)

+  -- When -fcheck-prim-bounds is on, record the primop name so that any

+  -- bounds-check failure handler emitted while compiling it can name it in the

+  -- error message. Guarded by the flag so that the common (unchecked) case pays

+  -- nothing: no name thunk, no FCodeState update.

+  if stgToCmmDoBoundsCheck cfg

+    then withCurrentPrimOpName (occNameString (primOpOcc primop)) (f res_ty)

+    else f res_ty

 externalPrimop :: PrimOp -> [CmmExpr] -> PrimopCmmEmit

 externalPrimop primop args = outOfLinePrimop (callExternalPrimop primop args)