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fixes #25719; optimizes setLenSeqCall for orc (#25721)

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fixes #25719

This pull request updates the logic for resizing sequences during
certain copy operations in the `compiler/liftdestructors.nim` file. The
main improvement is that the code now distinguishes between regular and
uninitialized resizing based on whether the sequence's element type
supports bulk memory copying, which can lead to more efficient code
generation.

**Improvements to sequence resizing and copying logic:**

* Modified `setLenSeqCall` to accept a `noinit` parameter, allowing it
to choose between `setLen` and `setLenUninit` operations, and to select
the appropriate magic for each case.
* Updated `fillSeqOp` to determine if bulk memory copy is supported and,
if so, call `setLenSeqCall` with `noinit = true` and perform a bulk
copy; otherwise, it defaults to element-wise copying. This logic is now
applied in both relevant locations in the function.
[[1]](diffhunk://#diff-456118dde9a4e21f1b351fd72504d62fc16e9c30354dbb9a3efcb95a29067863L646-R650)
[[2]](diffhunk://#diff-456118dde9a4e21f1b351fd72504d62fc16e9c30354dbb9a3efcb95a29067863L661-R666)
This commit is contained in:
ringabout
2026-04-09 17:11:06 +08:00
committed by GitHub
parent fa6b754dbc
commit 188aa1714e
1 changed files with 10 additions and 6 deletions
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16
compiler/liftdestructors.nim
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@@ -592,10 +592,12 @@ proc setLenStrCall(c: var TLiftCtx; x, y: PNode): PNode =
result = genBuiltin(c, mSetLengthStr, "setLen", x) # genAddr(g, x))
result.add lenCall
proc setLenSeqCall(c: var TLiftCtx; t: PType; x, y: PNode): PNode =
proc setLenSeqCall(c: var TLiftCtx; t: PType; x, y: PNode; noinit = false): PNode =
let lenCall = genBuiltin(c, mLengthSeq, "len", y)
lenCall.typ = getSysType(c.g, x.info, tyInt)
var op = getSysMagic(c.g, x.info, "setLen", mSetLengthSeq)
let name = if noinit: "setLenUninit" else: "setLen"
let magic = if noinit: mSetLengthSeqUninit else: mSetLengthSeq
var op = getSysMagic(c.g, x.info, name, magic)
op = instantiateGeneric(c, op, t, t)
result = newTree(nkCall, newSymNode(op, x.info), x, lenCall)
@@ -643,8 +645,9 @@ proc genBulkCopySeq(c: var TLiftCtx; t: PType; body, x, y: PNode) =
proc fillSeqOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
case c.kind
of attachedDup:
body.add setLenSeqCall(c, t, x, y)
if supportsCopyMem(t.elementType):
let bulkCopy = supportsCopyMem(t.elementType)
body.add setLenSeqCall(c, t, x, y, noinit = bulkCopy)
if bulkCopy:
genBulkCopySeq(c, t, body, x, y)
else:
forallElements(c, t, body, x, y)
@@ -658,8 +661,9 @@ proc fillSeqOp(c: var TLiftCtx; t: PType; body, x, y: PNode) =
# This is usually more efficient than a destroy/create pair.
# For trivially copyable types, use bulk copyMem instead of element loop.
checkSelfAssignment(c, t, body, x, y)
body.add setLenSeqCall(c, t, x, y)
if supportsCopyMem(t.elementType):
let bulkCopy = supportsCopyMem(t.elementType)
body.add setLenSeqCall(c, t, x, y, noinit = bulkCopy)
if bulkCopy:
genBulkCopySeq(c, t, body, x, y)
else:
forallElements(c, t, body, x, y)