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fixes #3882

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This commit is contained in:
Andreas Rumpf 2016-05-28 17:43:47 +02:00
commit 426306eeb4
2 changed files with 59 additions and 31 deletions
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80
lib/system.nim
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@ -3042,34 +3042,6 @@ when not defined(JS): #and not defined(nimscript):
{.pop.} # stacktrace
when not defined(nimscript):
proc likely*(val: bool): bool {.importc: "likely", nodecl, nosideeffect.}
## Hints the optimizer that `val` is likely going to be true.
##
## You can use this proc to decorate a branch condition. On certain
## platforms this can help the processor predict better which branch is
## going to be run. Example:
##
## .. code-block:: nim
## for value in inputValues:
## if likely(value <= 100):
## process(value)
## else:
## echo "Value too big!"
proc unlikely*(val: bool): bool {.importc: "unlikely", nodecl, nosideeffect.}
## Hints the optimizer that `val` is likely going to be false.
##
## You can use this proc to decorate a branch condition. On certain
## platforms this can help the processor predict better which branch is
## going to be run. Example:
##
## .. code-block:: nim
## for value in inputValues:
## if unlikely(value > 100):
## echo "Value too big!"
## else:
## process(value)
proc rawProc*[T: proc](x: T): pointer {.noSideEffect, inline.} =
## retrieves the raw proc pointer of the closure `x`. This is
## useful for interfacing closures with C.
@ -3137,6 +3109,58 @@ proc quit*(errormsg: string, errorcode = QuitFailure) {.noReturn.} =
{.pop.} # checks
{.pop.} # hints
when not defined(JS):
proc likely_proc(val: bool): bool {.importc: "likely", nodecl, nosideeffect.}
proc unlikely_proc(val: bool): bool {.importc: "unlikely", nodecl, nosideeffect.}
template likely*(val: bool): bool =
## Hints the optimizer that `val` is likely going to be true.
##
## You can use this template to decorate a branch condition. On certain
## platforms this can help the processor predict better which branch is
## going to be run. Example:
##
## .. code-block:: nim
## for value in inputValues:
## if likely(value <= 100):
## process(value)
## else:
## echo "Value too big!"
##
## On backends without branch prediction (JS and the nimscript VM), this
## template will not affect code execution.
when nimvm:
val
else:
when defined(JS):
val
else:
likely_proc(val)
template unlikely*(val: bool): bool =
## Hints the optimizer that `val` is likely going to be false.
##
## You can use this proc to decorate a branch condition. On certain
## platforms this can help the processor predict better which branch is
## going to be run. Example:
##
## .. code-block:: nim
## for value in inputValues:
## if unlikely(value > 100):
## echo "Value too big!"
## else:
## process(value)
##
## On backends without branch prediction (JS and the nimscript VM), this
## template will not affect code execution.
when nimvm:
val
else:
when defined(JS):
val
else:
unlikely_proc(val)
proc `/`*(x, y: int): float {.inline, noSideEffect.} =
## integer division that results in a float.
result = toFloat(x) / toFloat(y)