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fix regression in semfold for old right shift (#11477)

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Arne Döring 2019-06-12 09:26:30 +02:00 • committed by Andreas Rumpf
commit e4d0f4fee0
1 changed files with 16 additions and 1 deletions
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17
compiler/semfold.nim
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@ -248,8 +248,23 @@ proc evalOp(m: TMagic, n, a, b, c: PNode; g: ModuleGraph): PNode =
result = doAndFit(newIntNodeT(`shl`(getInt(a), getInt(b)), n, g)) result = doAndFit(newIntNodeT(`shl`(getInt(a), getInt(b)), n, g))
else: internalError(g.config, n.info, "constant folding for shl") else: internalError(g.config, n.info, "constant folding for shl")
of mShrI: of mShrI:
let a = cast[uint64](getInt(a)) var a = cast[uint64](getInt(a))
let b = cast[uint64](getInt(b)) let b = cast[uint64](getInt(b))
# To support the ``-d:nimOldShiftRight`` flag, we need to mask the
# signed integers to cut off the extended sign bit in the internal
# representation.
if 0'u64 < b: # do not cut off the sign extension, when there is
# no bit shifting happening.
case skipTypes(n.typ, abstractRange).kind
of tyInt8: a = a and 0xff'u64
of tyInt16: a = a and 0xffff'u64
of tyInt32: a = a and 0xffffffff'u64
of tyInt:
if g.config.target.intSize == 4:
a = a and 0xffffffff'u64
else:
# unsigned and 64 bit integers don't need masking
discard
let c = cast[BiggestInt](a shr b) let c = cast[BiggestInt](a shr b)
result = newIntNodeT(c, n, g) result = newIntNodeT(c, n, g)
of mAshrI: of mAshrI: