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Fixes codegen bug with literal negative zero, fixes #7079 (#7158)

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* Fixes #7079

* Fix handling of neg zero during constant folding
This commit is contained in:
GULPF 2018-01-31 16:29:42 +01:00 • committed by Andreas Rumpf
commit 94038545be
4 changed files with 31 additions and 11 deletions
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16
compiler/jsgen.nim
View file

@ -2284,11 +2284,17 @@ proc gen(p: PProc, n: PNode, r: var TCompRes) =
r.kind = resExpr r.kind = resExpr
of nkFloatLit..nkFloat64Lit: of nkFloatLit..nkFloat64Lit:
let f = n.floatVal let f = n.floatVal
if f != f: r.res = rope"NaN" case classify(f)
elif f == 0.0: r.res = rope"0.0" of fcNaN:
elif f == 0.5 * f: r.res = rope"NaN"
if f > 0.0: r.res = rope"Infinity" of fcNegZero:
else: r.res = rope"-Infinity" r.res = rope"-0.0"
of fcZero:
r.res = rope"0.0"
of fcInf:
r.res = rope"Infinity"
of fcNegInf:
r.res = rope"-Infinity"
else: r.res = rope(f.toStrMaxPrecision) else: r.res = rope(f.toStrMaxPrecision)
r.kind = resExpr r.kind = resExpr
of nkCallKinds: of nkCallKinds:

16
compiler/rodutils.nim
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@ -8,18 +8,22 @@
# #
## Serialization utilities for the compiler. ## Serialization utilities for the compiler.
import strutils import strutils, math
proc c_snprintf(s: cstring; n:uint; frmt: cstring): cint {.importc: "snprintf", header: "<stdio.h>", nodecl, varargs.} proc c_snprintf(s: cstring; n:uint; frmt: cstring): cint {.importc: "snprintf", header: "<stdio.h>", nodecl, varargs.}
proc toStrMaxPrecision*(f: BiggestFloat, literalPostfix = ""): string = proc toStrMaxPrecision*(f: BiggestFloat, literalPostfix = ""): string =
if f != f: case classify(f)
of fcNaN:
result = "NAN" result = "NAN"
elif f == 0.0: of fcNegZero:
result = "-0.0" & literalPostfix
of fcZero:
result = "0.0" & literalPostfix result = "0.0" & literalPostfix
elif f == 0.5 * f: of fcInf:
if f > 0.0: result = "INF" result = "INF"
else: result = "-INF" of fcNegInf:
result = "-INF"
else: else:
when defined(nimNoArrayToCstringConversion): when defined(nimNoArrayToCstringConversion):
result = newString(81) result = newString(81)

1
compiler/semfold.nim
View file

@ -225,6 +225,7 @@ proc evalOp(m: TMagic, n, a, b, c: PNode): PNode =
of mDivF64: of mDivF64:
if getFloat(b) == 0.0: if getFloat(b) == 0.0:
if getFloat(a) == 0.0: result = newFloatNodeT(NaN, n) if getFloat(a) == 0.0: result = newFloatNodeT(NaN, n)
elif getFloat(b).classify == fcNegZero: result = newFloatNodeT(-Inf, n)
else: result = newFloatNodeT(Inf, n) else: result = newFloatNodeT(Inf, n)
else: else:
result = newFloatNodeT(getFloat(a) / getFloat(b), n) result = newFloatNodeT(getFloat(a) / getFloat(b), n)

9
tests/ccgbugs/t7079.nim Normal file
View file

@ -0,0 +1,9 @@
discard """
action: run
targets: '''c js'''
"""
import math
let x = -0.0
doAssert classify(x) == fcNegZero
doAssert classify(1 / -0.0) == fcNegInf