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fixes #23925; VM generates wrong cast for negative enum values (#23951)

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Follow up of #23927 which solves the build error.

This is still only a partial fix as it doesn't take into account
unordered enums. I'll make a separate issue for those.

---------

Co-authored-by: ringabout <43030857+ringabout@users.noreply.github.com>
This commit is contained in:
autumngray
2024-08-27 14:03:56 +02:00
committed by GitHub
parent f09c549d42
commit 540b414c86
2 changed files with 36 additions and 6 deletions
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18
compiler/vmgen.nim
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@@ -900,9 +900,15 @@ proc genCard(c: PCtx; n: PNode; dest: var TDest) =
c.freeTemp(tmp)
proc genCastIntFloat(c: PCtx; n: PNode; dest: var TDest) =
template isSigned(typ: PType): bool {.dirty.} =
typ.kind == tyEnum and firstOrd(c.config, typ) < 0 or
typ.kind in {tyInt..tyInt64}
template isUnsigned(typ: PType): bool {.dirty.} =
typ.kind == tyEnum and firstOrd(c.config, typ) >= 0 or
typ.kind in {tyUInt..tyUInt64, tyChar, tyBool}
const allowedIntegers = {tyInt..tyInt64, tyUInt..tyUInt64, tyChar, tyEnum, tyBool}
var signedIntegers = {tyInt..tyInt64}
var unsignedIntegers = {tyUInt..tyUInt64, tyChar, tyEnum, tyBool}
let src = n[1].typ.skipTypes(abstractRange)#.kind
let dst = n[0].typ.skipTypes(abstractRange)#.kind
let srcSize = getSize(c.config, src)
@@ -914,12 +920,12 @@ proc genCastIntFloat(c: PCtx; n: PNode; dest: var TDest) =
if dest < 0: dest = c.getTemp(n[0].typ)
c.gABC(n, opcAsgnInt, dest, tmp)
if dstSize != sizeof(BiggestInt): # don't do anything on biggest int types
if dst.kind in signedIntegers: # we need to do sign extensions
if isSigned(dst): # we need to do sign extensions
if dstSize <= srcSize:
# Sign extension can be omitted when the size increases.
c.gABC(n, opcSignExtend, dest, TRegister(dstSize*8))
elif dst.kind in unsignedIntegers:
if src.kind in signedIntegers or dstSize < srcSize:
elif isUnsigned(dst):
if isSigned(src) or dstSize < srcSize:
# Cast from signed to unsigned always needs narrowing. Cast
# from unsigned to unsigned only needs narrowing when target
# is smaller than source.
@@ -947,7 +953,7 @@ proc genCastIntFloat(c: PCtx; n: PNode; dest: var TDest) =
if dest < 0: dest = c.getTemp(n[0].typ)
if src.kind == tyFloat32:
c.gABC(n, opcCastFloatToInt32, dest, tmp)
if dst.kind in unsignedIntegers:
if isUnsigned(dst):
# integers are sign extended by default.
# since there is no opcCastFloatToUInt32, narrowing should do the trick.
c.gABC(n, opcNarrowU, dest, TRegister(32))