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^ type(const) now inverts "enough" bits

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^ signed(const) becomes illegal
^ unsigned(const) becomes legal

R=r
OCL=26697
CL=26697
This commit is contained in:
Ken Thompson 2009-03-24 16:40:38 -07:00
parent 85e014a27e
commit b8be809c10
3 changed files with 31 additions and 3 deletions
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32
src/cmd/gc/const.c
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@ -282,8 +282,9 @@ evconst(Node *n)
Node *nl, *nr; Node *nl, *nr;
int32 len; int32 len;
String *str; String *str;
int wl, wr, lno; int wl, wr, lno, et;
Val v; Val v;
Mpint b;
nl = n->left; nl = n->left;
if(nl == N || nl->type == T) if(nl == N || nl->type == T)
@ -541,7 +542,34 @@ unary:
mpnegfix(v.u.xval); mpnegfix(v.u.xval);
break; break;
case TUP(OCOM, CTINT): case TUP(OCOM, CTINT):
mpcomfix(v.u.xval); et = Txxx;
if(nl->type != T)
et = nl->type->etype;
// calculate the mask in b
// result will be (a ^ mask)
switch(et) {
default:
mpmovecfix(&b, -1);
break;
case TINT8:
case TINT16:
case TINT32:
case TINT64:
case TINT:
et++; // convert to unsigned
// fallthrough
case TUINT8:
case TUINT16:
case TUINT32:
case TUINT64:
case TUINT:
case TUINTPTR:
mpmovefixfix(&b, maxintval[et]);
break;
}
mpxorfixfix(v.u.xval, &b);
break; break;
case TUP(OPLUS, CTFLT): case TUP(OPLUS, CTFLT):

2
test/const1.go
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@ -39,7 +39,7 @@ var (
b3 = Uint8 - Uint8; // OK b3 = Uint8 - Uint8; // OK
b4 = Uint8 - Uint8 - Uint8; // ERROR "overflow" b4 = Uint8 - Uint8 - Uint8; // ERROR "overflow"
b5 = uint8(^0); // ERROR "overflow" b5 = uint8(^0); // ERROR "overflow"
b6 = ^uint8(0); // ERROR "overflow" b6 = ^uint8(0); // OK
b7 = uint8(Minus1); // ERROR "overflow" b7 = uint8(Minus1); // ERROR "overflow"
b8 = uint8(int8(-1)); // ERROR "overflow" b8 = uint8(int8(-1)); // ERROR "overflow"
b8a = uint8(-1); // ERROR "overflow" b8a = uint8(-1); // ERROR "overflow"

0
test/bugs/bug115.go → test/fixedbugs/bug115.go
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