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Update shift left that might cause ub

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A few shift lefts cause ub because of `(1 << n)` where `n` is 31. 
The constant 1 is signed causing ub. Initially my fix was to do `(1U << n)` however, I have seen the pattern `((U32)1 << n)` elsewhere in the file so decided to follow this.

Caught by ubsan racketcs.
original commit: a902c9ab67010f521f786e2027d4e197d78975a4
This commit is contained in:
Paulo Matos 2019-06-06 08:56:50 +02:00 committed by Matthew Flatt
parent a0fea7f0a8
commit af63b73bad
1 changed files with 3 additions and 3 deletions
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6
c/number.c
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@ -1671,7 +1671,7 @@ static ptr big_logbitp(n, x, xl, xs) ptr x; iptr n, xl; IBOOL xs; {
if (i < 0) return Sfalse;
n = n % bigit_bits;
return Sboolean(BIGIT(x,i) & (1 << n));
return Sboolean(BIGIT(x,i) & ((U32)1 << n));
} else {
bigit xb;
@ -1681,7 +1681,7 @@ static ptr big_logbitp(n, x, xl, xs) ptr x; iptr n, xl; IBOOL xs; {
xp = &BIGIT(x,xl); xb = 1;
for (i = xl; ; i -= 1) {
bigit t1 = *--xp, t2 = t1 - xb;
if (n < bigit_bits) return Sboolean(~t2 & (1 << n));
if (n < bigit_bits) return Sboolean(~t2 & ((U32)1 << n));
xb = t2 > t1;
n -= bigit_bits;
}
@ -1804,7 +1804,7 @@ static ptr big_logbit1(tc, origx, n, x, xl, xs) ptr tc, origx, x; iptr n, xl; IB
*--zp = x1;
n -= bigit_bits;
}
*--zp = x1 | (1 << n);
*--zp = x1 | ((U32)1 << n);
for (; i > 0; i -= 1) *--zp = *--xp;
return copy_normalize(zp, zl, 0);
} else if (yl > xl) {