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| author | LemonBoy <thatlemon@gmail.com> | 2019-04-26 15:57:47 +0200 |
|---|---|---|
| committer | Andrew Kelley <andrew@ziglang.org> | 2019-04-26 14:24:35 -0400 |
| commit | 9ec4ccc68f6473ce4f02fc5d2b87ad92e2eb555a (patch) | |
| tree | e11ad31594fe66fcfa449960f4b128ec9315d93e /src/bigint.cpp | |
| parent | 4df2f3d74f140ae6a60dc33d3e0fb7b25f29d5b9 (diff) | |
| download | zig-9ec4ccc68f6473ce4f02fc5d2b87ad92e2eb555a.tar.gz zig-9ec4ccc68f6473ce4f02fc5d2b87ad92e2eb555a.zip | |
Do not invoke UB in BigInt shr operations
Shifting a value of type T by an amount that's greater or equal to the
size of the type itself is UB.
Spotted by @tgschultz
Diffstat (limited to 'src/bigint.cpp')
| -rw-r--r-- | src/bigint.cpp | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/bigint.cpp b/src/bigint.cpp index dcd9dfc0bd..da53a2b129 100644 --- a/src/bigint.cpp +++ b/src/bigint.cpp @@ -1395,7 +1395,7 @@ void bigint_shr(BigInt *dest, const BigInt *op1, const BigInt *op2) { uint64_t shift_amt = bigint_as_unsigned(op2); if (op1->digit_count == 1) { - dest->data.digit = op1_digits[0] >> shift_amt; + dest->data.digit = (shift_amt < 64) ? op1_digits[0] >> shift_amt : 0; dest->digit_count = 1; dest->is_negative = op1->is_negative; bigint_normalize(dest); |