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Fix UBSan error with overflowing exponent operator (#1727)

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This commit is contained in:
Rangi
2025-07-07 19:08:26 -04:00
committed by GitHub
parent c9765ec158
commit 1a77667409
5 changed files with 27 additions and 11 deletions
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15
src/opmath.cpp
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@@ -21,20 +21,17 @@ int32_t op_modulo(int32_t dividend, int32_t divisor) {
}
int32_t op_exponent(int32_t base, uint32_t power) {
int32_t result = 1;
uint32_t result = 1;
for (;;) {
for (uint32_t ubase = base; power; power /= 2) {
if (power % 2) {
result *= base;
result = static_cast<uint64_t>(result) * ubase;
}
power /= 2;
if (!power) {
break;
}
base *= base;
ubase = static_cast<uint64_t>(ubase) * ubase;
}
return result;
// Avoid arithmetic overflow runtime error
return result <= INT32_MAX ? result : -static_cast<int32_t>(~result) - 1;
}
int32_t op_shift_left(int32_t value, int32_t amount) {