Added new method #17
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Added new method #17
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amdn
reviewed
Nov 22, 2017
| if (i < 0) { | ||
| *p++ = '-'; | ||
| u = -u; | ||
| u = (uint32_t)(-(int32_t)u); |
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Unary minus applied to a signed integer is undefined behavior for targets that use two's complement when the value is the most negative value (INT_MIN) representable in two's complement, it causes signed overflow. The compiler can assume this never happens. On clang/llvm this doesn't seem to cause a problem, but on gcc with -O3 optimization the compiler takes advantage of this assumption and generates code that gives the wrong answer (or causes segmentation fault).
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