[PATCH] D31242: [ARM] t2_so_imm_neg had a subtle bug in the conversion, and could trigger UB by negating (int)-2147483648. By pure luck, none of the pre-existing tests triggered this; so I'm adding one.

[A. Skrobov via Phabricator via llvm-commits]

tyomitch added inline comments.


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Comment at: lib/Target/ARM/ARMInstrThumb2.td:115
+  int64_t Value = N->getZExtValue();
+  if (Value == 1LL<<31) return false; // INT_MIN cannot be negated
+  Value = -(int)Value;
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rengolin wrote:
> Why not just use INT_MIN?
`getZExtValue()` would have returned the unsigned value, i.e. `(uint64_t)2147483648`


https://reviews.llvm.org/D31242