[Backport llvm-project#97148][AArch64] Avoid overflow when using shl lower mul #174
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Fixes llvm#97147. Transforming `(mul x, -(2^(N-M) - 1) * 2^M)` to `(sub (shl x, M), (shl x, N))` will cause overflow when N is 32 and M is 31. I still added checks for all scenarios, even other scenarios, don't seem to cause overflow. (cherry picked from commit 4a96803)
nikic
approved these changes
Jun 30, 2024
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Backport llvm#97148.
For rust-lang/rust#112548.