[llvm] [DA] Check for overflow in strong SIV test (PR #166223)

[Ryotaro Kasuga via llvm-commits]

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@@ -12,19 +12,24 @@
 ;     A[2*i - 4] = 2;
 ; }
 ;
-; FIXME: DependenceAnalysis currently detects no dependency between the two
-; stores, but it does exist. For example, each store will access A[0] when i
-; is 1 and 2 respectively.
-; The root cause is that the product of the BTC and the coefficient
-; ((1LL << 62) - 1 and 2) overflows in a signed sense.
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kasuga-fj wrote:

This test is not the same as `@strongSIV11`. It doesn't contain the access to `A[i]`. If you want to modify it, please follow the above pseudo code.

https://github.com/llvm/llvm-project/pull/166223