[DA] Fix Strong SIV test for symbolic coefficients and deltas (#149977) Fixes GitHub issue #149977 where Strong SIV test incorrectly rejected dependencies with symbolic coefficients and deltas due to overly conservative bound checking. Root cause: The bound constraint check |Delta| > UpperBound * |Coeff| would prematurely reject dependencies when SCEV couldn't prove the relationship definitively for symbolic expressions, preventing the analysis from reaching the division logic. Solution: 1. Make bound check less conservative for symbolic expressions by adding runtime assumptions when SCEV cannot determine the relationship. 2. Enable symbolic division using SE->getUDivExactExpr for Delta/Coeff. 3. Add runtime assumptions where symbolic division cannot be computed. This enables precise dependence analysis for cases like: - Coefficient: -k (symbolic) - Delta: -(2*k + 1) (symbolic) - Distance: (2*k + 1)/k (computed symbolically) Test case validates: - When k = -1: distance = 1, clear flow dependence detected. - Runtime assumptions ensure bounds are satisfied.
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