[llvm-branch-commits] [llvm] [DA] Fix Strong SIV test for symbolic coefficients and deltas (#149977) (PR #157738)

[Sushant Gokhale via llvm-branch-commits]

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@@ -1249,10 +1249,33 @@ bool DependenceInfo::strongSIVtest(const SCEV *Coeff, const SCEV *SrcConst,
         SE->isKnownNonNegative(Coeff) ? Coeff : SE->getNegativeSCEV(Coeff);
     const SCEV *Product = SE->getMulExpr(UpperBound, AbsCoeff);
     if (isKnownPredicate(CmpInst::ICMP_SGT, AbsDelta, Product)) {
-      // Distance greater than trip count - no dependence
-      ++StrongSIVindependence;
-      ++StrongSIVsuccesses;
-      return true;
+      // Check if this involves symbolic expressions where we might be too
+      // conservative.
+      if (isa<SCEVUnknown>(Delta) || isa<SCEVUnknown>(Coeff) ||
+          !isa<SCEVConstant>(AbsDelta) || !isa<SCEVConstant>(Product)) {
+        // For symbolic expressions, add runtime assumption rather than
+        // rejecting.
+        const SCEVPredicate *BoundPred =
+            SE->getComparePredicate(ICmpInst::ICMP_SLE, AbsDelta, Product);
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sushgokh wrote:

push this inside if(){...}

https://github.com/llvm/llvm-project/pull/157738