[llvm] [VPlan] First step towards VPlan cost modeling (LegacyCM in CostCtx) (PR #92555)

[via llvm-commits]

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@@ -1472,3 +1555,16 @@ VPValue *vputils::getOrCreateVPValueForSCEVExpr(VPlan &Plan, const SCEV *Expr,
   Plan.addSCEVExpansion(Expr, Expanded);
   return Expanded;
 }
+
+bool vputils::isUniformCompare(VPValue *Cond) {
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ayalz wrote:

This checks not only if Cond is a (uniform) compare, but also if it's live-in, and the negation of a uniform compare or live-in. In general, it should probably detect uniform i1 VPValues, to infer that branches using them are uniform, and may be computed by compares and/or boolean operators. I.e., `isUniformBoolean()`?

https://github.com/llvm/llvm-project/pull/92555