[llvm] [AMDGPU][SplitModule] Fix unintentional integer division (PR #117586)

[Pierre van Houtryve via llvm-commits]

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@@ -1101,7 +1101,7 @@ void RecursiveSearchSplitting::pickPartition(unsigned Depth, unsigned Idx,
         // Check if the amount of code in common makes it worth it.
         assert(SimilarDepsCost && Entry.CostExcludingGraphEntryPoints);
         const double Ratio =
-            SimilarDepsCost / Entry.CostExcludingGraphEntryPoints;
+            (double)SimilarDepsCost / Entry.CostExcludingGraphEntryPoints;
         assert(Ratio >= 0.0 && Ratio <= 1.0);
         if (LargeFnOverlapForMerge > Ratio) {
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Pierre-vh wrote:

I think this needs to be reversed, so `Ratio > LargeFnOverlapForMerge`

https://github.com/llvm/llvm-project/pull/117586