[Mlir-commits] [mlir] [mlir][scf] Fix unsigned narrow type trip count calculation (PR #178060)

[Jhalak Patel]

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@@ -391,12 +394,22 @@ std::optional<APInt> constantTripCount(
     return std::nullopt;
   }
   auto &stepCst = maybeStepCst->first;
-  llvm::APInt tripCount = isSigned ? diff.sdiv(stepCst) : diff.udiv(stepCst);
-  llvm::APInt remainder = isSigned ? diff.srem(stepCst) : diff.urem(stepCst);
+  // Create new APSInt instances with explicit signedness to ensure they match
+  llvm::APSInt diffSigned(diff, /*isUnsigned=*/!isSigned);
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jhalakpatel wrote:

Yes the original implementation was correct. I originally thought it would cleaner to encoded the signedness in int type and let the operations (/ or %) dispatch to the correct implementation. 
Now that I look again, later we do `  APInt result = tripCount;`  which seems confusing since we are converting APSInt back to APInt. I will revert to original change here.

https://github.com/llvm/llvm-project/pull/178060