[Mlir-commits] [mlir] [mlir] Fold ceil/floordiv with negative RHS. (PR #97031)

[Johannes Reifferscheid]

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@@ -855,8 +855,7 @@ static AffineExpr simplifyFloorDiv(AffineExpr lhs, AffineExpr rhs) {
   auto lhsConst = dyn_cast<AffineConstantExpr>(lhs);
   auto rhsConst = dyn_cast<AffineConstantExpr>(rhs);
 
-  // mlir floordiv by zero or negative numbers is undefined and preserved as is.
-  if (!rhsConst || rhsConst.getValue() < 1)
+  if (!rhsConst || rhsConst.getValue() == 0)
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jreiffers wrote:

Thanks for the comment. I don't remember the context of this PR since it's been quite a while. I suspect it was probably related to a fuzzer test that is not public and this PR can therefore be reverted (at least I'm not aware of anything that would actually try to use a negative RHS).

Since this is all UB anyway, I don't think it's particularly urgent / important. Let me know if I'm missing something.

https://github.com/llvm/llvm-project/pull/97031