[PATCH] D53061: [IndVars] Drop "exact" flag from lshr and udiv when substituting their args

[Sanjoy Das via Phabricator via llvm-commits]

sanjoy accepted this revision.
sanjoy added a comment.
This revision is now accepted and ready to land.

lgtm



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Comment at: lib/Transforms/Utils/SimplifyIndVar.cpp:147
+    if (SE->getSCEV(IVSrc) != SE->getMulExpr(FoldedExpr, SE->getSCEV(D)))
+      MustDropPoisonFlags = true;
   }
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I'd give this a less generic name, like `IsTransformedUDivExact` or something like that.


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Comment at: test/Transforms/IndVarSimplify/drop-exact.ll:8
+; we drop "exact" flag on lshr as we do it.
+define void @test(i32* %p, i64* %p1) {
+; CHECK-LABEL: @test(
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Are there existing tests demonstrating that we do keep `exact` when legal?  If not, would be nice to add one.


https://reviews.llvm.org/D53061