[PATCH] D12073: Make ScalarEvolution::isKnownPredicate a little smarter

[Sanjoy Das via llvm-commits]

sanjoy requested changes to this revision.
This revision now requires changes to proceed.

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Comment at: lib/Analysis/ScalarEvolution.cpp:7357
@@ +7356,3 @@
+    return false;
+  if (LAR->getLoop() != RAR->getLoop())
+    return false;
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Optional: I'd have just folded the null checks into this condition.

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Comment at: lib/Analysis/ScalarEvolution.cpp:7367
@@ +7366,3 @@
+  auto CheckWrap = [Pred](const SCEVAddRecExpr *AR) -> bool {
+    if (ICmpInst::getSignedPredicate(Pred) == Pred) {
+      if (!AR->getNoWrapFlags(SCEV::FlagNSW))
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I'd use `CmpInst::isSigned(Pred)` here.

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Comment at: lib/Analysis/ScalarEvolution.cpp:7368
@@ +7367,3 @@
+    if (ICmpInst::getSignedPredicate(Pred) == Pred) {
+      if (!AR->getNoWrapFlags(SCEV::FlagNSW))
+        return false;
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Why not `return AR->getNoWrapFlags(SCEV::FlagNSW);` here, and `return AR->getNoWrapFlags(SCEV::FlagNUW);` in the `else` block?


http://reviews.llvm.org/D12073