[PATCH] D85865: [ConstProp] Handle insertelement constants

[Arthur Eubanks via Phabricator via llvm-commits]

aeubanks added inline comments.


================
Comment at: llvm/lib/IR/ConstantFold.cpp:858
+      if (const auto *IEIdx = dyn_cast<ConstantInt>(CE->getOperand(2))) {
+        if (IEIdx->equalsInt(CIdx->getZExtValue())) {
+          if (auto *IEValue = dyn_cast<Constant>(CE->getOperand(1)))
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efriedma wrote:
> aeubanks wrote:
> > efriedma wrote:
> > > Oh, also, please avoid using getZExtValue() on constants that don't have a known width; it asserts the number is less than 2^64.  Unfortunately, there isn't any convenient way to do this comparison at the moment; I guess you could use APSInt::isSameValue.
> > Is APInt::eq() good?
> IDIdx and CIdx might not have the same bitwidth, I think; the index of an insertelement/extractelement can have any type.  APInt::eq asserts if the widths aren't equal.
Ah yes, I changed one of the types in the new test and repro'd. Now using APSInt::isSameValue().


Repository:
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  https://reviews.llvm.org/D85865/new/

https://reviews.llvm.org/D85865