[PATCH] D30834: [x86] these aren't the undefs you're looking for (PR32176)

[Craig Topper via Phabricator via cfe-commits]

craig.topper added a comment.

Have you ran the tests all the way through to assembly and made sure we don't regress? If we do regress, I wouldn't hold up fixing this, but we should at least have bugs for what breaks.



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Comment at: lib/CodeGen/CGBuiltin.cpp:7384
   case X86::BI__builtin_ia32_undef512:
-    return UndefValue::get(ConvertType(E->getType()));
+    // The x86 definition of "undef" is not the same as the LLVM definition
+    // (PR32176). We leave the exercise of optimizing away an unnecessary zero
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Do we want to leave a TODO here to maybe do something different when we have freeze?


https://reviews.llvm.org/D30834