[PATCH] D153414: [LLVM] Do not speculate convergent calls

[Sameer Sahasrabuddhe via Phabricator via llvm-commits]

sameerds abandoned this revision.
sameerds added a comment.

Abandoning. I agree with relying on attribute speculatable. If we figure out the conditions that make a convergent call speculatable, then at that time, we should use the appropriate attribute to record that fact. On the other hand, if speculation of a convergent call is dependent on the surrounding control flow, then we will probably have to do it as a separate optimization.



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Comment at: llvm/lib/Analysis/ValueTracking.cpp:6006-6012
+    if (CI->isConvergent())
+      return false;
 
     // The called function could have undefined behavior or side-effects, even
     // if marked readnone nounwind.
+    const Function *Callee = CI->getCalledFunction();
     return Callee && Callee->isSpeculatable();
----------------
arsenm wrote:
> Should go through the CallBase rather than separately checking the callee and call site attributes. Also you're missing invokes
Just below, all the other "call-like" instructions are simply assumed to be not safe for speculation. 


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https://reviews.llvm.org/D153414