[PATCH] D4276: Added llvm.is.constant intrinsic

[Bill Wendling via Phabricator via llvm-commits]

void added inline comments.


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Comment at: llvm/docs/LangRef.rst:14432-14433
+The result of the intrinsic will depend on what optimisations are
+run. In particular, note that it will always be false if constant
+folding is not done.
+
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This is true only for expressions that evaluate to constants not immediates, right?

Should you also mention that if a function with llvm.is.constant() is inlined, any constants fed into the inlined function may cause llvm.is.constant() to return true? (or something to that affect)


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Comment at: llvm/include/llvm/IR/Intrinsics.td:838
+// Intrinsic to detect whether its argument is a constant.
+def int_is_constant : Intrinsic<[llvm_i1_ty], [llvm_any_ty], [IntrNoMem], "llvm.is.constant">;
+
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80-columns?


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Comment at: llvm/lib/Transforms/Scalar/SCCP.cpp:1176
            AI != E; ++AI) {
+        if (AI->get()->getType()->isStructTy())
+          return markOverdefined(I); // Can't handle struct args.
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This seems unrelated. Was it meant to be in this patch? If so, could you comment that it's specifically related to llvm.is.constant()?


https://reviews.llvm.org/D4276