[PATCH] D90871: [Sema] Fold VLAs to constant arrays in a few more contexts

[Richard Smith - zygoloid via Phabricator via cfe-commits]

rsmith accepted this revision.
rsmith added a comment.
This revision is now accepted and ready to land.

Thanks, that's very clean.



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Comment at: clang/lib/Sema/SemaDecl.cpp:6027
+/// Attempt to fold a variable-sized type to a constant-sized type, returning
+/// true if it we were successful.
+static bool tryToFixVariablyModifiedVarType(Sema &S, TypeSourceInfo *&TInfo,
----------------
Typo "it we"


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Comment at: clang/lib/Sema/SemaDecl.cpp:6899-6901
+    if (D.hasInitializer() && R->isVariablyModifiedType())
+      tryToFixVariablyModifiedVarType(*this, TInfo, R, D.getIdentifierLoc(),
+                                      /*DiagID=*/0);
----------------
Is there a reason to make this C-specific? We support VLAs in C++ as an extension; it'd seem reasonable to do this folding as an extension too, if it's as simple as moving the new code out of the `if (!C++)`.


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Comment at: clang/test/Sema/vla.c:104
+
+void test_fold_to_constant_array() {
+  const int ksize = 4;
----------------
Can you also add a positive test? Eg, a `goto` over one of the folded-to-constant cases, to show that we can jump over those. (As-is, this test ensures that we produce the warning, but not that we actually treat the array variable as not being a VLA.)


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https://reviews.llvm.org/D90871