Author: pcc Date: Thu Aug 22 12:56:14 2019 New Revision: 369697 URL: http://llvm.org/viewvc/llvm-project?rev=369697&view=rev Log: IR. Change strip* family of functions to not look through aliases.
I noticed another instance of the issue where references to aliases were being replaced with aliasees, this time in InstCombine. In the instance that I saw it turned out to be only a QoI issue (a symbol ended up being missing from the symbol table due to the last reference to the alias being removed, preventing HWASAN from symbolizing a global reference), but it could easily have manifested as incorrect behaviour. Since this is the third such issue encountered (previously: D65118, D65314) it seems to be time to address this common error/QoI issue once and for all and make the strip* family of functions not look through aliases. Includes a test for the specific issue that I saw, but no doubt there are other similar bugs fixed here. As with D65118 this has been tested to make sure that the optimization isn't load bearing. I built Clang, Chromium for Linux, Android and Windows as well as the test-suite and there were no size regressions. Differential Revision: https://reviews.llvm.org/D66606 Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp Modified: cfe/trunk/lib/CodeGen/CGExpr.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExpr.cpp?rev=369697&r1=369696&r2=369697&view=diff ============================================================================== --- cfe/trunk/lib/CodeGen/CGExpr.cpp (original) +++ cfe/trunk/lib/CodeGen/CGExpr.cpp Thu Aug 22 12:56:14 2019 @@ -677,8 +677,7 @@ void CodeGenFunction::EmitTypeCheck(Type // Quickly determine whether we have a pointer to an alloca. It's possible // to skip null checks, and some alignment checks, for these pointers. This // can reduce compile-time significantly. - auto PtrToAlloca = - dyn_cast<llvm::AllocaInst>(Ptr->stripPointerCastsNoFollowAliases()); + auto PtrToAlloca = dyn_cast<llvm::AllocaInst>(Ptr->stripPointerCasts()); llvm::Value *True = llvm::ConstantInt::getTrue(getLLVMContext()); llvm::Value *IsNonNull = nullptr; _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
