[ThinLTO] Handle chains of aliases
At -O0, globalopt is not run during the compile step, and we can have a
chain of an alias having an immediate aliasee of another alias. The
summaries are constructed assuming aliases in a canonical form
(flattened chains), and as a result only the base object but no
intermediate aliases were preserved.
Fix by adding a pass that canonicalize aliases, which ensures each
alias is a direct alias of the base object.
Reviewers: pcc, davidxl
Subscribers: mehdi_amini, inglorion, eraman, steven_wu, dexonsmith, arphaman, llvm-commits
Differential Revision: https://reviews.llvm.org/D54507
llvm-svn: 350423
diff --git a/llvm/lib/Transforms/Utils/Utils.cpp b/llvm/lib/Transforms/Utils/Utils.cpp
index afd842f..95416de 100644
--- a/llvm/lib/Transforms/Utils/Utils.cpp
+++ b/llvm/lib/Transforms/Utils/Utils.cpp
@@ -26,6 +26,7 @@
void llvm::initializeTransformUtils(PassRegistry &Registry) {
initializeAddDiscriminatorsLegacyPassPass(Registry);
initializeBreakCriticalEdgesPass(Registry);
+ initializeCanonicalizeAliasesLegacyPassPass(Registry);
initializeInstNamerPass(Registry);
initializeLCSSAWrapperPassPass(Registry);
initializeLibCallsShrinkWrapLegacyPassPass(Registry);