PMB: Run the whole-program-devirt pass during LTO at --lto-O0.

The whole-program-devirt pass needs to run at -O0 because only it
knows about the llvm.type.checked.load intrinsic: it needs to both
lower the intrinsic itself and handle it in the summary.

Differential Revision: https://reviews.llvm.org/D33571

llvm-svn: 304019

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index 054df86b094..9fd3a9021a2 100644
--- a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
+++ b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
@@ -913,6 +913,12 @@ void PassManagerBuilder::populateLTOPassManager(legacy::PassManagerBase &PM) {
 
   if (OptLevel != 0)
     addLTOOptimizationPasses(PM);
+  else {
+    // The whole-program-devirt pass needs to run at -O0 because only it knows
+    // about the llvm.type.checked.load intrinsic: it needs to both lower the
+    // intrinsic itself and handle it in the summary.
+    PM.add(createWholeProgramDevirtPass(ExportSummary, nullptr));
+  }
 
   // Create a function that performs CFI checks for cross-DSO calls with targets
   // in the current module.