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

diff --git a/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp b/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp
index 054df86..9fd3a90 100644 (file)
--- 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.

diff --git a/llvm/test/LTO/Resolution/X86/type-checked-load.ll b/llvm/test/LTO/Resolution/X86/type-checked-load.ll
new file mode 100644 (file)
index 0000000..3ec783b
--- /dev/null
+++ b/llvm/test/LTO/Resolution/X86/type-checked-load.ll
@@ -0,0 +1,16 @@
+; RUN: llvm-as -o %t %s
+; RUN: llvm-lto2 run %t -O0 -r %t,foo,px -o %t2
+
+; This just tests that we don't crash when compiling this test case.
+; It means that the wholeprogramdevirt pass must have run and lowered
+; the llvm.type.checked.load call.
+
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+define {i8*, i1} @foo(i8* %ptr) {
+  %pair = call {i8*, i1} @llvm.type.checked.load(i8* %ptr, i32 16, metadata !"foo")
+  ret {i8*, i1} %pair
+}
+
+declare {i8*, i1} @llvm.type.checked.load(i8* %ptr, i32 %offset, metadata %type)