Don't import variadic functions

Summary:
This patch adds IsVariadicFunction bit to summary in order
to not import variadic functions. Inliner doesn't inline
variadic functions because it is hard to reason about it.

This one small fix improves Importer by about 16%
(going from 86% to 100% of imported functions that are
inlined anywhere)
on some spec benchmarks like 'int' and others.

Reviewers: eraman, mehdi_amini, tejohnson

Subscribers: mehdi_amini, llvm-commits

Differential Revision: https://reviews.llvm.org/D23339

llvm-svn: 278432

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
index 73a30c61eca..2c3292527f5 100644
--- a/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/llvm/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -720,7 +720,7 @@ static GlobalValue::LinkageTypes getDecodedLinkage(unsigned Val) {
   }
 }
 
-// Decode the flags for GlobalValue in the summary
+/// Decode the flags for GlobalValue in the summary.
 static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
                                                             uint64_t Version) {
   // Summary were not emitted before LLVM 3.9, we don't need to upgrade Linkage
@@ -728,8 +728,9 @@ static GlobalValueSummary::GVFlags getDecodedGVSummaryFlags(uint64_t RawFlags,
   // to getDecodedLinkage() will need to be taken into account here as above.
   auto Linkage = GlobalValue::LinkageTypes(RawFlags & 0xF); // 4 bits
   RawFlags = RawFlags >> 4;
-  auto HasSection = RawFlags & 0x1; // bool
-  return GlobalValueSummary::GVFlags(Linkage, HasSection);
+  bool HasSection = RawFlags & 0x1;
+  bool IsNotViableToInline = RawFlags & 0x2;
+  return GlobalValueSummary::GVFlags(Linkage, HasSection, IsNotViableToInline);
 }
 
 static GlobalValue::VisibilityTypes getDecodedVisibility(unsigned Val) {