Replace llvm::isPodLike<...> by llvm::is_trivially_copyable<...>

As noted in https://bugs.llvm.org/show_bug.cgi?id=36651, the specialization for
isPodLike<std::pair<...>> did not match the expectation of
std::is_trivially_copyable which makes the memcpy optimization invalid.

This patch renames the llvm::isPodLike trait into llvm::is_trivially_copyable.
Unfortunately std::is_trivially_copyable is not portable across compiler / STL
versions. So a portable version is provided too.

Note that the following specialization were invalid:

    std::pair<T0, T1>
    llvm::Optional<T>

Tests have been added to assert that former specialization are respected by the
standard usage of llvm::is_trivially_copyable, and that when a decent version
of std::is_trivially_copyable is available, llvm::is_trivially_copyable is
compared to std::is_trivially_copyable.

As of this patch, llvm::Optional is no longer considered trivially copyable,
even if T is. This is to be fixed in a later patch, as it has impact on a
long-running bug (see r347004)

Note that GCC warns about this UB, but this got silented by https://reviews.llvm.org/D50296.

Differential Revision: https://reviews.llvm.org/D54472

llvm-svn: 351701

10 files changed, 38 insertions, 0 deletions

diff --git a/llvm/unittests/ADT/ArrayRefTest.cpp b/llvm/unittests/ADT/ArrayRefTest.cpp
index ba540688cb5..a5609f89ff9 100644
--- a/llvm/unittests/ADT/ArrayRefTest.cpp
+++ b/llvm/unittests/ADT/ArrayRefTest.cpp
@@ -248,4 +248,7 @@ TEST(ArrayRefTest, makeArrayRef) {
   EXPECT_TRUE(AR2.equals(AR2Ref));
 }
 
+static_assert(is_trivially_copyable<ArrayRef<int>>::value,
+              "trivially copyable");
+
 } // end anonymous namespace
diff --git a/llvm/unittests/ADT/ImmutableListTest.cpp b/llvm/unittests/ADT/ImmutableListTest.cpp
index bd5289d6b29..b0b1e0e6c29 100644
--- a/llvm/unittests/ADT/ImmutableListTest.cpp
+++ b/llvm/unittests/ADT/ImmutableListTest.cpp
@@ -267,4 +267,7 @@ TEST_F(ImmutableListTest, LongListOrderingTest) {
   ASSERT_EQ(6, i);
 }
 
+static_assert(is_trivially_copyable<ImmutableList<Wrapper<long>>>::value,
+              "trivially copyable");
+
 } // namespace
diff --git a/llvm/unittests/ADT/PointerIntPairTest.cpp b/llvm/unittests/ADT/PointerIntPairTest.cpp
index 95e280330a7..6b3a4c055c9 100644
--- a/llvm/unittests/ADT/PointerIntPairTest.cpp
+++ b/llvm/unittests/ADT/PointerIntPairTest.cpp
@@ -61,6 +61,9 @@ TEST(PointerIntPairTest, GetSet) {
   Pair2.setPointerAndInt(&s, E::Case3);
   EXPECT_EQ(&s, Pair2.getPointer());
   EXPECT_EQ(E::Case3, Pair2.getInt());
+
+  static_assert(is_trivially_copyable<PointerIntPair<S *, 2, E>>::value,
+                "trivially copyable");
 }
 
 TEST(PointerIntPairTest, DefaultInitialize) {
@@ -96,6 +99,11 @@ TEST(PointerIntPairTest, ManyUnusedBits) {
 
   EXPECT_EQ(FixnumPointerTraits::NumLowBitsAvailable - 1,
             PointerLikeTypeTraits<decltype(pair)>::NumLowBitsAvailable);
+
+  static_assert(
+      is_trivially_copyable<
+          PointerIntPair<Fixnum31, 1, bool, FixnumPointerTraits>>::value,
+      "trivially copyable");
 }
 
 } // end anonymous namespace
diff --git a/llvm/unittests/ADT/StringRefTest.cpp b/llvm/unittests/ADT/StringRefTest.cpp
index fbb60e6ce26..6f83dc3224a 100644
--- a/llvm/unittests/ADT/StringRefTest.cpp
+++ b/llvm/unittests/ADT/StringRefTest.cpp
@@ -1061,4 +1061,6 @@ TEST(StringRefTest, StringLiteral) {
   EXPECT_EQ(StringRef("Bar"), Strings[1]);
 }
 
+static_assert(is_trivially_copyable<StringRef>::value, "trivially copyable");
+
 } // end anonymous namespace
diff --git a/llvm/unittests/Analysis/BlockFrequencyInfoTest.cpp b/llvm/unittests/Analysis/BlockFrequencyInfoTest.cpp
index 5572f5ba597..2aeba947a74 100644
--- a/llvm/unittests/Analysis/BlockFrequencyInfoTest.cpp
+++ b/llvm/unittests/Analysis/BlockFrequencyInfoTest.cpp
@@ -7,6 +7,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Analysis/BlockFrequencyInfo.h"
+#include "llvm/Analysis/BlockFrequencyInfoImpl.h"
 #include "llvm/Analysis/BranchProbabilityInfo.h"
 #include "llvm/Analysis/LoopInfo.h"
 #include "llvm/AsmParser/Parser.h"
@@ -90,5 +91,8 @@ TEST_F(BlockFrequencyInfoTest, Basic) {
   EXPECT_EQ(BFI.getBlockFreq(BB3).getFrequency(), BB3Freq);
 }
 
+static_assert(is_trivially_copyable<bfi_detail::BlockMass>::value,
+              "trivially copyable");
+
 } // end anonymous namespace
 } // end namespace llvm
diff --git a/llvm/unittests/Bitcode/BitstreamReaderTest.cpp b/llvm/unittests/Bitcode/BitstreamReaderTest.cpp
index e9e6d9a1d07..85954858609 100644
--- a/llvm/unittests/Bitcode/BitstreamReaderTest.cpp
+++ b/llvm/unittests/Bitcode/BitstreamReaderTest.cpp
@@ -147,4 +147,7 @@ TEST(BitstreamReaderTest, shortRead) {
   }
 }
 
+static_assert(is_trivially_copyable<BitCodeAbbrevOp>::value,
+              "trivially copyable");
+
 } // end anonymous namespace
diff --git a/llvm/unittests/CodeGen/CMakeLists.txt b/llvm/unittests/CodeGen/CMakeLists.txt
index 5ef8c2afb8c..772c075de12 100644
--- a/llvm/unittests/CodeGen/CMakeLists.txt
+++ b/llvm/unittests/CodeGen/CMakeLists.txt
@@ -19,6 +19,7 @@ add_llvm_unittest(CodeGenTests
   MachineInstrTest.cpp
   MachineOperandTest.cpp
   ScalableVectorMVTsTest.cpp
+  TypeTraitsTest.cpp
   )
 
 add_subdirectory(GlobalISel)
diff --git a/llvm/unittests/CodeGen/MachineInstrTest.cpp b/llvm/unittests/CodeGen/MachineInstrTest.cpp
index 880e013b99f..2678a4589f9 100644
--- a/llvm/unittests/CodeGen/MachineInstrTest.cpp
+++ b/llvm/unittests/CodeGen/MachineInstrTest.cpp
@@ -272,4 +272,6 @@ TEST(MachineInstrPrintingTest, DebugLocPrinting) {
       StringRef(OS.str()).endswith("filename:1:5"));
 }
 
+static_assert(is_trivially_copyable<MCOperand>::value, "trivially copyable");
+
 } // end namespace
diff --git a/llvm/unittests/IR/CFGBuilder.cpp b/llvm/unittests/IR/CFGBuilder.cpp
index ca7a0555dd0..a2016f7e6cb 100644
--- a/llvm/unittests/IR/CFGBuilder.cpp
+++ b/llvm/unittests/IR/CFGBuilder.cpp
@@ -8,6 +8,7 @@
 
 #include "CFGBuilder.h"
 
+#include "llvm/IR/CFG.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/Support/Debug.h"
@@ -265,3 +266,11 @@ TEST(CFGBuilder, Rebuild) {
   EXPECT_TRUE(isa<SwitchInst>(B.getOrAddBlock("c")->getTerminator()));
   EXPECT_TRUE(isa<SwitchInst>(B.getOrAddBlock("d")->getTerminator()));
 }
+
+static_assert(is_trivially_copyable<succ_iterator>::value,
+              "trivially copyable");
+static_assert(is_trivially_copyable<succ_const_iterator>::value,
+              "trivially copyable");
+static_assert(is_trivially_copyable<succ_range>::value, "trivially copyable");
+static_assert(is_trivially_copyable<succ_const_range>::value,
+              "trivially copyable");
diff --git a/llvm/unittests/Support/ScaledNumberTest.cpp b/llvm/unittests/Support/ScaledNumberTest.cpp
index 449c0477b0a..3fa63b7bf3c 100644
--- a/llvm/unittests/Support/ScaledNumberTest.cpp
+++ b/llvm/unittests/Support/ScaledNumberTest.cpp
@@ -562,4 +562,7 @@ TEST(ScaledNumberHelpersTest, toIntBug) {
   EXPECT_EQ(1u, (n * n).toInt<uint32_t>());
 }
 
+static_assert(is_trivially_copyable<ScaledNumber<uint32_t>>::value,
+              "trivially copyable");
+
 } // end namespace