From 02c19658ffe935e09fc1d84b30f09beadb87fe52 Mon Sep 17 00:00:00 2001
From: Guillaume Chatelet <gchatelet@google.com>
Date: Mon, 30 Sep 2019 09:59:31 +0000
Subject: [PATCH] [Alignment][NFC] Adding a max function.

Summary:
This is patch is part of a series to introduce an Alignment type.
See this thread for context: http://lists.llvm.org/pipermail/llvm-dev/2019-July/133851.html
See this patch for the introduction of the type: https://reviews.llvm.org/D64790

Reviewers: courbet

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68201

llvm-svn: 373196
---
 llvm/include/llvm/Support/Alignment.h    |  8 ++++++++
 llvm/unittests/Support/AlignmentTest.cpp | 23 +++++++++++++++++++++++
 2 files changed, 31 insertions(+)

diff --git a/llvm/include/llvm/Support/Alignment.h b/llvm/include/llvm/Support/Alignment.h
index c90d8d72d44c..3d8a4235b0e6 100644
--- a/llvm/include/llvm/Support/Alignment.h
+++ b/llvm/include/llvm/Support/Alignment.h
@@ -333,6 +333,14 @@ inline MaybeAlign operator/(MaybeAlign Lhs, uint64_t Divisor) {
   return Lhs ? Lhs.getValue() / Divisor : MaybeAlign();
 }
 
+inline Align max(MaybeAlign Lhs, Align Rhs) {
+  return Lhs && *Lhs > Rhs ? *Lhs : Rhs;
+}
+
+inline Align max(Align Lhs, MaybeAlign Rhs) {
+  return Rhs && *Rhs > Lhs ? *Rhs : Lhs;
+}
+
 #undef ALIGN_CHECK_ISPOSITIVE
 #undef ALIGN_CHECK_ISSET
 
diff --git a/llvm/unittests/Support/AlignmentTest.cpp b/llvm/unittests/Support/AlignmentTest.cpp
index f9cc27b8f423..0b1435912b93 100644
--- a/llvm/unittests/Support/AlignmentTest.cpp
+++ b/llvm/unittests/Support/AlignmentTest.cpp
@@ -227,6 +227,29 @@ TEST(AlignmentTest, AlignComparisons) {
   }
 }
 
+TEST(AlignmentTest, Max) {
+  // We introduce std::max here to test ADL.
+  using std::max;
+
+  // Uses llvm::max.
+  EXPECT_EQ(max(MaybeAlign(), Align(2)), Align(2));
+  EXPECT_EQ(max(Align(2), MaybeAlign()), Align(2));
+
+  EXPECT_EQ(max(MaybeAlign(1), Align(2)), Align(2));
+  EXPECT_EQ(max(Align(2), MaybeAlign(1)), Align(2));
+
+  EXPECT_EQ(max(MaybeAlign(2), Align(2)), Align(2));
+  EXPECT_EQ(max(Align(2), MaybeAlign(2)), Align(2));
+
+  EXPECT_EQ(max(MaybeAlign(4), Align(2)), Align(4));
+  EXPECT_EQ(max(Align(2), MaybeAlign(4)), Align(4));
+
+  // Uses std::max.
+  EXPECT_EQ(max(Align(2), Align(4)), Align(4));
+  EXPECT_EQ(max(MaybeAlign(2), MaybeAlign(4)), MaybeAlign(4));
+  EXPECT_EQ(max(MaybeAlign(), MaybeAlign()), MaybeAlign());
+}
+
 TEST(AlignmentTest, AssumeAligned) {
   EXPECT_EQ(assumeAligned(0), Align(1));
   EXPECT_EQ(assumeAligned(0), Align());