Correctly align large arrays in x86-64. This fixes PR5599.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@105500 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 13 insertions, 0 deletions

diff --git a/lib/AST/ASTContext.cpp b/lib/AST/ASTContext.cpp
index 43bf21313f..6e7bb0773c 100644
--- a/lib/AST/ASTContext.cpp
+++ b/lib/AST/ASTContext.cpp
@@ -414,6 +414,15 @@ CharUnits ASTContext::getDeclAlign(const Decl *D, bool RefAsPointee) {
         T = getPointerType(RT->getPointeeType());
     }
     if (!T->isIncompleteType() && !T->isFunctionType()) {
+      unsigned MinWidth = Target.getLargeArrayMinWidth();
+      unsigned ArrayAlign = Target.getLargeArrayAlign();
+      if (isa<VariableArrayType>(T) && MinWidth != 0)
+        Align = std::max(Align, ArrayAlign);
+      if (ConstantArrayType *CT = dyn_cast<ConstantArrayType>(T)) {
+        unsigned Size = getTypeSize(CT);
+        if (MinWidth != 0 && MinWidth <= Size)
+          Align = std::max(Align, ArrayAlign);
+      }
       // Incomplete or function types default to 1.
       while (isa<VariableArrayType>(T) || isa<IncompleteArrayType>(T))
         T = cast<ArrayType>(T)->getElementType();
diff --git a/lib/Basic/TargetInfo.cpp b/lib/Basic/TargetInfo.cpp
index 6692e641f2..98249c029b 100644
--- a/lib/Basic/TargetInfo.cpp
+++ b/lib/Basic/TargetInfo.cpp
@@ -34,6 +34,8 @@ TargetInfo::TargetInfo(const std::string &T) : Triple(T) {
   DoubleAlign = 64;
   LongDoubleWidth = 64;
   LongDoubleAlign = 64;
+  LargeArrayMinWidth = 0;
+  LargeArrayAlign = 0;
   SizeType = UnsignedLong;
   PtrDiffType = SignedLong;
   IntMaxType = SignedLongLong;
diff --git a/lib/Basic/Targets.cpp b/lib/Basic/Targets.cpp
index 255c71d9b7..82c6507190 100644
--- a/lib/Basic/Targets.cpp
+++ b/lib/Basic/Targets.cpp
@@ -1278,6 +1278,8 @@ public:
     LongWidth = LongAlign = PointerWidth = PointerAlign = 64;
     LongDoubleWidth = 128;
     LongDoubleAlign = 128;
+    LargeArrayMinWidth = 128;
+    LargeArrayAlign = 128;
     IntMaxType = SignedLong;
     UIntMaxType = UnsignedLong;
     Int64Type = SignedLong;