Revert "Re-enable byval for ARM in clang. rdar://problem/7662569"

This reverts commit 67d097e1232b7d66f58989c16a45b8a11721f76e.
We found a miscompile with ARM byval, which is still being investigated.
In the meantime, this works around the problem by disabling ARM byval.

Conflicts:
	lib/CodeGen/TargetInfo.cpp

llvm-svn: 136662

1 files changed, 6 insertions, 10 deletions

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 167a0b12b88..9dbd11cb487 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -2400,21 +2400,17 @@ ABIArgInfo ARMABIInfo::classifyArgumentType(QualType Ty) const {
 
   // Otherwise, pass by coercing to a structure of the appropriate size.
   //
+  // FIXME: This is kind of nasty... but there isn't much choice because the ARM
+  // backend doesn't support byval.
   // FIXME: This doesn't handle alignment > 64 bits.
   llvm::Type* ElemTy;
   unsigned SizeRegs;
-  if (getContext().getTypeSizeInChars(Ty) <= CharUnits::fromQuantity(64)) {
-    ElemTy = llvm::Type::getInt32Ty(getVMContext());
-    SizeRegs = (getContext().getTypeSize(Ty) + 31) / 32;
-  } else if (getABIKind() == ARMABIInfo::APCS) {
-    // Initial ARM ByVal support is APCS-only.
-    return ABIArgInfo::getIndirect(0, /*ByVal=*/true);
-  } else {
-    // FIXME: This is kind of nasty... but there isn't much choice
-    // because most of the ARM calling conventions don't yet support
-    // byval.
+  if (getContext().getTypeAlign(Ty) > 32) {
     ElemTy = llvm::Type::getInt64Ty(getVMContext());
     SizeRegs = (getContext().getTypeSize(Ty) + 63) / 64;
+  } else {
+    ElemTy = llvm::Type::getInt32Ty(getVMContext());
+    SizeRegs = (getContext().getTypeSize(Ty) + 31) / 32;
   }
 
   llvm::Type *STy =