[mips] Reland r310704

Recommit this change which was previously reverted
for the 5.0.0 release since the failures identified
were dealt with in r325782.

llvm-svn: 325872

1 files changed, 8 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index 4ca421bb863..7d597437683 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -6870,6 +6870,14 @@ MipsABIInfo::classifyArgumentType(QualType Ty, uint64_t &Offset) const {
       return getNaturalAlignIndirect(Ty, RAA == CGCXXABI::RAA_DirectInMemory);
     }
 
+    // Use indirect if the aggregate cannot fit into registers for
+    // passing arguments according to the ABI
+    unsigned Threshold = IsO32 ? 16 : 64;
+
+    if(getContext().getTypeSizeInChars(Ty) > CharUnits::fromQuantity(Threshold))
+      return ABIArgInfo::getIndirect(CharUnits::fromQuantity(Align), true,
+                                     getContext().getTypeAlign(Ty) / 8 > Align);
+
     // If we have reached here, aggregates are passed directly by coercing to
     // another structure type. Padding is inserted if the offset of the
     // aggregate is unaligned.