Fix alignment on alloca's for parameters using ABIArgInfo::Expand.

llvm-svn: 143658

2 files changed, 14 insertions, 4 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 6e3b70cef85..92ac5ae560e 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -1058,10 +1058,11 @@ void CodeGenFunction::EmitFunctionProlog(const CGFunctionInfo &FI,
       // If this structure was expanded into multiple arguments then
       // we need to create a temporary and reconstruct it from the
       // arguments.
-      llvm::Value *Temp = CreateMemTemp(Ty, Arg->getName() + ".addr");
-      llvm::Function::arg_iterator End =
-        ExpandTypeFromArgs(Ty, MakeAddrLValue(Temp, Ty), AI);
-      EmitParmDecl(*Arg, Temp, ArgNo);
+      llvm::AllocaInst *Alloca = CreateMemTemp(Ty);
+      Alloca->setAlignment(getContext().getDeclAlign(Arg).getQuantity());
+      LValue LV = MakeAddrLValue(Alloca, Ty, Alloca->getAlignment());
+      llvm::Function::arg_iterator End = ExpandTypeFromArgs(Ty, LV, AI);
+      EmitParmDecl(*Arg, Alloca, ArgNo);
 
       // Name the arguments used in expansion and increment AI.
       unsigned Index = 0;
diff --git a/clang/test/CodeGen/align-param.c b/clang/test/CodeGen/align-param.c
index 15a8c2a79a3..8907f66409a 100644
--- a/clang/test/CodeGen/align-param.c
+++ b/clang/test/CodeGen/align-param.c
@@ -7,3 +7,12 @@ int test (long long x) {
 }
 // CHECK: define i32 @test
 // CHECK: alloca i64, align 8
+
+
+// Make sure we honor the aligned attribute.
+struct X { int x,y,z,a; };
+int test2(struct X x __attribute((aligned(16)))) {
+  return x.z;
+}
+// CHECK: define i32 @test2
+// CHECK: alloca %struct.X, align 16