- If a dynamic_stackalloc alignment requirement is <= stack alignment, then the alignment argument is ignored.
- *Always* round up the size of the allocation to multiples of stack
alignment to ensure the stack ptr is never left in an invalid state after a dynamic_stackalloc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41132 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index 90ed454..a99640a 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -2329,21 +2329,21 @@
AllocSize = DAG.getNode(ISD::MUL, IntPtr, AllocSize,
getIntPtrConstant(TySize));
- // Handle alignment. If the requested alignment is less than the stack
- // alignment, ignore it and round the size of the allocation up to the stack
- // alignment size. If the size is greater than or equal to the stack
- // alignment, we note this in the DYNAMIC_STACKALLOC node.
+ // Handle alignment. If the requested alignment is less than or equal to
+ // the stack alignment, ignore it. If the size is greater than or equal to
+ // the stack alignment, we note this in the DYNAMIC_STACKALLOC node.
unsigned StackAlign =
TLI.getTargetMachine().getFrameInfo()->getStackAlignment();
- if (Align < StackAlign) {
+ if (Align <= StackAlign)
Align = 0;
- // Add SA-1 to the size.
- AllocSize = DAG.getNode(ISD::ADD, AllocSize.getValueType(), AllocSize,
- getIntPtrConstant(StackAlign-1));
- // Mask out the low bits for alignment purposes.
- AllocSize = DAG.getNode(ISD::AND, AllocSize.getValueType(), AllocSize,
- getIntPtrConstant(~(uint64_t)(StackAlign-1)));
- }
+
+ // Round the size of the allocation up to the stack alignment size
+ // by add SA-1 to the size.
+ AllocSize = DAG.getNode(ISD::ADD, AllocSize.getValueType(), AllocSize,
+ getIntPtrConstant(StackAlign-1));
+ // Mask out the low bits for alignment purposes.
+ AllocSize = DAG.getNode(ISD::AND, AllocSize.getValueType(), AllocSize,
+ getIntPtrConstant(~(uint64_t)(StackAlign-1)));
SDOperand Ops[] = { getRoot(), AllocSize, getIntPtrConstant(Align) };
const MVT::ValueType *VTs = DAG.getNodeValueTypes(AllocSize.getValueType(),