diff options
| -rw-r--r-- | lib/Target/X86/X86ISelLowering.cpp | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index c6bdc2e356..747a15b947 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -3406,8 +3406,17 @@ SDOperand X86TargetLowering::LowerCALL(SDOperand Op, SelectionDAG &DAG) { } } + +// Lower dynamic stack allocation to _alloca call for Cygwin/Mingw targets. +// Calls to _alloca is needed to probe the stack when allocating more than 4k +// bytes in one go. Touching the stack at 4K increments is necessary to ensure +// that the guard pages used by the OS virtual memory manager are allocated in +// correct sequence. SDOperand X86TargetLowering::LowerDYNAMIC_STACKALLOC(SDOperand Op, SelectionDAG &DAG) { + assert(Subtarget->isTargetCygMing() && + "This should be used only on Cygwin/Mingw targets"); + // Get the inputs. SDOperand Chain = Op.getOperand(0); SDOperand Size = Op.getOperand(1); |