[PATCH] Add a "split-stack" function attribute.

[Luqman Aden]

================
Comment at: lib/Target/X86/X86ISelLowering.cpp:10743
@@ +10742,3 @@
+  if (!Lower) {
+    const TargetLowering &TLI = DAG.getTargetLoweringInfo();
+    SDNode* Node = Op.getNode();
----------------
Rafael Ávila de Espíndola wrote:
> Can't you call ExpandDYNAMIC_STACKALLOC?
Is that possible? I wasn't sure of how to and asking in #llvm didn't yield any answers.

================
Comment at: include/llvm/CodeGen/CommandFlags.h:194
@@ -193,3 +193,3 @@
 
-cl::opt<bool>
+cl::opt<llvm::SplitStacks::SplitStacksMode>
 SegmentedStacks("segmented-stacks",
----------------
Rafael Ávila de Espíndola wrote:
> Why do you need this option? The point of having a positive attribute (split-stack)  attribute is that we can remove the existing codegen option.
I guess you don't but I didn't want to break any existing stuff relying on setting it globally. I did change the default mode to be the per-fn attribute.


http://llvm-reviews.chandlerc.com/D1905