[PATCH] Fast-path for stack probes on smaller frames

[Reid Kleckner]

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Comment at: test/CodeGen/X86/win64_eh.ll:56-58
@@ +55,5 @@
+; WIN64: .seh_proc foo2_touch
+; WIN64: subq    $4096, %rsp
+; WIN64: orq     $0, (%rsp)
+; WIN64: .seh_stackalloc 4096
+; WIN64: .seh_endprologue
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I suspect the .seh_stackalloc directive needs to follow the stack adjustment if we want to support asynchronous unwinding. One could probably test this in windbg by breaking on the OR instruction and trying to get a stack trace.

http://reviews.llvm.org/D5018