1 files changed, 46 insertions, 0 deletions
diff --git a/test/CodeGen/X86/win_chkstk.ll b/test/CodeGen/X86/win_chkstk.ll
new file mode 100644
index 0000000..a377a7d
--- /dev/null
+++ b/test/CodeGen/X86/win_chkstk.ll
@@ -0,0 +1,46 @@
+; RUN: llc < %s -mtriple=i686-pc-win32 | FileCheck %s -check-prefix=WIN_X32
+; RUN: llc < %s -mtriple=x86_64-pc-win32 | FileCheck %s -check-prefix=WIN_X64
+; RUN: llc < %s -mtriple=i686-pc-mingw32 | FileCheck %s -check-prefix=MINGW_X32
+; RUN: llc < %s -mtriple=x86_64-pc-mingw32 | FileCheck %s -check-prefix=MINGW_X64
+; RUN: llc < %s -mtriple=i386-pc-linux | FileCheck %s -check-prefix=LINUX
+
+; Windows and mingw require a prologue helper routine if more than 4096 bytes area
+; allocated on the stack.  Windows uses __chkstk and mingw uses __alloca.  __alloca
+; and the 32-bit version of __chkstk will probe the stack and adjust the stack pointer.
+; The 64-bit version of __chkstk is only responsible for probing the stack.  The 64-bit
+; prologue is responsible for adjusting the stack pointer.
+
+; Stack allocation >= 4096 bytes will require call to __chkstk in the Windows ABI.
+define i32 @main4k() nounwind {
+entry:
+; WIN_X32:    calll __chkstk
+; WIN_X64:    callq __chkstk
+; MINGW_X32:  calll __alloca
+; MINGW_X64:  callq _alloca
+; LINUX-NOT:  call __chkstk
+  %array4096 = alloca [4096 x i8], align 16       ; <[4096 x i8]*> [#uses=0]
+  ret i32 0
+}
+
+; Make sure we don't call __chkstk or __alloca when we have less than a 4096 stack
+; allocation.
+define i32 @main128() nounwind {
+entry:
+; WIN_X32:       # BB#0:
+; WIN_X32-NOT:   calll __chkstk
+; WIN_X32:       ret
+
+; WIN_X64:       # BB#0:
+; WIN_X64-NOT:   callq __chkstk
+; WIN_X64:       ret
+
+; MINGW_X64:     # BB#0:
+; MINGW_X64-NOT: callq _alloca
+; MINGW_X64:     ret
+
+; LINUX:         # BB#0:
+; LINUX-NOT:     call __chkstk
+; LINUX:         ret
+  %array128 = alloca [128 x i8], align 16         ; <[128 x i8]*> [#uses=0]
+  ret i32 0
+}