Add WIN_FTOL_* psudo-instructions to model the unique calling convention

used by the Win32 _ftol2 runtime function. Patch by Joe Groff!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151382 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 17 insertions, 1 deletions

diff --git a/lib/Target/X86/X86InstrCompiler.td b/lib/Target/X86/X86InstrCompiler.td
index ce0a885083..ac49232912 100644
--- a/lib/Target/X86/X86InstrCompiler.td
+++ b/lib/Target/X86/X86InstrCompiler.td
@@ -125,10 +125,26 @@ def SEG_ALLOCA_64 : I<0, Pseudo, (outs GR64:$dst), (ins GR64:$size),
                       [(set GR64:$dst,
                          (X86SegAlloca GR64:$size))]>,
                     Requires<[In64BitMode]>;
-
 }
 
+// The MSVC runtime contains an _ftol2 routine for converting floating-point
+// to integer values. It has a strange calling convention: the input is
+// popped from the x87 stack, and the return value is given in EDX:EAX. No
+// other registers (aside from flags) are touched.
+// Microsoft toolchains do not support 80-bit precision, so a WIN_FTOL_80
+// variant is unnecessary.
+
+let Defs = [EAX, EDX, EFLAGS], FPForm = SpecialFP in {
+  def WIN_FTOL_32 : I<0, Pseudo, (outs), (ins RFP32:$src),
+                      "# win32 fptoui",
+                      [(X86WinFTOL RFP32:$src)]>,
+                    Requires<[In32BitMode]>;
 
+  def WIN_FTOL_64 : I<0, Pseudo, (outs), (ins RFP64:$src),
+                      "# win32 fptoui",
+                      [(X86WinFTOL RFP64:$src)]>,
+                    Requires<[In32BitMode]>;
+}
 
 //===----------------------------------------------------------------------===//
 // EH Pseudo Instructions