[X86] Make hasFP constant time

[oota-llvm.git] / lib / Target / X86 / X86ISelLowering.cpp

diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 7d80e2185f9a022a21d464b537684bcf1ca7fe7c..92360cce40a876a20f425e276703e084b6513e18 100644 (file)
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -27982,6 +27982,18 @@ bool X86TargetLowering::isTypeDesirableForOp(unsigned Opc, EVT VT) const {
   }
 }
 
+/// This function checks if any of the users of EFLAGS copies the EFLAGS. We
+/// know that the code that lowers COPY of EFLAGS has to use the stack, and if
+/// we don't adjust the stack we clobber the first frame index.
+/// See X86InstrInfo::copyPhysReg.
+bool X86TargetLowering::hasCopyImplyingStackAdjustment(
+    MachineFunction *MF) const {
+  const MachineRegisterInfo &MRI = MF->getRegInfo();
+
+  return any_of(MRI.reg_instructions(X86::EFLAGS),
+                [](const MachineInstr &RI) { return RI.isCopy(); });
+}
+
 /// IsDesirableToPromoteOp - This method query the target whether it is
 /// beneficial for dag combiner to promote the specified node. If true, it
 /// should return the desired promotion type by reference.