Allow more tailcall optimization: calls with inputs that are all passed in registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94873 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 5dbe0bb..c0ebade 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -2258,9 +2258,18 @@
return true;
// Look for obvious safe cases to perform tail call optimization.
- // For now, only consider callees which take no arguments.
- if (!Outs.empty())
- return false;
+ // If the callee takes no arguments then go on to check the results of the
+ // call.
+ if (!Outs.empty()) {
+ // Check if stack adjustment is needed. For now, do not do this if any
+ // argument is passed on the stack.
+ SmallVector<CCValAssign, 16> ArgLocs;
+ CCState CCInfo(CalleeCC, isVarArg, getTargetMachine(),
+ ArgLocs, *DAG.getContext());
+ CCInfo.AnalyzeCallOperands(Outs, CCAssignFnForNode(CalleeCC));
+ if (CCInfo.getNextStackOffset())
+ return false;
+ }
// If the caller does not return a value, then this is obviously safe.
// This is one case where it's safe to perform this optimization even