An stdcall function calling a non-stdcall function

cannot use tailcall.  PR 8461.

llvm-svn: 117322

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -2532,6 +2532,11 @@ X86TargetLowering::IsEligibleForTailCallOptimization(SDValue Callee,
     }
   }
 
+  // An stdcall caller is expected to clean up its arguments; the callee
+  // isn't going to do that.   PR 8461.
+  if (!CCMatch && CallerCC==CallingConv::X86_StdCall)
+    return false;
+
   return true;
 }
 

llvm/test/CodeGen/X86/stdcall-notailcall.ll

@@ -0,0 +1,13 @@
+; RUN: llc -mtriple=i386-apple-darwin11 -O2 < %s | FileCheck %s
+
+%struct.I = type { i32 (...)** }
+define x86_stdcallcc void @bar(%struct.I* nocapture %this) ssp align 2 {
+; CHECK: bar:
+; CHECK-NOT: jmp
+; CHECK: ret $4
+entry:
+  tail call void @foo()
+  ret void
+}
+
+declare void @foo()