[PATCH] Do not insert a tail call when returning multiple values on X86

[Keno Fischer]

Updated the test case based on comments.

http://reviews.llvm.org/D4968

Files:
  lib/Target/X86/X86ISelLowering.cpp
  test/CodeGen/X86/tailcall-multiret.ll

Index: lib/Target/X86/X86ISelLowering.cpp
===================================================================
--- lib/Target/X86/X86ISelLowering.cpp
+++ lib/Target/X86/X86ISelLowering.cpp
@@ -2052,6 +2052,13 @@
        UI != UE; ++UI) {
     if (UI->getOpcode() != X86ISD::RET_FLAG)
       return false;
+    // If we are returning more than one value, we can definitely
+    // not make a tail call see PR19530
+    if (UI->getNumOperands() > 4)
+      return false;
+    if (UI->getNumOperands() == 4 &&
+        UI->getOperand(UI->getNumOperands()-1).getValueType() != MVT::Glue)
+      return false;
     HasRet = true;
   }
 
Index: test/CodeGen/X86/tailcall-multiret.ll
===================================================================
--- /dev/null
+++ test/CodeGen/X86/tailcall-multiret.ll
@@ -0,0 +1,17 @@
+; RUN: llc < %s -mtriple=x86_64-linux-gnu -mcpu=core2 | FileCheck %s
+; See PR19530
+declare double    @llvm.powi.f64(double %Val, i32 %power)
+define <3 x double> @julia_foo17589(i32 %arg) {
+  %tmp1 = call double @llvm.powi.f64(double 1.000000e+00, i32 %arg)
+; CHECK: callq   __powidf2
+  %tmp2 = insertelement <3 x double> undef, double %tmp1, i32 0
+  %tmp3 = call double @llvm.powi.f64(double 2.000000e+00, i32 %arg)
+; CHECK: callq   __powidf2
+  %tmp4 = insertelement <3 x double> %tmp2, double %tmp3, i32 1
+  %tmp5 = call double @llvm.powi.f64(double 3.000000e+00, i32 %arg)
+; CHECK: callq   __powidf2
+  %tmp6 = insertelement <3 x double> %tmp4, double %tmp5, i32 2
+; CHECK-NOT: TAILCALL
+  ret <3 x double> %tmp6
+}
+
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