Teach CodeGenPrep to look past bitcast when it's duplicating return instruction
into predecessor blocks to enable tail call optimization.
rdar://11958338
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160894 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/CodeGen/X86/tailcall-cgp-dup.ll b/test/CodeGen/X86/tailcall-cgp-dup.ll
new file mode 100644
index 0000000..a80b90f
--- /dev/null
+++ b/test/CodeGen/X86/tailcall-cgp-dup.ll
@@ -0,0 +1,87 @@
+; RUN: llc < %s -mtriple=x86_64-apple-darwin | FileCheck %s
+
+; Teach CGP to dup returns to enable tail call optimization.
+; rdar://9147433
+
+define i32 @foo(i32 %x) nounwind ssp {
+; CHECK: foo:
+entry:
+ switch i32 %x, label %return [
+ i32 1, label %sw.bb
+ i32 2, label %sw.bb1
+ i32 3, label %sw.bb3
+ i32 4, label %sw.bb5
+ i32 5, label %sw.bb7
+ i32 6, label %sw.bb9
+ ]
+
+sw.bb: ; preds = %entry
+; CHECK: jmp _f1
+ %call = tail call i32 @f1() nounwind
+ br label %return
+
+sw.bb1: ; preds = %entry
+; CHECK: jmp _f2
+ %call2 = tail call i32 @f2() nounwind
+ br label %return
+
+sw.bb3: ; preds = %entry
+; CHECK: jmp _f3
+ %call4 = tail call i32 @f3() nounwind
+ br label %return
+
+sw.bb5: ; preds = %entry
+; CHECK: jmp _f4
+ %call6 = tail call i32 @f4() nounwind
+ br label %return
+
+sw.bb7: ; preds = %entry
+; CHECK: jmp _f5
+ %call8 = tail call i32 @f5() nounwind
+ br label %return
+
+sw.bb9: ; preds = %entry
+; CHECK: jmp _f6
+ %call10 = tail call i32 @f6() nounwind
+ br label %return
+
+return: ; preds = %entry, %sw.bb9, %sw.bb7, %sw.bb5, %sw.bb3, %sw.bb1, %sw.bb
+ %retval.0 = phi i32 [ %call10, %sw.bb9 ], [ %call8, %sw.bb7 ], [ %call6, %sw.bb5 ], [ %call4, %sw.bb3 ], [ %call2, %sw.bb1 ], [ %call, %sw.bb ], [ 0, %entry ]
+ ret i32 %retval.0
+}
+
+declare i32 @f1()
+
+declare i32 @f2()
+
+declare i32 @f3()
+
+declare i32 @f4()
+
+declare i32 @f5()
+
+declare i32 @f6()
+
+; rdar://11958338
+%0 = type opaque
+
+declare i8* @bar(i8*) uwtable optsize noinline ssp
+
+define hidden %0* @thingWithValue(i8* %self) uwtable ssp {
+entry:
+; CHECK: thingWithValue:
+; CHECK: jmp _bar
+ br i1 undef, label %if.then.i, label %if.else.i
+
+if.then.i: ; preds = %entry
+ br label %someThingWithValue.exit
+
+if.else.i: ; preds = %entry
+ %call4.i = tail call i8* @bar(i8* undef) optsize
+ br label %someThingWithValue.exit
+
+someThingWithValue.exit: ; preds = %if.else.i, %if.then.i
+ %retval.0.in.i = phi i8* [ undef, %if.then.i ], [ %call4.i, %if.else.i ]
+ %retval.0.i = bitcast i8* %retval.0.in.i to %0*
+ ret %0* %retval.0.i
+}