[Hexagon] Return the correct chain edge for i1 function calls

In HexagonISelLowering, there is code to handle the case when
a function returns an i1 type. In this case, we need to generate
extra nodes to copy the result from R0 to a predicate register.

The code was returning the wrong value for the chain edge which
caused an assert "Wrong topological sorting" when converting the
instructions to MIs.

This patch fixes the problem by returning the chain for the final
copy.

Patch by Brendon Cahoon.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@316367 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Target/Hexagon/HexagonISelLowering.cpp b/lib/Target/Hexagon/HexagonISelLowering.cpp
index bece022eabf7f1ea6f5e2178f540878d730670fd..bd5050aae308d46a22db84057b9acdc8c08fd79b 100644 (file)
--- a/lib/Target/Hexagon/HexagonISelLowering.cpp
+++ b/lib/Target/Hexagon/HexagonISelLowering.cpp
@@ -677,13 +677,14 @@ SDValue HexagonTargetLowering::LowerCallResult(
       // as an implicit def to the call (EmitMachineNode).
       RetVal = DAG.getCopyFromReg(TPR.getValue(0), dl, PredR, MVT::i1);
       Glue = TPR.getValue(1);
+      Chain = TPR.getValue(0);
     } else {
       RetVal = DAG.getCopyFromReg(Chain, dl, RVLocs[i].getLocReg(),
                                   RVLocs[i].getValVT(), Glue);
       Glue = RetVal.getValue(2);
+      Chain = RetVal.getValue(1);
     }
     InVals.push_back(RetVal.getValue(0));
-    Chain = RetVal.getValue(1);
   }
 
   return Chain;

diff --git a/test/CodeGen/Hexagon/call-ret-i1.ll b/test/CodeGen/Hexagon/call-ret-i1.ll
new file mode 100644 (file)
index 0000000..3838e8a
--- /dev/null
+++ b/test/CodeGen/Hexagon/call-ret-i1.ll
@@ -0,0 +1,23 @@
+; RUN: llc -march=hexagon < %s
+; REQUIRES: asserts
+
+; Test that the compiler does not assert because the DAG is not correct.
+; CHECK: call foo
+
+%returntype = type { i1, i32 }
+
+define i32 @test(i32* %a0, i32* %a1, i32* %a2) #0 {
+b3:
+  br i1 undef, label %b6, label %b4
+
+b4:                                               ; preds = %b3
+  %v5 = call %returntype @foo(i32* nonnull undef, i32* %a2, i32* %a0) #0
+  ret i32 1
+
+b6:                                               ; preds = %b3
+  unreachable
+}
+
+declare %returntype @foo(i32*, i32*, i32*) #0
+
+attributes #0 = { nounwind }