From db797c0e595f0e3a3add96430d4eb0cdd9b11e9b Mon Sep 17 00:00:00 2001
From: Krzysztof Parzyszek <kparzysz@codeaurora.org>
Date: Mon, 23 Oct 2017 19:35:25 +0000
Subject: [PATCH] [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
---
 lib/Target/Hexagon/HexagonISelLowering.cpp |  3 ++-
 test/CodeGen/Hexagon/call-ret-i1.ll        | 23 ++++++++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 test/CodeGen/Hexagon/call-ret-i1.ll

diff --git a/lib/Target/Hexagon/HexagonISelLowering.cpp b/lib/Target/Hexagon/HexagonISelLowering.cpp
index bece022eabf..bd5050aae30 100644
--- 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
index 00000000000..3838e8a6e88
--- /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 }
-- 
2.40.0