LegalizeDAG: Respect the result of TLI.getBooleanContents() when expanding SETCC

llvm-svn: 176695

2 files changed, 39 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index f085e444b65..743a9da0590 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -3632,8 +3632,20 @@ void SelectionDAGLegalize::ExpandNode(SDNode *Node) {
     // Otherwise, SETCC for the given comparison type must be completely
     // illegal; expand it into a SELECT_CC.
     EVT VT = Node->getValueType(0);
+    int TrueValue;
+    switch(TLI.getBooleanContents(VT.isVector())) {
+    default: assert(!"Unhandled BooleanContent value");
+    case TargetLowering::ZeroOrOneBooleanContent:
+    case TargetLowering::UndefinedBooleanContent:
+      TrueValue = 1;
+      break;
+    case TargetLowering::ZeroOrNegativeOneBooleanContent:
+      TrueValue = -1;
+      break;
+    }
     Tmp1 = DAG.getNode(ISD::SELECT_CC, dl, VT, Tmp1, Tmp2,
-                       DAG.getConstant(1, VT), DAG.getConstant(0, VT), Tmp3);
+                       DAG.getConstant(TrueValue, VT), DAG.getConstant(0, VT),
+                       Tmp3);
     Results.push_back(Tmp1);
     break;
   }
diff --git a/llvm/test/CodeGen/R600/legalizedag-bug-expand-setcc.ll b/llvm/test/CodeGen/R600/legalizedag-bug-expand-setcc.ll
new file mode 100644
index 00000000000..1aae7f9f91f
--- /dev/null
+++ b/llvm/test/CodeGen/R600/legalizedag-bug-expand-setcc.ll
@@ -0,0 +1,26 @@
+; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s
+
+; This tests a bug where LegalizeDAG was not checking the target's
+; BooleanContents value and always using one for true, when expanding
+; setcc to select_cc.
+;
+; This bug caused the icmp IR instruction to be expanded to two machine
+; instructions, when only one is needed.
+;
+
+; CHECK: @setcc_expand
+; CHECK: SET
+; CHECK-NOT: CND
+define void @setcc_expand(i32 addrspace(1)* %out, i32 %in) {
+entry:
+  %0 = icmp eq i32 %in, 5
+  br i1 %0, label %IF, label %ENDIF
+IF:
+  %1 = getelementptr i32 addrspace(1)* %out, i32 1
+  store i32 0, i32 addrspace(1)* %1
+  br label %ENDIF
+
+ENDIF:
+  store i32 0, i32 addrspace(1)* %out
+  ret void
+}