If ADD, SUB, or MUL have an overflow bit that's used, don't do transformation on

them. The DAG combiner expects that nodes that are transformed have one value
result.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60857 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 51 insertions, 4 deletions

diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 9cc8061f18..7e78923f6d 100644
--- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -966,6 +966,11 @@ SDValue DAGCombiner::visitADD(SDNode *N) {
     SDValue FoldedVOp = SimplifyVBinOp(N);
     if (FoldedVOp.getNode()) return FoldedVOp;
   }
+
+  if (N->getNumValues() != 1)
+    // FIXME: DAG combiner cannot handle multiple return values on arithmetic
+    //        operators.
+    return SDValue();
   
   // fold (add x, undef) -> undef
   if (N0.getOpcode() == ISD::UNDEF)
@@ -1161,6 +1166,11 @@ SDValue DAGCombiner::visitSUB(SDNode *N) {
     SDValue FoldedVOp = SimplifyVBinOp(N);
     if (FoldedVOp.getNode()) return FoldedVOp;
   }
+
+  if (N->getNumValues() != 1)
+    // FIXME: DAG combiner cannot handle multiple return values on arithmetic
+    //        operators.
+    return SDValue();
   
   // fold (sub x, x) -> 0
   if (N0 == N1)
@@ -1220,6 +1230,11 @@ SDValue DAGCombiner::visitMUL(SDNode *N) {
     if (FoldedVOp.getNode()) return FoldedVOp;
   }
   
+  if (N->getNumValues() != 1)
+    // FIXME: DAG combiner cannot handle multiple return values on arithmetic
+    //        operators.
+    return SDValue();
+    
   // fold (mul x, undef) -> 0
   if (N0.getOpcode() == ISD::UNDEF || N1.getOpcode() == ISD::UNDEF)
     return DAG.getConstant(0, VT);
diff --git a/test/CodeGen/X86/add-with-overflow.ll b/test/CodeGen/X86/add-with-overflow.ll
index baf577168c..4b9aa98c84 100644
--- a/test/CodeGen/X86/add-with-overflow.ll
+++ b/test/CodeGen/X86/add-with-overflow.ll
@@ -1,7 +1,7 @@
-; RUN: llvm-as < %s | llc -march=x86 | grep {jo} | count 1
-; RUN: llvm-as < %s | llc -march=x86 | grep {jc} | count 1
-; RUN: llvm-as < %s | llc -march=x86 -fast | grep {jo} | count 1
-; RUN: llvm-as < %s | llc -march=x86 -fast | grep {jc} | count 1
+; RUN: llvm-as < %s | llc -march=x86 | grep {jo} | count 2
+; RUN: llvm-as < %s | llc -march=x86 | grep {jc} | count 2
+; RUN: llvm-as < %s | llc -march=x86 -fast | grep {jo} | count 2
+; RUN: llvm-as < %s | llc -march=x86 -fast | grep {jc} | count 2
 
 @ok = internal constant [4 x i8] c"%d\0A\00"
 @no = internal constant [4 x i8] c"no\0A\00"
@@ -38,6 +38,38 @@ carry:
   ret i1 false
 }
 
+define i1 @func3() nounwind {
+entry:
+  %t = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 0, i32 0)
+  %sum = extractvalue {i32, i1} %t, 0
+  %obit = extractvalue {i32, i1} %t, 1
+  br i1 %obit, label %carry, label %normal
+
+normal:
+  %t1 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @ok, i32 0, i32 0), i32 %sum ) nounwind
+  ret i1 true
+
+carry:
+  %t2 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @no, i32 0, i32 0) ) nounwind
+  ret i1 false
+}
+
+define i1 @func4() nounwind {
+entry:
+  %t = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 0, i32 0)
+  %sum = extractvalue {i32, i1} %t, 0
+  %obit = extractvalue {i32, i1} %t, 1
+  br i1 %obit, label %carry, label %normal
+
+normal:
+  %t1 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @ok, i32 0, i32 0), i32 %sum ) nounwind
+  ret i1 true
+
+carry:
+  %t2 = tail call i32 (i8*, ...)* @printf( i8* getelementptr ([4 x i8]* @no, i32 0, i32 0) ) nounwind
+  ret i1 false
+}
+
 declare i32 @printf(i8*, ...) nounwind
 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32, i32)
 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32, i32)