Minor bug in SCCP found by inspection. (I don't think it's possible to hit this...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137755 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/SCCP.cpp b/lib/Transforms/Scalar/SCCP.cpp
index 59d96be..accfbee 100644 (file)
--- a/lib/Transforms/Scalar/SCCP.cpp
+++ b/lib/Transforms/Scalar/SCCP.cpp
@@ -582,6 +582,10 @@ void SCCPSolver::getFeasibleSuccessors(TerminatorInst &TI,
   }
   
   if (SwitchInst *SI = dyn_cast<SwitchInst>(&TI)) {
+    if (TI.getNumSuccessors() < 2) {
+      Succs[0] = true;
+      return;
+    }
     LatticeVal SCValue = getValueState(SI->getCondition());
     ConstantInt *CI = SCValue.getConstantInt();
     
@@ -642,6 +646,9 @@ bool SCCPSolver::isEdgeFeasible(BasicBlock *From, BasicBlock *To) {
     return true;
   
   if (SwitchInst *SI = dyn_cast<SwitchInst>(TI)) {
+    if (SI->getNumSuccessors() < 2)
+      return true;
+
     LatticeVal SCValue = getValueState(SI->getCondition());
     ConstantInt *CI = SCValue.getConstantInt();
     

diff --git a/test/Transforms/SCCP/switch.ll b/test/Transforms/SCCP/switch.ll
new file mode 100644 (file)
index 0000000..9f93423
--- /dev/null
+++ b/test/Transforms/SCCP/switch.ll
@@ -0,0 +1,13 @@
+; RUN: opt -S -sccp < %s | FileCheck %s
+
+; Make sure we always consider the default edge executable for a switch
+; with no cases.
+declare void @foo()
+define void @test1() {
+; CHECK: define void @test1
+; CHECK: call void @foo()
+  switch i32 undef, label %d []
+d:
+  call void @foo()
+  ret void
+}