[TargetSchedule] Minor refactor in computeInstrLatency. NFC

The intent of revision r300311 was to add a check for invalid scheduling class
descriptors. However, it ended up adding a redundant call in a basic block that
should not be reachable.

llvm-svn: 327231

1 files changed, 4 insertions, 6 deletions

diff --git a/llvm/lib/CodeGen/TargetSchedule.cpp b/llvm/lib/CodeGen/TargetSchedule.cpp
index 86dbf1b2aea..7d636b126e0 100644
--- a/llvm/lib/CodeGen/TargetSchedule.cpp
+++ b/llvm/lib/CodeGen/TargetSchedule.cpp
@@ -274,14 +274,12 @@ unsigned TargetSchedModel::computeInstrLatency(unsigned Opcode) const {
   unsigned SCIdx = TII->get(Opcode).getSchedClass();
   const MCSchedClassDesc *SCDesc = SchedModel.getSchedClassDesc(SCIdx);
 
-  if (SCDesc->isValid() && !SCDesc->isVariant())
+  if (!SCDesc->isValid())
+    return 0;
+  if (!SCDesc->isVariant())
     return computeInstrLatency(*SCDesc);
 
-  if (SCDesc->isValid()) {
-    assert (!SCDesc->isVariant() && "No MI sched latency: SCDesc->isVariant()");
-    return computeInstrLatency(*SCDesc);
-  }
-  return 0;
+  llvm_unreachable("No MI sched latency");
 }
 
 unsigned