SimplifyCFG: GEPs with constant indices are cheap enough to be executed unconditionally.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126445 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index fb660db..c670885 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -247,6 +247,11 @@
     if (PBB->getFirstNonPHIOrDbg() != I)
       return false;
     break;
+  case Instruction::GetElementPtr:
+    // GEPs are cheap if all indices are constant.
+    if (!cast<GetElementPtrInst>(I)->hasAllConstantIndices())
+      return false;
+    break;
   case Instruction::Add:
   case Instruction::Sub:
   case Instruction::And: