isl-codegen: Support '<' and '>'

Previously isl always generated '<=' or '>='. However, in many cases '<' or '>'
leads to simpler code. This commit updates isl and adds the relevant code
generation support to Polly.

llvm-svn: 166020
diff --git a/polly/lib/CodeGen/CodeGeneration.cpp b/polly/lib/CodeGen/CodeGeneration.cpp
index f1d1487..804ff9f 100644
--- a/polly/lib/CodeGen/CodeGeneration.cpp
+++ b/polly/lib/CodeGen/CodeGeneration.cpp
@@ -448,7 +448,8 @@
   UpperBound = ExpGen.codegen(f->UB, IntPtrTy);
   Stride = Builder.getInt(APInt_from_MPZ(f->stride));
 
-  IV = createLoop(LowerBound, UpperBound, Stride, Builder, P, AfterBB);
+  IV = createLoop(LowerBound, UpperBound, Stride, Builder, P, AfterBB,
+                  CmpInst::ICMP_SLE);
 
   // Add loop iv to symbols.
   ClastVars[f->iterator] = IV;