Move folding of icmp with zero after checking for min/max idioms.

Summary:
The following transformation for cmp instruction:

  icmp smin(x, PositiveValue), 0 -> icmp x, 0

should only be done after checking for min/max to prevent infinite
looping caused by a reverse canonicalization. That is why this
transformation was moved to place after the mentioned check.

Reviewers: spatel, efriedma

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D38934

Patch by: Artur Gainullin <artur.gainullin@intel.com>

llvm-svn: 315895
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
index 88ce4de..10385b0 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
+++ b/llvm/lib/Transforms/InstCombine/InstCombineInternal.h
@@ -700,6 +700,7 @@
   Instruction *foldICmpInstWithConstantNotInt(ICmpInst &Cmp);
   Instruction *foldICmpBinOp(ICmpInst &Cmp);
   Instruction *foldICmpEquality(ICmpInst &Cmp);
+  Instruction *foldICmpWithZero(ICmpInst &Cmp);
 
   Instruction *foldICmpSelectConstant(ICmpInst &Cmp, SelectInst *Select,
                                       ConstantInt *C);