Move all of the header files which are involved in modelling the LLVM IR

[oota-llvm.git] / lib / Transforms / InstCombine / InstCombineAndOrXor.cpp

diff --git a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
index ecae3b60452e3dc4c64eb93d412c87016bab88ad..c1e60d4c427b3c50e9a23a1607cf0406c1422f17 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
+++ b/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp
@@ -13,7 +13,7 @@
 
 #include "InstCombine.h"
 #include "llvm/Analysis/InstructionSimplify.h"
-#include "llvm/Intrinsics.h"
+#include "llvm/IR/Intrinsics.h"
 #include "llvm/Support/ConstantRange.h"
 #include "llvm/Support/PatternMatch.h"
 #include "llvm/Transforms/Utils/CmpInstAnalysis.h"
@@ -1524,6 +1524,20 @@ Value *InstCombiner::FoldOrOfICmps(ICmpInst *LHS, ICmpInst *RHS) {
         AddCST = ConstantExpr::getSub(AddOne(RHSCst), LHSCst);
         return Builder->CreateICmpULT(Add, AddCST);
       }
+
+      if (LHS->getOperand(0) == RHS->getOperand(0)) {
+        // if LHSCst and RHSCst differ only by one bit:
+        // (A == C1 || A == C2) -> (A & ~(C1 ^ C2)) == C1
+        assert(LHSCst->getValue().ule(LHSCst->getValue()));
+
+        APInt Xor = LHSCst->getValue() ^ RHSCst->getValue();
+        if (Xor.isPowerOf2()) {
+          Value *NegCst = Builder->getInt(~Xor);
+          Value *And = Builder->CreateAnd(LHS->getOperand(0), NegCst);
+          return Builder->CreateICmp(ICmpInst::ICMP_EQ, And, LHSCst);
+        }
+      }
+
       break;                         // (X == 13 | X == 15) -> no change
     case ICmpInst::ICMP_UGT:         // (X == 13 | X u> 14) -> no change
     case ICmpInst::ICMP_SGT:         // (X == 13 | X s> 14) -> no change