DataFlowSanitizer: Instrumentation for memset.

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

diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index e9f3458be983f876c56b8d76ab8fe77c7762cd15..c0225ae096a4ae51cc637c885fb55f79cb4af171 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1126,6 +1126,18 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
                               Builder->getInt(RHSV ^ NotSignBit));
         }
       }
+
+      // (icmp ugt (xor X, C), ~C) -> (icmp ult X, C)
+      //   iff -C is a power of 2
+      if (ICI.getPredicate() == ICmpInst::ICMP_UGT &&
+          XorCST->getValue() == ~RHSV && (RHSV + 1).isPowerOf2())
+        return new ICmpInst(ICmpInst::ICMP_ULT, LHSI->getOperand(0), XorCST);
+
+      // (icmp ult (xor X, C), -C) -> (icmp uge X, C)
+      //   iff -C is a power of 2
+      if (ICI.getPredicate() == ICmpInst::ICMP_ULT &&
+          XorCST->getValue() == -RHSV && RHSV.isPowerOf2())
+        return new ICmpInst(ICmpInst::ICMP_UGE, LHSI->getOperand(0), XorCST);
     }
     break;
   case Instruction::And:         // (icmp pred (and X, AndCST), RHS)
@@ -1535,7 +1547,7 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
                           Builder->CreateOr(LHSI->getOperand(1), RHSV - 1),
                           LHSC);
 
-    // C1-X >u C2 -> (X|C2) == C1
+    // C1-X >u C2 -> (X|C2) != C1
     //   iff C1 & C2 == C2
     //       C2+1 is a power of 2
     if (ICI.getPredicate() == ICmpInst::ICMP_UGT && LHSI->hasOneUse() &&
@@ -1582,7 +1594,7 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
                             Builder->CreateAnd(LHSI->getOperand(0), -RHSV),
                             ConstantExpr::getNeg(LHSC));
 
-      // X-C1 >u C2 -> (X & ~C2) == C1
+      // X-C1 >u C2 -> (X & ~C2) != C1
       //   iff C1 & C2 == 0
       //       C2+1 is a power of 2
       if (ICI.getPredicate() == ICmpInst::ICMP_UGT && LHSI->hasOneUse() &&