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 d843842cb3a0c49cf11421a65b4aa7dd50f5b5af..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)
@@ -1277,6 +1289,15 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
               return Res;
           }
     }
+
+    // X & -C == -C -> X >  u ~C
+    // X & -C != -C -> X <= u ~C
+    //   iff C is a power of 2
+    if (ICI.isEquality() && RHS == LHSI->getOperand(1) && (-RHSV).isPowerOf2())
+      return new ICmpInst(
+          ICI.getPredicate() == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_UGT
+                                                  : ICmpInst::ICMP_ULE,
+          LHSI->getOperand(0), SubOne(RHS));
     break;
 
   case Instruction::Or: {
@@ -1526,7 +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() &&
@@ -1564,13 +1585,23 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
         }
       }
 
-      // X-C1 <u 2 -> (X & -2) == C1
-      //   iff C1 & 1 == 0
+      // X-C1 <u C2 -> (X & -C2) == C1
+      //   iff C1 & (C2-1) == 0
+      //       C2 is a power of 2
       if (ICI.getPredicate() == ICmpInst::ICMP_ULT && LHSI->hasOneUse() &&
-          LHSV[0] == 0 && RHSV == 2)
+          RHSV.isPowerOf2() && (LHSV & (RHSV - 1)) == 0)
         return new ICmpInst(ICmpInst::ICMP_EQ,
                             Builder->CreateAnd(LHSI->getOperand(0), -RHSV),
                             ConstantExpr::getNeg(LHSC));
+
+      // 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() &&
+          (RHSV + 1).isPowerOf2() && (LHSV & RHSV) == 0)
+        return new ICmpInst(ICmpInst::ICMP_NE,
+                            Builder->CreateAnd(LHSI->getOperand(0), ~RHSV),
+                            ConstantExpr::getNeg(LHSC));
     }
     break;
   }
@@ -1732,24 +1763,6 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
       default:
         break;
       }
-
-      // X-C1 <u C2 -> (X & -C2) == C1
-      //   iff C1 & (C2-1) == 0
-      //       C2 is a power of 2
-      if (ICI.getPredicate() == ICmpInst::ICMP_ULT && LHSI->hasOneUse() &&
-          RHSV.isPowerOf2() && (LHSV & (RHSV - 1)) == 0)
-        return new ICmpInst(ICmpInst::ICMP_EQ,
-                            Builder->CreateAnd(LHSI->getOperand(0), -RHSV),
-                            ConstantExpr::getNeg(LHSC));
-
-      // 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() &&
-          (RHSV + 1).isPowerOf2() && (LHSV & RHSV) == 0)
-        return new ICmpInst(ICmpInst::ICMP_NE,
-                            Builder->CreateAnd(LHSI->getOperand(0), ~RHSV),
-                            ConstantExpr::getNeg(LHSC));
     }
   }
   return 0;