Revert r245635, "[InstCombine] Transform A & (L - 1) u< L --> L != 0"

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

diff --git a/lib/Transforms/InstCombine/InstCombineCompares.cpp b/lib/Transforms/InstCombine/InstCombineCompares.cpp
index 010b7b57c3e7e56d931e2b78f4f20ddc10236842..9ce1c3fc41b302126f33943cd0d1610a0c3b8749 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineCompares.cpp
+++ b/lib/Transforms/InstCombine/InstCombineCompares.cpp
@@ -1447,6 +1447,23 @@ Instruction *InstCombiner::visitICmpInstWithInstAndIntCst(ICmpInst &ICI,
           ICI.getPredicate() == ICmpInst::ICMP_EQ ? ICmpInst::ICMP_UGT
                                                   : ICmpInst::ICMP_ULE,
           LHSI->getOperand(0), SubOne(RHS));
+
+    // (icmp eq (and %A, C), 0) -> (icmp sgt (trunc %A), -1)
+    //   iff C is a power of 2
+    if (ICI.isEquality() && LHSI->hasOneUse() && match(RHS, m_Zero())) {
+      if (auto *CI = dyn_cast<ConstantInt>(LHSI->getOperand(1))) {
+        const APInt &AI = CI->getValue();
+        int32_t ExactLogBase2 = AI.exactLogBase2();
+        if (ExactLogBase2 != -1 && DL.isLegalInteger(ExactLogBase2 + 1)) {
+          Type *NTy = IntegerType::get(ICI.getContext(), ExactLogBase2 + 1);
+          Value *Trunc = Builder->CreateTrunc(LHSI->getOperand(0), NTy);
+          return new ICmpInst(ICI.getPredicate() == ICmpInst::ICMP_EQ
+                                  ? ICmpInst::ICMP_SGE
+                                  : ICmpInst::ICMP_SLT,
+                              Trunc, Constant::getNullValue(NTy));
+        }
+      }
+    }
     break;
 
   case Instruction::Or: {
@@ -2112,9 +2129,8 @@ static Instruction *ProcessUGT_ADDCST_ADD(ICmpInst &I, Value *A, Value *B,
 bool InstCombiner::OptimizeOverflowCheck(OverflowCheckFlavor OCF, Value *LHS,
                                          Value *RHS, Instruction &OrigI,
                                          Value *&Result, Constant *&Overflow) {
-  assert((!OrigI.isCommutative() ||
-          !(isa<Constant>(LHS) && !isa<Constant>(RHS))) &&
-         "call with a constant RHS if possible!");
+  if (OrigI.isCommutative() && isa<Constant>(LHS) && !isa<Constant>(RHS))
+    std::swap(LHS, RHS);
 
   auto SetResult = [&](Value *OpResult, Constant *OverflowVal, bool ReuseName) {
     Result = OpResult;
@@ -3928,8 +3944,8 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
 
   Value *Op0 = I.getOperand(0), *Op1 = I.getOperand(1);
 
-  if (Value *V =
-          SimplifyFCmpInst(I.getPredicate(), Op0, Op1, DL, TLI, DT, AC, &I))
+  if (Value *V = SimplifyFCmpInst(I.getPredicate(), Op0, Op1,
+                                  I.getFastMathFlags(), DL, TLI, DT, AC, &I))
     return ReplaceInstUsesWith(I, V);
 
   // Simplify 'fcmp pred X, X'