Revert r310869 "[InstSimplify][InstCombine] Modify the interface of decomposeBitTestICmp and use it in the InstSimplify"
Failed to add the two files that moved. And then added an extra change I didn't mean to while trying to fix that. Reverting everything.
llvm-svn: 310873
diff --git a/llvm/lib/Transforms/Utils/CmpInstAnalysis.cpp b/llvm/lib/Transforms/Utils/CmpInstAnalysis.cpp
new file mode 100644
index 0000000..d9294c4
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/CmpInstAnalysis.cpp
@@ -0,0 +1,108 @@
+//===- CmpInstAnalysis.cpp - Utils to help fold compares ---------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file holds routines to help analyse compare instructions
+// and fold them into constants or other compare instructions
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Utils/CmpInstAnalysis.h"
+#include "llvm/IR/Constants.h"
+#include "llvm/IR/Instructions.h"
+
+using namespace llvm;
+
+unsigned llvm::getICmpCode(const ICmpInst *ICI, bool InvertPred) {
+ ICmpInst::Predicate Pred = InvertPred ? ICI->getInversePredicate()
+ : ICI->getPredicate();
+ switch (Pred) {
+ // False -> 0
+ case ICmpInst::ICMP_UGT: return 1; // 001
+ case ICmpInst::ICMP_SGT: return 1; // 001
+ case ICmpInst::ICMP_EQ: return 2; // 010
+ case ICmpInst::ICMP_UGE: return 3; // 011
+ case ICmpInst::ICMP_SGE: return 3; // 011
+ case ICmpInst::ICMP_ULT: return 4; // 100
+ case ICmpInst::ICMP_SLT: return 4; // 100
+ case ICmpInst::ICMP_NE: return 5; // 101
+ case ICmpInst::ICMP_ULE: return 6; // 110
+ case ICmpInst::ICMP_SLE: return 6; // 110
+ // True -> 7
+ default:
+ llvm_unreachable("Invalid ICmp predicate!");
+ }
+}
+
+Value *llvm::getICmpValue(bool Sign, unsigned Code, Value *LHS, Value *RHS,
+ CmpInst::Predicate &NewICmpPred) {
+ switch (Code) {
+ default: llvm_unreachable("Illegal ICmp code!");
+ case 0: // False.
+ return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 0);
+ case 1: NewICmpPred = Sign ? ICmpInst::ICMP_SGT : ICmpInst::ICMP_UGT; break;
+ case 2: NewICmpPred = ICmpInst::ICMP_EQ; break;
+ case 3: NewICmpPred = Sign ? ICmpInst::ICMP_SGE : ICmpInst::ICMP_UGE; break;
+ case 4: NewICmpPred = Sign ? ICmpInst::ICMP_SLT : ICmpInst::ICMP_ULT; break;
+ case 5: NewICmpPred = ICmpInst::ICMP_NE; break;
+ case 6: NewICmpPred = Sign ? ICmpInst::ICMP_SLE : ICmpInst::ICMP_ULE; break;
+ case 7: // True.
+ return ConstantInt::get(CmpInst::makeCmpResultType(LHS->getType()), 1);
+ }
+ return nullptr;
+}
+
+bool llvm::PredicatesFoldable(ICmpInst::Predicate p1, ICmpInst::Predicate p2) {
+ return (CmpInst::isSigned(p1) == CmpInst::isSigned(p2)) ||
+ (CmpInst::isSigned(p1) && ICmpInst::isEquality(p2)) ||
+ (CmpInst::isSigned(p2) && ICmpInst::isEquality(p1));
+}
+
+bool llvm::decomposeBitTestICmp(const ICmpInst *I, CmpInst::Predicate &Pred,
+ Value *&X, Value *&Y, Value *&Z) {
+ ConstantInt *C = dyn_cast<ConstantInt>(I->getOperand(1));
+ if (!C)
+ return false;
+
+ switch (I->getPredicate()) {
+ default:
+ return false;
+ case ICmpInst::ICMP_SLT:
+ // X < 0 is equivalent to (X & SignMask) != 0.
+ if (!C->isZero())
+ return false;
+ Y = ConstantInt::get(I->getContext(), APInt::getSignMask(C->getBitWidth()));
+ Pred = ICmpInst::ICMP_NE;
+ break;
+ case ICmpInst::ICMP_SGT:
+ // X > -1 is equivalent to (X & SignMask) == 0.
+ if (!C->isMinusOne())
+ return false;
+ Y = ConstantInt::get(I->getContext(), APInt::getSignMask(C->getBitWidth()));
+ Pred = ICmpInst::ICMP_EQ;
+ break;
+ case ICmpInst::ICMP_ULT:
+ // X <u 2^n is equivalent to (X & ~(2^n-1)) == 0.
+ if (!C->getValue().isPowerOf2())
+ return false;
+ Y = ConstantInt::get(I->getContext(), -C->getValue());
+ Pred = ICmpInst::ICMP_EQ;
+ break;
+ case ICmpInst::ICMP_UGT:
+ // X >u 2^n-1 is equivalent to (X & ~(2^n-1)) != 0.
+ if (!(C->getValue() + 1).isPowerOf2())
+ return false;
+ Y = ConstantInt::get(I->getContext(), ~C->getValue());
+ Pred = ICmpInst::ICMP_NE;
+ break;
+ }
+
+ X = I->getOperand(0);
+ Z = ConstantInt::getNullValue(C->getType());
+ return true;
+}