From bb89710dddf967199dfc56e8bf5d28b0003f2ee6 Mon Sep 17 00:00:00 2001 From: Chris Lattner Date: Sun, 26 Dec 2010 20:15:01 +0000 Subject: move isBytewiseValue out to ValueTracking.h/cpp git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122565 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/MemCpyOptimizer.cpp | 69 +------------------------------ 1 file changed, 1 insertion(+), 68 deletions(-) (limited to 'lib/Transforms/Scalar/MemCpyOptimizer.cpp') diff --git a/lib/Transforms/Scalar/MemCpyOptimizer.cpp b/lib/Transforms/Scalar/MemCpyOptimizer.cpp index a927207f66..00ee145785 100644 --- a/lib/Transforms/Scalar/MemCpyOptimizer.cpp +++ b/lib/Transforms/Scalar/MemCpyOptimizer.cpp @@ -22,6 +22,7 @@ #include "llvm/Analysis/Dominators.h" #include "llvm/Analysis/AliasAnalysis.h" #include "llvm/Analysis/MemoryDependenceAnalysis.h" +#include "llvm/Analysis/ValueTracking.h" #include "llvm/Support/Debug.h" #include "llvm/Support/GetElementPtrTypeIterator.h" #include "llvm/Support/raw_ostream.h" @@ -34,74 +35,6 @@ STATISTIC(NumMemSetInfer, "Number of memsets inferred"); STATISTIC(NumMoveToCpy, "Number of memmoves converted to memcpy"); STATISTIC(NumCpyToSet, "Number of memcpys converted to memset"); -/// isBytewiseValue - If the specified value can be set by repeating the same -/// byte in memory, return the i8 value that it is represented with. This is -/// true for all i8 values obviously, but is also true for i32 0, i32 -1, -/// i16 0xF0F0, double 0.0 etc. If the value can't be handled with a repeated -/// byte store (e.g. i16 0x1234), return null. -static Value *isBytewiseValue(Value *V) { - // All byte-wide stores are splatable, even of arbitrary variables. - if (V->getType()->isIntegerTy(8)) return V; - - // Constant float and double values can be handled as integer values if the - // corresponding integer value is "byteable". An important case is 0.0. - if (ConstantFP *CFP = dyn_cast(V)) { - if (CFP->getType()->isFloatTy()) - V = ConstantExpr::getBitCast(CFP, Type::getInt32Ty(V->getContext())); - if (CFP->getType()->isDoubleTy()) - V = ConstantExpr::getBitCast(CFP, Type::getInt64Ty(V->getContext())); - // Don't handle long double formats, which have strange constraints. - } - - // We can handle constant integers that are power of two in size and a - // multiple of 8 bits. - if (ConstantInt *CI = dyn_cast(V)) { - unsigned Width = CI->getBitWidth(); - if (isPowerOf2_32(Width) && Width > 8) { - // We can handle this value if the recursive binary decomposition is the - // same at all levels. - APInt Val = CI->getValue(); - APInt Val2; - while (Val.getBitWidth() != 8) { - unsigned NextWidth = Val.getBitWidth()/2; - Val2 = Val.lshr(NextWidth); - Val2 = Val2.trunc(Val.getBitWidth()/2); - Val = Val.trunc(Val.getBitWidth()/2); - - // If the top/bottom halves aren't the same, reject it. - if (Val != Val2) - return 0; - } - return ConstantInt::get(V->getContext(), Val); - } - } - - // A ConstantArray is splatable if all its members are equal and also - // splatable. - if (ConstantArray *CA = dyn_cast(V)) { - if (CA->getNumOperands() == 0) - return 0; - - Value *Val = isBytewiseValue(CA->getOperand(0)); - if (!Val) - return 0; - - for (unsigned I = 1, E = CA->getNumOperands(); I != E; ++I) - if (CA->getOperand(I-1) != CA->getOperand(I)) - return 0; - - return Val; - } - - // Conceptually, we could handle things like: - // %a = zext i8 %X to i16 - // %b = shl i16 %a, 8 - // %c = or i16 %a, %b - // but until there is an example that actually needs this, it doesn't seem - // worth worrying about. - return 0; -} - static int64_t GetOffsetFromIndex(const GetElementPtrInst *GEP, unsigned Idx, bool &VariableIdxFound, TargetData &TD) { // Skip over the first indices. -- cgit v1.2.3