diff options
| -rw-r--r-- | backend/src/llvm/ExpandConstantExpr.cpp | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/backend/src/llvm/ExpandConstantExpr.cpp b/backend/src/llvm/ExpandConstantExpr.cpp index 54b8b16d..2da765e1 100644 --- a/backend/src/llvm/ExpandConstantExpr.cpp +++ b/backend/src/llvm/ExpandConstantExpr.cpp @@ -78,6 +78,7 @@ #include <map> +#include "llvm/IR/IRBuilder.h" #include "llvm/IR/Constants.h" #include "llvm/IR/Function.h" #include "llvm/IR/Instructions.h" @@ -110,6 +111,43 @@ static Value *expandConstantExpr(Instruction *InsertPt, ConstantExpr *Expr) { return NewInst; } +// For a constant vector, it may contain some constant expressions. +// We need to expand each expressions then recreate this vector by +// using InsertElement instruction. Thus we can eliminate all the +// constant expressions. +static Value *expandConstantVector(Instruction *InsertPt, ConstantVector *CV) { + int elemNum = CV->getType()->getNumElements(); + Type *IntTy = IntegerType::get(CV->getContext(), 32); + + BasicBlock::iterator InsertPos(InsertPt); + IRBuilder<> IRB(--InsertPos); + Value *vec = UndefValue::get(CV->getType()); + for (int i = 0; i < elemNum; i++) { + Value *idx = ConstantInt::get(IntTy, i); + if (dyn_cast<ConstantVector>(CV->getOperand(i))) + vec = IRB.CreateInsertElement(vec, expandConstantVector(InsertPt, dyn_cast<ConstantVector>(CV->getOperand(i))), idx); + else if (dyn_cast<ConstantExpr>(CV->getOperand(i))) + vec = IRB.CreateInsertElement(vec, expandConstantExpr(InsertPt, dyn_cast<ConstantExpr>(CV->getOperand(i))), idx); + else + vec = IRB.CreateInsertElement(vec, CV->getOperand(i), idx); + } + return vec; +} + +// Whether a constant vector contains constant expression which need to expand. +static bool needExpand(ConstantVector *CV) { + int elemNum = CV->getType()->getNumElements(); + for (int i = 0; i < elemNum; i++) { + Constant *C = CV->getOperand(i); + if (dyn_cast<ConstantExpr>(C)) + return true; + if (dyn_cast<ConstantVector>(C)) + if (needExpand(dyn_cast<ConstantVector>(C))) + return true; + } + return false; +} + static bool expandInstruction(Instruction *Inst) { // A landingpad can only accept ConstantExprs, so it should remain // unmodified. @@ -124,6 +162,14 @@ static bool expandInstruction(Instruction *Inst) { Use *U = &Inst->getOperandUse(OpNum); PhiSafeReplaceUses(U, expandConstantExpr(PhiSafeInsertPt(U), Expr)); } + else { + ConstantVector *CV = dyn_cast<ConstantVector>(Inst->getOperand(OpNum)); + if (CV && needExpand(CV)) { + Modified = true; + Use *U = &Inst->getOperandUse(OpNum); + PhiSafeReplaceUses(U, expandConstantVector(PhiSafeInsertPt(U), CV)); + } + } } return Modified; } |