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-rw-r--r--llvm/lib/Transforms/Scalar/GVN.cpp176
1 files changed, 118 insertions, 58 deletions
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index 33c387cb71c..f40d34f2488 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -111,10 +111,11 @@ namespace {
uint32_t nextValueNumber;
Expression create_expression(Instruction* I);
+ Expression create_intrinsic_expression(CallInst *C, uint32_t opcode,
+ bool IsCommutative);
Expression create_cmp_expression(unsigned Opcode,
CmpInst::Predicate Predicate,
Value *LHS, Value *RHS);
- Expression create_extractvalue_expression(ExtractValueInst* EI);
uint32_t lookup_or_add_call(CallInst* C);
public:
ValueTable() : nextValueNumber(1) { }
@@ -193,6 +194,29 @@ Expression ValueTable::create_expression(Instruction *I) {
return e;
}
+Expression ValueTable::create_intrinsic_expression(CallInst *C, uint32_t opcode,
+ bool IsCommutative) {
+ Expression e;
+ e.opcode = opcode;
+ StructType *ST = cast<StructType>(C->getType());
+ assert(ST);
+ e.type = *ST->element_begin();
+
+ for (unsigned i = 0, ei = C->getNumArgOperands(); i < ei; ++i)
+ e.varargs.push_back(lookup_or_add(C->getArgOperand(i)));
+ if (IsCommutative) {
+ // Ensure that commutative instructions that only differ by a permutation
+ // of their operands get the same value number by sorting the operand value
+ // numbers. Since all commutative instructions have two operands it is more
+ // efficient to sort by hand rather than using, say, std::sort.
+ assert(C->getNumArgOperands() == 2 && "Unsupported commutative instruction!");
+ if (e.varargs[0] > e.varargs[1])
+ std::swap(e.varargs[0], e.varargs[1]);
+ }
+
+ return e;
+}
+
Expression ValueTable::create_cmp_expression(unsigned Opcode,
CmpInst::Predicate Predicate,
Value *LHS, Value *RHS) {
@@ -212,58 +236,6 @@ Expression ValueTable::create_cmp_expression(unsigned Opcode,
return e;
}
-Expression ValueTable::create_extractvalue_expression(ExtractValueInst *EI) {
- assert(EI != 0 && "Not an ExtractValueInst?");
- Expression e;
- e.type = EI->getType();
- e.opcode = 0;
-
- IntrinsicInst *I = dyn_cast<IntrinsicInst>(EI->getAggregateOperand());
- if (I != 0 && EI->getNumIndices() == 1 && *EI->idx_begin() == 0 ) {
- // EI might be an extract from one of our recognised intrinsics. If it
- // is we'll synthesize a semantically equivalent expression instead on
- // an extract value expression.
- switch (I->getIntrinsicID()) {
- case Intrinsic::sadd_with_overflow:
- case Intrinsic::uadd_with_overflow:
- e.opcode = Instruction::Add;
- break;
- case Intrinsic::ssub_with_overflow:
- case Intrinsic::usub_with_overflow:
- e.opcode = Instruction::Sub;
- break;
- case Intrinsic::smul_with_overflow:
- case Intrinsic::umul_with_overflow:
- e.opcode = Instruction::Mul;
- break;
- default:
- break;
- }
-
- if (e.opcode != 0) {
- // Intrinsic recognized. Grab its args to finish building the expression.
- assert(I->getNumArgOperands() == 2 &&
- "Expect two args for recognised intrinsics.");
- e.varargs.push_back(lookup_or_add(I->getArgOperand(0)));
- e.varargs.push_back(lookup_or_add(I->getArgOperand(1)));
- return e;
- }
- }
-
- // Not a recognised intrinsic. Fall back to producing an extract value
- // expression.
- e.opcode = EI->getOpcode();
- for (Instruction::op_iterator OI = EI->op_begin(), OE = EI->op_end();
- OI != OE; ++OI)
- e.varargs.push_back(lookup_or_add(*OI));
-
- for (ExtractValueInst::idx_iterator II = EI->idx_begin(), IE = EI->idx_end();
- II != IE; ++II)
- e.varargs.push_back(*II);
-
- return e;
-}
-
//===----------------------------------------------------------------------===//
// ValueTable External Functions
//===----------------------------------------------------------------------===//
@@ -397,8 +369,29 @@ uint32_t ValueTable::lookup_or_add(Value *V) {
Instruction* I = cast<Instruction>(V);
Expression exp;
switch (I->getOpcode()) {
- case Instruction::Call:
- return lookup_or_add_call(cast<CallInst>(I));
+ case Instruction::Call: {
+ CallInst *C = cast<CallInst>(I);
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(C)) {
+ switch (II->getIntrinsicID()) {
+ case Intrinsic::sadd_with_overflow:
+ case Intrinsic::uadd_with_overflow:
+ exp = create_intrinsic_expression(C, Instruction::Add, true);
+ break;
+ case Intrinsic::ssub_with_overflow:
+ case Intrinsic::usub_with_overflow:
+ exp = create_intrinsic_expression(C, Instruction::Sub, false);
+ break;
+ case Intrinsic::smul_with_overflow:
+ case Intrinsic::umul_with_overflow:
+ exp = create_intrinsic_expression(C, Instruction::Mul, true);
+ break;
+ default:
+ return lookup_or_add_call(C);
+ }
+ } else {
+ return lookup_or_add_call(C);
+ }
+ } break;
case Instruction::Add:
case Instruction::FAdd:
case Instruction::Sub:
@@ -437,10 +430,8 @@ uint32_t ValueTable::lookup_or_add(Value *V) {
case Instruction::ShuffleVector:
case Instruction::InsertValue:
case Instruction::GetElementPtr:
- exp = create_expression(I);
- break;
case Instruction::ExtractValue:
- exp = create_extractvalue_expression(cast<ExtractValueInst>(I));
+ exp = create_expression(I);
break;
default:
valueNumbering[V] = nextValueNumber;
@@ -2189,6 +2180,54 @@ bool GVN::propagateEquality(Value *LHS, Value *RHS,
return Changed;
}
+static bool normalOpAfterIntrinsic(Instruction *I, Value *Repl)
+{
+ switch (I->getOpcode()) {
+ case Instruction::Add:
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Repl))
+ return II->getIntrinsicID() == Intrinsic::sadd_with_overflow
+ || II->getIntrinsicID() == Intrinsic::uadd_with_overflow;
+ return false;
+ case Instruction::Sub:
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Repl))
+ return II->getIntrinsicID() == Intrinsic::ssub_with_overflow
+ || II->getIntrinsicID() == Intrinsic::usub_with_overflow;
+ return false;
+ case Instruction::Mul:
+ if (IntrinsicInst *II = dyn_cast<IntrinsicInst>(Repl))
+ return II->getIntrinsicID() == Intrinsic::smul_with_overflow
+ || II->getIntrinsicID() == Intrinsic::umul_with_overflow;
+ return false;
+ default:
+ return false;
+ }
+}
+
+static bool intrinsicAterNormalOp(Instruction *I, Value *Repl)
+{
+ IntrinsicInst *II = dyn_cast<IntrinsicInst>(I);
+ if (!II)
+ return false;
+
+ Instruction *RI = dyn_cast<Instruction>(Repl);
+ if (!RI)
+ return false;
+
+ switch (RI->getOpcode()) {
+ case Instruction::Add:
+ return II->getIntrinsicID() == Intrinsic::sadd_with_overflow
+ || II->getIntrinsicID() == Intrinsic::uadd_with_overflow;
+ case Instruction::Sub:
+ return II->getIntrinsicID() == Intrinsic::ssub_with_overflow
+ || II->getIntrinsicID() == Intrinsic::usub_with_overflow;
+ case Instruction::Mul:
+ return II->getIntrinsicID() == Intrinsic::smul_with_overflow
+ || II->getIntrinsicID() == Intrinsic::umul_with_overflow;
+ default:
+ return false;
+ }
+}
+
/// processInstruction - When calculating availability, handle an instruction
/// by inserting it into the appropriate sets
bool GVN::processInstruction(Instruction *I) {
@@ -2302,6 +2341,27 @@ bool GVN::processInstruction(Instruction *I) {
return false;
}
+ if (normalOpAfterIntrinsic(I, repl)) {
+ // An intrinsic followed by a normal operation (e.g. sadd_with_overflow
+ // followed by a sadd): replace the second instruction with an extract.
+ IntrinsicInst *II = cast<IntrinsicInst>(repl);
+ assert(II);
+ repl = ExtractValueInst::Create(II, 0, I->getName() + ".repl", I);
+ } else if (intrinsicAterNormalOp(I, repl)) {
+ // A normal operation followed by an intrinsic (e.g. sadd followed by a
+ // sadd_with_overflow).
+ // Clone the intrinsic, and insert it before the replacing instruction. Then
+ // replace the (current) instruction with the cloned one. In a subsequent
+ // run, the original replacement (the non-intrinsic) will be be replaced by
+ // the new intrinsic.
+ Instruction *RI = dyn_cast<Instruction>(repl);
+ assert(RI);
+ Instruction *newIntrinsic = I->clone();
+ newIntrinsic->setName(I->getName() + ".repl");
+ newIntrinsic->insertBefore(RI);
+ repl = newIntrinsic;
+ }
+
// Remove it!
patchAndReplaceAllUsesWith(I, repl);
if (MD && repl->getType()->getScalarType()->isPointerTy())
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