CodeGenPrep: preserve inbounds attribute when sinking GEPs.
Targets can potentially emit more efficient code if they know address
computations never overflow. For example ILP32 code on AArch64 (which only has
64-bit address computation) can ignore the possibility of overflow with this
extra information.
llvm-svn: 355926
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 1d61d32..e70e4ee 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -2073,6 +2073,7 @@
Value *BaseReg = nullptr;
Value *ScaledReg = nullptr;
Value *OriginalValue = nullptr;
+ bool InBounds = true;
enum FieldName {
NoField = 0x00,
@@ -2084,6 +2085,7 @@
MultipleFields = 0xff
};
+
ExtAddrMode() = default;
void print(raw_ostream &OS) const;
@@ -2102,6 +2104,10 @@
ScaledReg->getType() != other.ScaledReg->getType())
return MultipleFields;
+ // Conservatively reject 'inbounds' mismatches.
+ if (InBounds != other.InBounds)
+ return MultipleFields;
+
// Check each field to see if it differs.
unsigned Result = NoField;
if (BaseReg != other.BaseReg)
@@ -2200,6 +2206,8 @@
void ExtAddrMode::print(raw_ostream &OS) const {
bool NeedPlus = false;
OS << "[";
+ if (InBounds)
+ OS << "inbounds ";
if (BaseGV) {
OS << (NeedPlus ? " + " : "")
<< "GV:";
@@ -3498,6 +3506,7 @@
ConstantInt *CI = nullptr; Value *AddLHS = nullptr;
if (isa<Instruction>(ScaleReg) && // not a constant expr.
match(ScaleReg, m_Add(m_Value(AddLHS), m_ConstantInt(CI)))) {
+ TestAddrMode.InBounds = false;
TestAddrMode.ScaledReg = AddLHS;
TestAddrMode.BaseOffs += CI->getSExtValue()*TestAddrMode.Scale;
@@ -4072,6 +4081,7 @@
TypePromotionTransaction::ConstRestorationPt LastKnownGood =
TPT.getRestorationPoint();
+ AddrMode.InBounds = false;
if (matchAddr(AddrInst->getOperand(1), Depth+1) &&
matchAddr(AddrInst->getOperand(0), Depth+1))
return true;
@@ -4098,6 +4108,7 @@
case Instruction::Mul:
case Instruction::Shl: {
// Can only handle X*C and X << C.
+ AddrMode.InBounds = false;
ConstantInt *RHS = dyn_cast<ConstantInt>(AddrInst->getOperand(1));
if (!RHS || RHS->getBitWidth() > 64)
return false;
@@ -4149,8 +4160,11 @@
if (ConstantOffset == 0 ||
TLI.isLegalAddressingMode(DL, AddrMode, AccessTy, AddrSpace)) {
// Check to see if we can fold the base pointer in too.
- if (matchAddr(AddrInst->getOperand(0), Depth+1))
+ if (matchAddr(AddrInst->getOperand(0), Depth+1)) {
+ if (!cast<GEPOperator>(AddrInst)->isInBounds())
+ AddrMode.InBounds = false;
return true;
+ }
} else if (EnableGEPOffsetSplit && isa<GetElementPtrInst>(AddrInst) &&
TLI.shouldConsiderGEPOffsetSplit() && Depth == 0 &&
ConstantOffset > 0) {
@@ -4186,6 +4200,8 @@
// See if the scale and offset amount is valid for this target.
AddrMode.BaseOffs += ConstantOffset;
+ if (!cast<GEPOperator>(AddrInst)->isInBounds())
+ AddrMode.InBounds = false;
// Match the base operand of the GEP.
if (!matchAddr(AddrInst->getOperand(0), Depth+1)) {
@@ -4871,7 +4887,11 @@
// SDAG consecutive load/store merging.
if (ResultPtr->getType() != I8PtrTy)
ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
- ResultPtr = Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
+ ResultPtr =
+ AddrMode.InBounds
+ ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex,
+ "sunkaddr")
+ : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
}
ResultIndex = V;
@@ -4882,7 +4902,11 @@
} else {
if (ResultPtr->getType() != I8PtrTy)
ResultPtr = Builder.CreatePointerCast(ResultPtr, I8PtrTy);
- SunkAddr = Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
+ SunkAddr =
+ AddrMode.InBounds
+ ? Builder.CreateInBoundsGEP(I8Ty, ResultPtr, ResultIndex,
+ "sunkaddr")
+ : Builder.CreateGEP(I8Ty, ResultPtr, ResultIndex, "sunkaddr");
}
if (SunkAddr->getType() != Addr->getType())