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-rw-r--r--contrib/llvm/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp59
1 files changed, 57 insertions, 2 deletions
diff --git a/contrib/llvm/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp b/contrib/llvm/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp
index 232a611..2d0098b 100644
--- a/contrib/llvm/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp
+++ b/contrib/llvm/lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp
@@ -12,6 +12,8 @@
//===----------------------------------------------------------------------===//
#include "NVPTXISelDAGToDAG.h"
+#include "NVPTXUtilities.h"
+#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/IR/Instructions.h"
#include "llvm/Support/CommandLine.h"
@@ -530,7 +532,7 @@ static unsigned int getCodeAddrSpace(MemSDNode *N) {
if (!Src)
return NVPTX::PTXLdStInstCode::GENERIC;
- if (const PointerType *PT = dyn_cast<PointerType>(Src->getType())) {
+ if (auto *PT = dyn_cast<PointerType>(Src->getType())) {
switch (PT->getAddressSpace()) {
case llvm::ADDRESS_SPACE_LOCAL: return NVPTX::PTXLdStInstCode::LOCAL;
case llvm::ADDRESS_SPACE_GLOBAL: return NVPTX::PTXLdStInstCode::GLOBAL;
@@ -544,6 +546,39 @@ static unsigned int getCodeAddrSpace(MemSDNode *N) {
return NVPTX::PTXLdStInstCode::GENERIC;
}
+static bool canLowerToLDG(MemSDNode *N, const NVPTXSubtarget &Subtarget,
+ unsigned CodeAddrSpace, MachineFunction *F) {
+ // To use non-coherent caching, the load has to be from global
+ // memory and we have to prove that the memory area is not written
+ // to anywhere for the duration of the kernel call, not even after
+ // the load.
+ //
+ // To ensure that there are no writes to the memory, we require the
+ // underlying pointer to be a noalias (__restrict) kernel parameter
+ // that is never used for a write. We can only do this for kernel
+ // functions since from within a device function, we cannot know if
+ // there were or will be writes to the memory from the caller - or we
+ // could, but then we would have to do inter-procedural analysis.
+ if (!Subtarget.hasLDG() || CodeAddrSpace != NVPTX::PTXLdStInstCode::GLOBAL ||
+ !isKernelFunction(*F->getFunction())) {
+ return false;
+ }
+
+ // We use GetUnderlyingObjects() here instead of
+ // GetUnderlyingObject() mainly because the former looks through phi
+ // nodes while the latter does not. We need to look through phi
+ // nodes to handle pointer induction variables.
+ SmallVector<Value *, 8> Objs;
+ GetUnderlyingObjects(const_cast<Value *>(N->getMemOperand()->getValue()),
+ Objs, F->getDataLayout());
+ for (Value *Obj : Objs) {
+ auto *A = dyn_cast<const Argument>(Obj);
+ if (!A || !A->onlyReadsMemory() || !A->hasNoAliasAttr()) return false;
+ }
+
+ return true;
+}
+
SDNode *NVPTXDAGToDAGISel::SelectIntrinsicNoChain(SDNode *N) {
unsigned IID = cast<ConstantSDNode>(N->getOperand(0))->getZExtValue();
switch (IID) {
@@ -638,6 +673,10 @@ SDNode *NVPTXDAGToDAGISel::SelectLoad(SDNode *N) {
// Address Space Setting
unsigned int codeAddrSpace = getCodeAddrSpace(LD);
+ if (canLowerToLDG(LD, *Subtarget, codeAddrSpace, MF)) {
+ return SelectLDGLDU(N);
+ }
+
// Volatile Setting
// - .volatile is only availalble for .global and .shared
bool isVolatile = LD->isVolatile();
@@ -872,6 +911,10 @@ SDNode *NVPTXDAGToDAGISel::SelectLoadVector(SDNode *N) {
// Address Space Setting
unsigned int CodeAddrSpace = getCodeAddrSpace(MemSD);
+ if (canLowerToLDG(MemSD, *Subtarget, CodeAddrSpace, MF)) {
+ return SelectLDGLDU(N);
+ }
+
// Volatile Setting
// - .volatile is only availalble for .global and .shared
bool IsVolatile = MemSD->isVolatile();
@@ -1425,6 +1468,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
switch (N->getOpcode()) {
default:
return nullptr;
+ case ISD::LOAD:
case ISD::INTRINSIC_W_CHAIN:
if (IsLDG) {
switch (EltVT.getSimpleVT().SimpleTy) {
@@ -1474,6 +1518,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
}
}
break;
+ case NVPTXISD::LoadV2:
case NVPTXISD::LDGV2:
switch (EltVT.getSimpleVT().SimpleTy) {
default:
@@ -1522,6 +1567,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
break;
}
break;
+ case NVPTXISD::LoadV4:
case NVPTXISD::LDGV4:
switch (EltVT.getSimpleVT().SimpleTy) {
default:
@@ -1563,6 +1609,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
switch (N->getOpcode()) {
default:
return nullptr;
+ case ISD::LOAD:
case ISD::INTRINSIC_W_CHAIN:
if (IsLDG) {
switch (EltVT.getSimpleVT().SimpleTy) {
@@ -1612,6 +1659,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
}
}
break;
+ case NVPTXISD::LoadV2:
case NVPTXISD::LDGV2:
switch (EltVT.getSimpleVT().SimpleTy) {
default:
@@ -1660,6 +1708,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
break;
}
break;
+ case NVPTXISD::LoadV4:
case NVPTXISD::LDGV4:
switch (EltVT.getSimpleVT().SimpleTy) {
default:
@@ -1707,6 +1756,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
switch (N->getOpcode()) {
default:
return nullptr;
+ case ISD::LOAD:
case ISD::INTRINSIC_W_CHAIN:
if (IsLDG) {
switch (EltVT.getSimpleVT().SimpleTy) {
@@ -1756,6 +1806,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
}
}
break;
+ case NVPTXISD::LoadV2:
case NVPTXISD::LDGV2:
switch (EltVT.getSimpleVT().SimpleTy) {
default:
@@ -1804,6 +1855,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
break;
}
break;
+ case NVPTXISD::LoadV4:
case NVPTXISD::LDGV4:
switch (EltVT.getSimpleVT().SimpleTy) {
default:
@@ -1845,6 +1897,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
switch (N->getOpcode()) {
default:
return nullptr;
+ case ISD::LOAD:
case ISD::INTRINSIC_W_CHAIN:
if (IsLDG) {
switch (EltVT.getSimpleVT().SimpleTy) {
@@ -1894,6 +1947,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
}
}
break;
+ case NVPTXISD::LoadV2:
case NVPTXISD::LDGV2:
switch (EltVT.getSimpleVT().SimpleTy) {
default:
@@ -1942,6 +1996,7 @@ SDNode *NVPTXDAGToDAGISel::SelectLDGLDU(SDNode *N) {
break;
}
break;
+ case NVPTXISD::LoadV4:
case NVPTXISD::LDGV4:
switch (EltVT.getSimpleVT().SimpleTy) {
default:
@@ -5039,7 +5094,7 @@ bool NVPTXDAGToDAGISel::ChkMemSDNodeAddressSpace(SDNode *N,
}
if (!Src)
return false;
- if (const PointerType *PT = dyn_cast<PointerType>(Src->getType()))
+ if (auto *PT = dyn_cast<PointerType>(Src->getType()))
return (PT->getAddressSpace() == spN);
return false;
}
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