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-rw-r--r--llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp6
-rw-r--r--llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp55
-rw-r--r--llvm/test/CodeGen/WebAssembly/offset.ll198
3 files changed, 250 insertions, 9 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 0872d7a9a22..bc2405b952a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -6843,9 +6843,13 @@ SDValue DAGCombiner::ReduceLoadWidth(SDNode *N) {
uint64_t PtrOff = ShAmt / 8;
unsigned NewAlign = MinAlign(LN0->getAlignment(), PtrOff);
SDLoc DL(LN0);
+ // The original load itself didn't wrap, so an offset within it doesn't.
+ SDNodeFlags Flags;
+ Flags.setNoUnsignedWrap(true);
SDValue NewPtr = DAG.getNode(ISD::ADD, DL,
PtrType, LN0->getBasePtr(),
- DAG.getConstant(PtrOff, DL, PtrType));
+ DAG.getConstant(PtrOff, DL, PtrType),
+ &Flags);
AddToWorklist(NewPtr.getNode());
SDValue Load;
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 94550d60b36..e446a934554 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -1329,12 +1329,18 @@ void SelectionDAGBuilder::visitRet(const ReturnInst &I) {
ComputeValueVTs(TLI, DL, I.getOperand(0)->getType(), ValueVTs, &Offsets);
unsigned NumValues = ValueVTs.size();
+ // An aggregate return value cannot wrap around the address space, so
+ // offsets to its parts don't wrap either.
+ SDNodeFlags Flags;
+ Flags.setNoUnsignedWrap(true);
+
SmallVector<SDValue, 4> Chains(NumValues);
for (unsigned i = 0; i != NumValues; ++i) {
SDValue Add = DAG.getNode(ISD::ADD, getCurSDLoc(),
RetPtr.getValueType(), RetPtr,
DAG.getIntPtrConstant(Offsets[i],
- getCurSDLoc()));
+ getCurSDLoc()),
+ &Flags);
Chains[i] =
DAG.getStore(Chain, getCurSDLoc(),
SDValue(RetOp.getNode(), RetOp.getResNo() + i),
@@ -2994,8 +3000,15 @@ void SelectionDAGBuilder::visitGetElementPtr(const User &I) {
if (Field) {
// N = N + Offset
uint64_t Offset = DL->getStructLayout(StTy)->getElementOffset(Field);
+
+ // In an inbouds GEP with an offset that is nonnegative even when
+ // interpreted as signed, assume there is no unsigned overflow.
+ SDNodeFlags Flags;
+ if (int64_t(Offset) >= 0 && cast<GEPOperator>(I).isInBounds())
+ Flags.setNoUnsignedWrap(true);
+
N = DAG.getNode(ISD::ADD, dl, N.getValueType(), N,
- DAG.getConstant(Offset, dl, N.getValueType()));
+ DAG.getConstant(Offset, dl, N.getValueType()), &Flags);
}
Ty = StTy->getElementType(Field);
@@ -3020,7 +3033,14 @@ void SelectionDAGBuilder::visitGetElementPtr(const User &I) {
SDValue OffsVal = VectorWidth ?
DAG.getConstant(Offs, dl, MVT::getVectorVT(PtrTy, VectorWidth)) :
DAG.getConstant(Offs, dl, PtrTy);
- N = DAG.getNode(ISD::ADD, dl, N.getValueType(), N, OffsVal);
+
+ // In an inbouds GEP with an offset that is nonnegative even when
+ // interpreted as signed, assume there is no unsigned overflow.
+ SDNodeFlags Flags;
+ if (Offs.isNonNegative() && cast<GEPOperator>(I).isInBounds())
+ Flags.setNoUnsignedWrap(true);
+
+ N = DAG.getNode(ISD::ADD, dl, N.getValueType(), N, OffsVal, &Flags);
continue;
}
@@ -3092,10 +3112,13 @@ void SelectionDAGBuilder::visitAlloca(const AllocaInst &I) {
Align = 0;
// Round the size of the allocation up to the stack alignment size
- // by add SA-1 to the size.
+ // by add SA-1 to the size. This doesn't overflow because we're computing
+ // an address inside an alloca.
+ SDNodeFlags Flags;
+ Flags.setNoUnsignedWrap(true);
AllocSize = DAG.getNode(ISD::ADD, dl,
AllocSize.getValueType(), AllocSize,
- DAG.getIntPtrConstant(StackAlign - 1, dl));
+ DAG.getIntPtrConstant(StackAlign - 1, dl), &Flags);
// Mask out the low bits for alignment purposes.
AllocSize = DAG.getNode(ISD::AND, dl,
@@ -3168,6 +3191,11 @@ void SelectionDAGBuilder::visitLoad(const LoadInst &I) {
if (isVolatile)
Root = TLI.prepareVolatileOrAtomicLoad(Root, dl, DAG);
+ // An aggregate load cannot wrap around the address space, so offsets to its
+ // parts don't wrap either.
+ SDNodeFlags Flags;
+ Flags.setNoUnsignedWrap(true);
+
SmallVector<SDValue, 4> Values(NumValues);
SmallVector<SDValue, 4> Chains(std::min(MaxParallelChains, NumValues));
EVT PtrVT = Ptr.getValueType();
@@ -3188,7 +3216,8 @@ void SelectionDAGBuilder::visitLoad(const LoadInst &I) {
}
SDValue A = DAG.getNode(ISD::ADD, dl,
PtrVT, Ptr,
- DAG.getConstant(Offsets[i], dl, PtrVT));
+ DAG.getConstant(Offsets[i], dl, PtrVT),
+ &Flags);
SDValue L = DAG.getLoad(ValueVTs[i], dl, Root,
A, MachinePointerInfo(SV, Offsets[i]), isVolatile,
isNonTemporal, isInvariant, Alignment, AAInfo,
@@ -3243,6 +3272,11 @@ void SelectionDAGBuilder::visitStore(const StoreInst &I) {
AAMDNodes AAInfo;
I.getAAMetadata(AAInfo);
+ // An aggregate load cannot wrap around the address space, so offsets to its
+ // parts don't wrap either.
+ SDNodeFlags Flags;
+ Flags.setNoUnsignedWrap(true);
+
unsigned ChainI = 0;
for (unsigned i = 0; i != NumValues; ++i, ++ChainI) {
// See visitLoad comments.
@@ -3253,7 +3287,7 @@ void SelectionDAGBuilder::visitStore(const StoreInst &I) {
ChainI = 0;
}
SDValue Add = DAG.getNode(ISD::ADD, dl, PtrVT, Ptr,
- DAG.getConstant(Offsets[i], dl, PtrVT));
+ DAG.getConstant(Offsets[i], dl, PtrVT), &Flags);
SDValue St = DAG.getStore(Root, dl,
SDValue(Src.getNode(), Src.getResNo() + i),
Add, MachinePointerInfo(PtrV, Offsets[i]),
@@ -7202,10 +7236,15 @@ TargetLowering::LowerCallTo(TargetLowering::CallLoweringInfo &CLI) const {
ReturnValues.resize(NumValues);
SmallVector<SDValue, 4> Chains(NumValues);
+ // An aggregate return value cannot wrap around the address space, so
+ // offsets to its parts don't wrap either.
+ SDNodeFlags Flags;
+ Flags.setNoUnsignedWrap(true);
+
for (unsigned i = 0; i < NumValues; ++i) {
SDValue Add = CLI.DAG.getNode(ISD::ADD, CLI.DL, PtrVT, DemoteStackSlot,
CLI.DAG.getConstant(Offsets[i], CLI.DL,
- PtrVT));
+ PtrVT), &Flags);
SDValue L = CLI.DAG.getLoad(
RetTys[i], CLI.DL, CLI.Chain, Add,
MachinePointerInfo::getFixedStack(CLI.DAG.getMachineFunction(),
diff --git a/llvm/test/CodeGen/WebAssembly/offset.ll b/llvm/test/CodeGen/WebAssembly/offset.ll
index 75a0bc9ab6c..901801d7dbb 100644
--- a/llvm/test/CodeGen/WebAssembly/offset.ll
+++ b/llvm/test/CodeGen/WebAssembly/offset.ll
@@ -17,6 +17,28 @@ define i32 @load_i32_with_folded_offset(i32* %p) {
ret i32 %t
}
+; With an inbounds gep, we can fold an offset.
+
+; CHECK-LABEL: load_i32_with_folded_gep_offset:
+; CHECK: i32.load $push0=, 24($0){{$}}
+define i32 @load_i32_with_folded_gep_offset(i32* %p) {
+ %s = getelementptr inbounds i32, i32* %p, i32 6
+ %t = load i32, i32* %s
+ ret i32 %t
+}
+
+; We can't fold a negative offset though, even with an inbounds gep.
+
+; CHECK-LABEL: load_i32_with_unfolded_gep_negative_offset:
+; CHECK: i32.const $push0=, -24{{$}}
+; CHECK: i32.add $push1=, $0, $pop0{{$}}
+; CHECK: i32.load $push2=, 0($pop1){{$}}
+define i32 @load_i32_with_unfolded_gep_negative_offset(i32* %p) {
+ %s = getelementptr inbounds i32, i32* %p, i32 -6
+ %t = load i32, i32* %s
+ ret i32 %t
+}
+
; Without nuw, and even with nsw, we can't fold an offset.
; CHECK-LABEL: load_i32_with_unfolded_offset:
@@ -31,6 +53,18 @@ define i32 @load_i32_with_unfolded_offset(i32* %p) {
ret i32 %t
}
+; Without inbounds, we can't fold a gep offset.
+
+; CHECK-LABEL: load_i32_with_unfolded_gep_offset:
+; CHECK: i32.const $push0=, 24{{$}}
+; CHECK: i32.add $push1=, $0, $pop0{{$}}
+; CHECK: i32.load $push2=, 0($pop1){{$}}
+define i32 @load_i32_with_unfolded_gep_offset(i32* %p) {
+ %s = getelementptr i32, i32* %p, i32 6
+ %t = load i32, i32* %s
+ ret i32 %t
+}
+
; Same as above but with i64.
; CHECK-LABEL: load_i64_with_folded_offset:
@@ -45,6 +79,28 @@ define i64 @load_i64_with_folded_offset(i64* %p) {
; Same as above but with i64.
+; CHECK-LABEL: load_i64_with_folded_gep_offset:
+; CHECK: i64.load $push0=, 24($0){{$}}
+define i64 @load_i64_with_folded_gep_offset(i64* %p) {
+ %s = getelementptr inbounds i64, i64* %p, i32 3
+ %t = load i64, i64* %s
+ ret i64 %t
+}
+
+; Same as above but with i64.
+
+; CHECK-LABEL: load_i64_with_unfolded_gep_negative_offset:
+; CHECK: i32.const $push0=, -24{{$}}
+; CHECK: i32.add $push1=, $0, $pop0{{$}}
+; CHECK: i64.load $push2=, 0($pop1){{$}}
+define i64 @load_i64_with_unfolded_gep_negative_offset(i64* %p) {
+ %s = getelementptr inbounds i64, i64* %p, i32 -3
+ %t = load i64, i64* %s
+ ret i64 %t
+}
+
+; Same as above but with i64.
+
; CHECK-LABEL: load_i64_with_unfolded_offset:
; CHECK: i32.const $push0=, 24{{$}}
; CHECK: i32.add $push1=, $0, $pop0{{$}}
@@ -57,6 +113,18 @@ define i64 @load_i64_with_unfolded_offset(i64* %p) {
ret i64 %t
}
+; Same as above but with i64.
+
+; CHECK-LABEL: load_i64_with_unfolded_gep_offset:
+; CHECK: i32.const $push0=, 24{{$}}
+; CHECK: i32.add $push1=, $0, $pop0{{$}}
+; CHECK: i64.load $push2=, 0($pop1){{$}}
+define i64 @load_i64_with_unfolded_gep_offset(i64* %p) {
+ %s = getelementptr i64, i64* %p, i32 3
+ %t = load i64, i64* %s
+ ret i64 %t
+}
+
; Same as above but with store.
; CHECK-LABEL: store_i32_with_folded_offset:
@@ -71,6 +139,28 @@ define void @store_i32_with_folded_offset(i32* %p) {
; Same as above but with store.
+; CHECK-LABEL: store_i32_with_folded_gep_offset:
+; CHECK: i32.store $discard=, 24($0), $pop0{{$}}
+define void @store_i32_with_folded_gep_offset(i32* %p) {
+ %s = getelementptr inbounds i32, i32* %p, i32 6
+ store i32 0, i32* %s
+ ret void
+}
+
+; Same as above but with store.
+
+; CHECK-LABEL: store_i32_with_unfolded_gep_negative_offset:
+; CHECK: i32.const $push0=, -24{{$}}
+; CHECK: i32.add $push1=, $0, $pop0{{$}}
+; CHECK: i32.store $discard=, 0($pop1), $pop2{{$}}
+define void @store_i32_with_unfolded_gep_negative_offset(i32* %p) {
+ %s = getelementptr inbounds i32, i32* %p, i32 -6
+ store i32 0, i32* %s
+ ret void
+}
+
+; Same as above but with store.
+
; CHECK-LABEL: store_i32_with_unfolded_offset:
; CHECK: i32.const $push0=, 24{{$}}
; CHECK: i32.add $push1=, $0, $pop0{{$}}
@@ -83,6 +173,18 @@ define void @store_i32_with_unfolded_offset(i32* %p) {
ret void
}
+; Same as above but with store.
+
+; CHECK-LABEL: store_i32_with_unfolded_gep_offset:
+; CHECK: i32.const $push0=, 24{{$}}
+; CHECK: i32.add $push1=, $0, $pop0{{$}}
+; CHECK: i32.store $discard=, 0($pop1), $pop2{{$}}
+define void @store_i32_with_unfolded_gep_offset(i32* %p) {
+ %s = getelementptr i32, i32* %p, i32 6
+ store i32 0, i32* %s
+ ret void
+}
+
; Same as above but with store with i64.
; CHECK-LABEL: store_i64_with_folded_offset:
@@ -97,6 +199,28 @@ define void @store_i64_with_folded_offset(i64* %p) {
; Same as above but with store with i64.
+; CHECK-LABEL: store_i64_with_folded_gep_offset:
+; CHECK: i64.store $discard=, 24($0), $pop0{{$}}
+define void @store_i64_with_folded_gep_offset(i64* %p) {
+ %s = getelementptr inbounds i64, i64* %p, i32 3
+ store i64 0, i64* %s
+ ret void
+}
+
+; Same as above but with store with i64.
+
+; CHECK-LABEL: store_i64_with_unfolded_gep_negative_offset:
+; CHECK: i32.const $push0=, -24{{$}}
+; CHECK: i32.add $push1=, $0, $pop0{{$}}
+; CHECK: i64.store $discard=, 0($pop1), $pop2{{$}}
+define void @store_i64_with_unfolded_gep_negative_offset(i64* %p) {
+ %s = getelementptr inbounds i64, i64* %p, i32 -3
+ store i64 0, i64* %s
+ ret void
+}
+
+; Same as above but with store with i64.
+
; CHECK-LABEL: store_i64_with_unfolded_offset:
; CHECK: i32.const $push0=, 24{{$}}
; CHECK: i32.add $push1=, $0, $pop0{{$}}
@@ -109,6 +233,18 @@ define void @store_i64_with_unfolded_offset(i64* %p) {
ret void
}
+; Same as above but with store with i64.
+
+; CHECK-LABEL: store_i64_with_unfolded_gep_offset:
+; CHECK: i32.const $push0=, 24{{$}}
+; CHECK: i32.add $push1=, $0, $pop0{{$}}
+; CHECK: i64.store $discard=, 0($pop1), $pop2{{$}}
+define void @store_i64_with_unfolded_gep_offset(i64* %p) {
+ %s = getelementptr i64, i64* %p, i32 3
+ store i64 0, i64* %s
+ ret void
+}
+
; When loading from a fixed address, materialize a zero.
; CHECK-LABEL: load_i32_from_numeric_address
@@ -159,6 +295,17 @@ define i32 @load_i8_s_with_folded_offset(i8* %p) {
ret i32 %u
}
+; Fold a gep offset into a sign-extending load.
+
+; CHECK-LABEL: load_i8_s_with_folded_gep_offset:
+; CHECK: i32.load8_s $push0=, 24($0){{$}}
+define i32 @load_i8_s_with_folded_gep_offset(i8* %p) {
+ %s = getelementptr inbounds i8, i8* %p, i32 24
+ %t = load i8, i8* %s
+ %u = sext i8 %t to i32
+ ret i32 %u
+}
+
; Fold an offset into a zero-extending load.
; CHECK-LABEL: load_i8_u_with_folded_offset:
@@ -172,6 +319,17 @@ define i32 @load_i8_u_with_folded_offset(i8* %p) {
ret i32 %u
}
+; Fold a gep offset into a zero-extending load.
+
+; CHECK-LABEL: load_i8_u_with_folded_gep_offset:
+; CHECK: i32.load8_u $push0=, 24($0){{$}}
+define i32 @load_i8_u_with_folded_gep_offset(i8* %p) {
+ %s = getelementptr inbounds i8, i8* %p, i32 24
+ %t = load i8, i8* %s
+ %u = zext i8 %t to i32
+ ret i32 %u
+}
+
; Fold an offset into a truncating store.
; CHECK-LABEL: store_i8_with_folded_offset:
@@ -183,3 +341,43 @@ define void @store_i8_with_folded_offset(i8* %p) {
store i8 0, i8* %s
ret void
}
+
+; Fold a gep offset into a truncating store.
+
+; CHECK-LABEL: store_i8_with_folded_gep_offset:
+; CHECK: i32.store8 $discard=, 24($0), $pop0{{$}}
+define void @store_i8_with_folded_gep_offset(i8* %p) {
+ %s = getelementptr inbounds i8, i8* %p, i32 24
+ store i8 0, i8* %s
+ ret void
+}
+
+; Fold the offsets when lowering aggregate loads and stores.
+
+; CHECK-LABEL: aggregate_load_store:
+; CHECK: i32.load $2=, 0($0){{$}}
+; CHECK: i32.load $3=, 4($0){{$}}
+; CHECK: i32.load $4=, 8($0){{$}}
+; CHECK: i32.load $push0=, 12($0){{$}}
+; CHECK: i32.store $discard=, 12($1), $pop0{{$}}
+; CHECK: i32.store $discard=, 8($1), $4{{$}}
+; CHECK: i32.store $discard=, 4($1), $3{{$}}
+; CHECK: i32.store $discard=, 0($1), $2{{$}}
+define void @aggregate_load_store({i32,i32,i32,i32}* %p, {i32,i32,i32,i32}* %q) {
+ ; volatile so that things stay in order for the tests above
+ %t = load volatile {i32,i32,i32,i32}, {i32, i32,i32,i32}* %p
+ store volatile {i32,i32,i32,i32} %t, {i32, i32,i32,i32}* %q
+ ret void
+}
+
+; Fold the offsets when lowering aggregate return values.
+
+; CHECK-LABEL: aggregate_return:
+; CHECK: i32.const $push0=, 0{{$}}
+; CHECK: i32.store $push1=, 12($0), $pop0{{$}}
+; CHECK: i32.store $push2=, 8($0), $pop1{{$}}
+; CHECK: i32.store $push3=, 4($0), $pop2{{$}}
+; CHECK: i32.store $discard=, 0($0), $pop3{{$}}
+define {i32,i32,i32,i32} @aggregate_return() {
+ ret {i32,i32,i32,i32} zeroinitializer
+}
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