[llvm] r302937 - [PPC] Move the combine "a << (b % (sizeof(a) * 8)) -> (PPCshl a, b)" to the backend. NFC.
Tim Shen via llvm-commits
llvm-commits at lists.llvm.org
Fri May 12 12:25:38 PDT 2017
Author: timshen
Date: Fri May 12 14:25:37 2017
New Revision: 302937
URL: http://llvm.org/viewvc/llvm-project?rev=302937&view=rev
Log:
[PPC] Move the combine "a << (b % (sizeof(a) * 8)) -> (PPCshl a, b)" to the backend. NFC.
Summary:
Eli pointed out that it's unsafe to combine the shifts to ISD::SHL etc.,
because those are not defined for b > sizeof(a) * 8, even after some of
the combiners run.
However, PPCISD::SHL defines that behavior (as the instructions themselves).
Move the combination to the backend.
The tests in shift_mask.ll still pass.
Reviewers: echristo, hfinkel, efriedma, iteratee
Subscribers: nemanjai, llvm-commits
Differential Revision: https://reviews.llvm.org/D33076
Modified:
llvm/trunk/include/llvm/Target/TargetLowering.h
llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h
llvm/trunk/lib/Target/PowerPC/PPCInstrAltivec.td
Modified: llvm/trunk/include/llvm/Target/TargetLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Target/TargetLowering.h?rev=302937&r1=302936&r2=302937&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Target/TargetLowering.h (original)
+++ llvm/trunk/include/llvm/Target/TargetLowering.h Fri May 12 14:25:37 2017
@@ -2063,14 +2063,6 @@ public:
return false;
}
- // Return true if the instruction that performs a << b actually performs
- // a << (b % (sizeof(a) * 8)).
- virtual bool supportsModuloShift(ISD::NodeType Inst, EVT ReturnType) const {
- assert((Inst == ISD::SHL || Inst == ISD::SRA || Inst == ISD::SRL) &&
- "Expect a shift instruction");
- return false;
- }
-
//===--------------------------------------------------------------------===//
// Runtime Library hooks
//
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=302937&r1=302936&r2=302937&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Fri May 12 14:25:37 2017
@@ -5313,17 +5313,6 @@ SDValue DAGCombiner::visitSHL(SDNode *N)
}
}
- // If the target supports masking y in (shl, y),
- // fold (shl x, (and y, ((1 << numbits(x)) - 1))) -> (shl x, y)
- if (TLI.isOperationLegal(ISD::SHL, VT) &&
- TLI.supportsModuloShift(ISD::SHL, VT) && N1->getOpcode() == ISD::AND) {
- if (ConstantSDNode *Mask = isConstOrConstSplat(N1->getOperand(1))) {
- if (Mask->getZExtValue() == OpSizeInBits - 1) {
- return DAG.getNode(ISD::SHL, SDLoc(N), VT, N0, N1->getOperand(0));
- }
- }
- }
-
ConstantSDNode *N1C = isConstOrConstSplat(N1);
// fold (shl c1, c2) -> c1<<c2
@@ -5522,17 +5511,6 @@ SDValue DAGCombiner::visitSRA(SDNode *N)
EVT VT = N0.getValueType();
unsigned OpSizeInBits = VT.getScalarSizeInBits();
- // If the target supports masking y in (sra, y),
- // fold (sra x, (and y, ((1 << numbits(x)) - 1))) -> (sra x, y)
- if (TLI.isOperationLegal(ISD::SRA, VT) &&
- TLI.supportsModuloShift(ISD::SRA, VT) && N1->getOpcode() == ISD::AND) {
- if (ConstantSDNode *Mask = isConstOrConstSplat(N1->getOperand(1))) {
- if (Mask->getZExtValue() == OpSizeInBits - 1) {
- return DAG.getNode(ISD::SRA, SDLoc(N), VT, N0, N1->getOperand(0));
- }
- }
- }
-
// Arithmetic shifting an all-sign-bit value is a no-op.
// fold (sra 0, x) -> 0
// fold (sra -1, x) -> -1
@@ -5687,17 +5665,6 @@ SDValue DAGCombiner::visitSRL(SDNode *N)
EVT VT = N0.getValueType();
unsigned OpSizeInBits = VT.getScalarSizeInBits();
- // If the target supports masking y in (srl, y),
- // fold (srl x, (and y, ((1 << numbits(x)) - 1))) -> (srl x, y)
- if (TLI.isOperationLegal(ISD::SRL, VT) &&
- TLI.supportsModuloShift(ISD::SRL, VT) && N1->getOpcode() == ISD::AND) {
- if (ConstantSDNode *Mask = isConstOrConstSplat(N1->getOperand(1))) {
- if (Mask->getZExtValue() == OpSizeInBits - 1) {
- return DAG.getNode(ISD::SRL, SDLoc(N), VT, N0, N1->getOperand(0));
- }
- }
- }
-
// fold vector ops
if (VT.isVector())
if (SDValue FoldedVOp = SimplifyVBinOp(N))
Modified: llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp?rev=302937&r1=302936&r2=302937&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCISelLowering.cpp Fri May 12 14:25:37 2017
@@ -923,6 +923,9 @@ PPCTargetLowering::PPCTargetLowering(con
setStackPointerRegisterToSaveRestore(isPPC64 ? PPC::X1 : PPC::R1);
// We have target-specific dag combine patterns for the following nodes:
+ setTargetDAGCombine(ISD::SHL);
+ setTargetDAGCombine(ISD::SRA);
+ setTargetDAGCombine(ISD::SRL);
setTargetDAGCombine(ISD::SINT_TO_FP);
setTargetDAGCombine(ISD::BUILD_VECTOR);
if (Subtarget.hasFPCVT())
@@ -11312,6 +11315,12 @@ SDValue PPCTargetLowering::PerformDAGCom
SDLoc dl(N);
switch (N->getOpcode()) {
default: break;
+ case ISD::SHL:
+ return combineSHL(N, DCI);
+ case ISD::SRA:
+ return combineSRA(N, DCI);
+ case ISD::SRL:
+ return combineSRL(N, DCI);
case PPCISD::SHL:
if (isNullConstant(N->getOperand(0))) // 0 << V -> 0.
return N->getOperand(0);
@@ -12944,3 +12953,58 @@ bool PPCTargetLowering::isFPImmLegal(con
return Imm.isPosZero();
}
}
+
+// For vector shift operation op, fold
+// (op x, (and y, ((1 << numbits(x)) - 1))) -> (target op x, y)
+static SDValue stripModuloOnShift(const TargetLowering &TLI, SDNode *N,
+ SelectionDAG &DAG) {
+ SDValue N0 = N->getOperand(0);
+ SDValue N1 = N->getOperand(1);
+ EVT VT = N0.getValueType();
+ unsigned OpSizeInBits = VT.getScalarSizeInBits();
+ unsigned Opcode = N->getOpcode();
+ unsigned TargetOpcode;
+
+ switch (Opcode) {
+ default:
+ llvm_unreachable("Unexpected shift operation");
+ case ISD::SHL:
+ TargetOpcode = PPCISD::SHL;
+ break;
+ case ISD::SRL:
+ TargetOpcode = PPCISD::SRL;
+ break;
+ case ISD::SRA:
+ TargetOpcode = PPCISD::SRA;
+ break;
+ }
+
+ if (VT.isVector() && TLI.isOperationLegal(Opcode, VT) &&
+ N1->getOpcode() == ISD::AND)
+ if (ConstantSDNode *Mask = isConstOrConstSplat(N1->getOperand(1)))
+ if (Mask->getZExtValue() == OpSizeInBits - 1)
+ return DAG.getNode(TargetOpcode, SDLoc(N), VT, N0, N1->getOperand(0));
+
+ return SDValue();
+}
+
+SDValue PPCTargetLowering::combineSHL(SDNode *N, DAGCombinerInfo &DCI) const {
+ if (auto Value = stripModuloOnShift(*this, N, DCI.DAG))
+ return Value;
+
+ return SDValue();
+}
+
+SDValue PPCTargetLowering::combineSRA(SDNode *N, DAGCombinerInfo &DCI) const {
+ if (auto Value = stripModuloOnShift(*this, N, DCI.DAG))
+ return Value;
+
+ return SDValue();
+}
+
+SDValue PPCTargetLowering::combineSRL(SDNode *N, DAGCombinerInfo &DCI) const {
+ if (auto Value = stripModuloOnShift(*this, N, DCI.DAG))
+ return Value;
+
+ return SDValue();
+}
Modified: llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h?rev=302937&r1=302936&r2=302937&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCISelLowering.h Fri May 12 14:25:37 2017
@@ -117,9 +117,13 @@ namespace llvm {
/// at function entry, used for PIC code.
GlobalBaseReg,
- /// These nodes represent the 32-bit PPC shifts that operate on 6-bit
- /// shift amounts. These nodes are generated by the multi-precision shift
- /// code.
+ /// These nodes represent PPC shifts.
+ ///
+ /// For scalar types, only the last `n + 1` bits of the shift amounts
+ /// are used, where n is log2(sizeof(element) * 8). See sld/slw, etc.
+ /// for exact behaviors.
+ ///
+ /// For vector types, only the last n bits are used. See vsld.
SRL, SRA, SHL,
/// The combination of sra[wd]i and addze used to implemented signed
@@ -999,6 +1003,9 @@ namespace llvm {
SDValue DAGCombineBuildVector(SDNode *N, DAGCombinerInfo &DCI) const;
SDValue DAGCombineTruncBoolExt(SDNode *N, DAGCombinerInfo &DCI) const;
SDValue combineFPToIntToFP(SDNode *N, DAGCombinerInfo &DCI) const;
+ SDValue combineSHL(SDNode *N, DAGCombinerInfo &DCI) const;
+ SDValue combineSRA(SDNode *N, DAGCombinerInfo &DCI) const;
+ SDValue combineSRL(SDNode *N, DAGCombinerInfo &DCI) const;
/// ConvertSETCCToSubtract - looks at SETCC that compares ints. It replaces
/// SETCC with integer subtraction when (1) there is a legal way of doing it
@@ -1017,14 +1024,6 @@ namespace llvm {
SDValue
combineElementTruncationToVectorTruncation(SDNode *N,
DAGCombinerInfo &DCI) const;
-
- bool supportsModuloShift(ISD::NodeType Inst,
- EVT ReturnType) const override {
- assert((Inst == ISD::SHL || Inst == ISD::SRA || Inst == ISD::SRL) &&
- "Expect a shift instruction");
- assert(isOperationLegal(Inst, ReturnType));
- return ReturnType.isVector();
- }
};
namespace PPC {
Modified: llvm/trunk/lib/Target/PowerPC/PPCInstrAltivec.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/PowerPC/PPCInstrAltivec.td?rev=302937&r1=302936&r2=302937&view=diff
==============================================================================
--- llvm/trunk/lib/Target/PowerPC/PPCInstrAltivec.td (original)
+++ llvm/trunk/lib/Target/PowerPC/PPCInstrAltivec.td Fri May 12 14:25:37 2017
@@ -987,6 +987,12 @@ def : Pat<(v8i16 (shl v8i16:$vA, v8i16:$
(v8i16 (VSLH $vA, $vB))>;
def : Pat<(v4i32 (shl v4i32:$vA, v4i32:$vB)),
(v4i32 (VSLW $vA, $vB))>;
+def : Pat<(v16i8 (PPCshl v16i8:$vA, v16i8:$vB)),
+ (v16i8 (VSLB $vA, $vB))>;
+def : Pat<(v8i16 (PPCshl v8i16:$vA, v8i16:$vB)),
+ (v8i16 (VSLH $vA, $vB))>;
+def : Pat<(v4i32 (PPCshl v4i32:$vA, v4i32:$vB)),
+ (v4i32 (VSLW $vA, $vB))>;
def : Pat<(v16i8 (srl v16i8:$vA, v16i8:$vB)),
(v16i8 (VSRB $vA, $vB))>;
@@ -994,6 +1000,12 @@ def : Pat<(v8i16 (srl v8i16:$vA, v8i16:$
(v8i16 (VSRH $vA, $vB))>;
def : Pat<(v4i32 (srl v4i32:$vA, v4i32:$vB)),
(v4i32 (VSRW $vA, $vB))>;
+def : Pat<(v16i8 (PPCsrl v16i8:$vA, v16i8:$vB)),
+ (v16i8 (VSRB $vA, $vB))>;
+def : Pat<(v8i16 (PPCsrl v8i16:$vA, v8i16:$vB)),
+ (v8i16 (VSRH $vA, $vB))>;
+def : Pat<(v4i32 (PPCsrl v4i32:$vA, v4i32:$vB)),
+ (v4i32 (VSRW $vA, $vB))>;
def : Pat<(v16i8 (sra v16i8:$vA, v16i8:$vB)),
(v16i8 (VSRAB $vA, $vB))>;
@@ -1001,6 +1013,12 @@ def : Pat<(v8i16 (sra v8i16:$vA, v8i16:$
(v8i16 (VSRAH $vA, $vB))>;
def : Pat<(v4i32 (sra v4i32:$vA, v4i32:$vB)),
(v4i32 (VSRAW $vA, $vB))>;
+def : Pat<(v16i8 (PPCsra v16i8:$vA, v16i8:$vB)),
+ (v16i8 (VSRAB $vA, $vB))>;
+def : Pat<(v8i16 (PPCsra v8i16:$vA, v8i16:$vB)),
+ (v8i16 (VSRAH $vA, $vB))>;
+def : Pat<(v4i32 (PPCsra v4i32:$vA, v4i32:$vB)),
+ (v4i32 (VSRAW $vA, $vB))>;
// Float to integer and integer to float conversions
def : Pat<(v4i32 (fp_to_sint v4f32:$vA)),
@@ -1072,14 +1090,24 @@ def:Pat<(vmrgow_swapped_shuffle v16i8:$v
// Vector shifts
def VRLD : VX1_Int_Ty<196, "vrld", int_ppc_altivec_vrld, v2i64>;
def VSLD : VXForm_1<1476, (outs vrrc:$vD), (ins vrrc:$vA, vrrc:$vB),
- "vsld $vD, $vA, $vB", IIC_VecGeneral,
- [(set v2i64:$vD, (shl v2i64:$vA, v2i64:$vB))]>;
+ "vsld $vD, $vA, $vB", IIC_VecGeneral, []>;
def VSRD : VXForm_1<1732, (outs vrrc:$vD), (ins vrrc:$vA, vrrc:$vB),
- "vsrd $vD, $vA, $vB", IIC_VecGeneral,
- [(set v2i64:$vD, (srl v2i64:$vA, v2i64:$vB))]>;
+ "vsrd $vD, $vA, $vB", IIC_VecGeneral, []>;
def VSRAD : VXForm_1<964, (outs vrrc:$vD), (ins vrrc:$vA, vrrc:$vB),
- "vsrad $vD, $vA, $vB", IIC_VecGeneral,
- [(set v2i64:$vD, (sra v2i64:$vA, v2i64:$vB))]>;
+ "vsrad $vD, $vA, $vB", IIC_VecGeneral, []>;
+
+def : Pat<(v2i64 (shl v2i64:$vA, v2i64:$vB)),
+ (v2i64 (VSLD $vA, $vB))>;
+def : Pat<(v2i64 (PPCshl v2i64:$vA, v2i64:$vB)),
+ (v2i64 (VSLD $vA, $vB))>;
+def : Pat<(v2i64 (srl v2i64:$vA, v2i64:$vB)),
+ (v2i64 (VSRD $vA, $vB))>;
+def : Pat<(v2i64 (PPCsrl v2i64:$vA, v2i64:$vB)),
+ (v2i64 (VSRD $vA, $vB))>;
+def : Pat<(v2i64 (sra v2i64:$vA, v2i64:$vB)),
+ (v2i64 (VSRAD $vA, $vB))>;
+def : Pat<(v2i64 (PPCsra v2i64:$vA, v2i64:$vB)),
+ (v2i64 (VSRAD $vA, $vB))>;
// Vector Integer Arithmetic Instructions
let isCommutable = 1 in {
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