[llvm] r252878 - [SDAG] Introduce a new BITREVERSE node along with a corresponding LLVM intrinsic
James Molloy via llvm-commits
llvm-commits at lists.llvm.org
Thu Nov 12 04:29:10 PST 2015
Author: jamesm
Date: Thu Nov 12 06:29:09 2015
New Revision: 252878
URL: http://llvm.org/viewvc/llvm-project?rev=252878&view=rev
Log:
[SDAG] Introduce a new BITREVERSE node along with a corresponding LLVM intrinsic
Several backends have instructions to reverse the order of bits in an integer. Conceptually matching such patterns is similar to @llvm.bswap, and it was mentioned in http://reviews.llvm.org/D14234 that it would be best if these patterns were matched in InstCombine instead of reimplemented in every different target.
This patch introduces an intrinsic @llvm.bitreverse.i* that operates similarly to @llvm.bswap. For plumbing purposes there is also a new ISD node ISD::BITREVERSE, with simple expansion and promotion support.
The intention is that InstCombine's BSWAP detection logic will be extended to support BITREVERSE too, and @llvm.bitreverse intrinsics emitted (if the backend supports lowering it efficiently).
Added:
llvm/trunk/test/CodeGen/AArch64/bitreverse.ll
llvm/trunk/test/CodeGen/PowerPC/bitreverse.ll
llvm/trunk/test/CodeGen/X86/bitreverse.ll
Modified:
llvm/trunk/docs/LangRef.rst
llvm/trunk/include/llvm/CodeGen/ISDOpcodes.h
llvm/trunk/include/llvm/IR/Intrinsics.td
llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp
Modified: llvm/trunk/docs/LangRef.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.rst?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/docs/LangRef.rst (original)
+++ llvm/trunk/docs/LangRef.rst Thu Nov 12 06:29:09 2015
@@ -10417,6 +10417,34 @@ Bit Manipulation Intrinsics
LLVM provides intrinsics for a few important bit manipulation
operations. These allow efficient code generation for some algorithms.
+'``llvm.bitreverse.*``' Intrinsics
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+Syntax:
+"""""""
+
+This is an overloaded intrinsic function. You can use bitreverse on any
+integer type.
+
+::
+
+ declare i16 @llvm.bitreverse.i16(i16 <id>)
+ declare i32 @llvm.bitreverse.i32(i32 <id>)
+ declare i64 @llvm.bitreverse.i64(i64 <id>)
+
+Overview:
+"""""""""
+
+The '``llvm.bitreverse``' family of intrinsics is used to reverse the
+bitpattern of an integer value; for example ``0b1234567`` becomes
+``0b7654321``.
+
+Semantics:
+""""""""""
+
+The ``llvm.bitreverse.iN`` intrinsic returns an i16 value that has bit
+``M`` in the input moved to bit ``N-M`` in the output.
+
'``llvm.bswap.*``' Intrinsics
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Modified: llvm/trunk/include/llvm/CodeGen/ISDOpcodes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/ISDOpcodes.h?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/ISDOpcodes.h (original)
+++ llvm/trunk/include/llvm/CodeGen/ISDOpcodes.h Thu Nov 12 06:29:09 2015
@@ -336,7 +336,7 @@ namespace ISD {
SHL, SRA, SRL, ROTL, ROTR,
/// Byte Swap and Counting operators.
- BSWAP, CTTZ, CTLZ, CTPOP,
+ BSWAP, CTTZ, CTLZ, CTPOP, BITREVERSE,
/// [SU]ABSDIFF - Signed/Unsigned absolute difference of two input integer
/// vector. These nodes are generated from llvm.*absdiff* intrinsics.
Modified: llvm/trunk/include/llvm/IR/Intrinsics.td
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/IR/Intrinsics.td?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/include/llvm/IR/Intrinsics.td (original)
+++ llvm/trunk/include/llvm/IR/Intrinsics.td Thu Nov 12 06:29:09 2015
@@ -400,6 +400,7 @@ let Properties = [IntrNoMem] in {
def int_ctpop: Intrinsic<[llvm_anyint_ty], [LLVMMatchType<0>]>;
def int_ctlz : Intrinsic<[llvm_anyint_ty], [LLVMMatchType<0>, llvm_i1_ty]>;
def int_cttz : Intrinsic<[llvm_anyint_ty], [LLVMMatchType<0>, llvm_i1_ty]>;
+ def int_bitreverse : Intrinsic<[llvm_anyint_ty], [LLVMMatchType<0>]>;
}
//===------------------------ Debugger Intrinsics -------------------------===//
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp Thu Nov 12 06:29:09 2015
@@ -145,6 +145,7 @@ private:
SDValue PromoteLegalFP_TO_INT(SDValue LegalOp, EVT DestVT, bool isSigned,
SDLoc dl);
+ SDValue ExpandBITREVERSE(SDValue Op, SDLoc dl);
SDValue ExpandBSWAP(SDValue Op, SDLoc dl);
SDValue ExpandBitCount(unsigned Opc, SDValue Op, SDLoc dl);
@@ -2775,6 +2776,29 @@ SDValue SelectionDAGLegalize::PromoteLeg
return DAG.getNode(ISD::TRUNCATE, dl, DestVT, Operation);
}
+/// Open code the operations for BITREVERSE.
+SDValue SelectionDAGLegalize::ExpandBITREVERSE(SDValue Op, SDLoc dl) {
+ EVT VT = Op.getValueType();
+ EVT SHVT = TLI.getShiftAmountTy(VT, DAG.getDataLayout());
+ unsigned Sz = VT.getSizeInBits();
+
+ SDValue Tmp, Tmp2;
+ Tmp = DAG.getConstant(0, dl, VT);
+ for (unsigned I = 0, J = Sz-1; I < Sz; ++I, --J) {
+ if (I < J)
+ Tmp2 =
+ DAG.getNode(ISD::SHL, dl, VT, Op, DAG.getConstant(J - I, dl, SHVT));
+ else
+ Tmp2 =
+ DAG.getNode(ISD::SRL, dl, VT, Op, DAG.getConstant(I - J, dl, SHVT));
+ Tmp2 =
+ DAG.getNode(ISD::AND, dl, VT, Tmp2, DAG.getConstant(1U << J, dl, VT));
+ Tmp = DAG.getNode(ISD::OR, dl, VT, Tmp, Tmp2);
+ }
+
+ return Tmp;
+}
+
/// Open code the operations for BSWAP of the specified operation.
SDValue SelectionDAGLegalize::ExpandBSWAP(SDValue Op, SDLoc dl) {
EVT VT = Op.getValueType();
@@ -2941,6 +2965,9 @@ bool SelectionDAGLegalize::ExpandNode(SD
Tmp1 = ExpandBitCount(Node->getOpcode(), Node->getOperand(0), dl);
Results.push_back(Tmp1);
break;
+ case ISD::BITREVERSE:
+ Results.push_back(ExpandBITREVERSE(Node->getOperand(0), dl));
+ break;
case ISD::BSWAP:
Results.push_back(ExpandBSWAP(Node->getOperand(0), dl));
break;
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp Thu Nov 12 06:29:09 2015
@@ -53,6 +53,7 @@ void DAGTypeLegalizer::PromoteIntegerRes
case ISD::AssertSext: Res = PromoteIntRes_AssertSext(N); break;
case ISD::AssertZext: Res = PromoteIntRes_AssertZext(N); break;
case ISD::BITCAST: Res = PromoteIntRes_BITCAST(N); break;
+ case ISD::BITREVERSE: Res = PromoteIntRes_BITREVERSE(N); break;
case ISD::BSWAP: Res = PromoteIntRes_BSWAP(N); break;
case ISD::BUILD_PAIR: Res = PromoteIntRes_BUILD_PAIR(N); break;
case ISD::Constant: Res = PromoteIntRes_Constant(N); break;
@@ -320,6 +321,19 @@ SDValue DAGTypeLegalizer::PromoteIntRes_
TLI.getShiftAmountTy(NVT, DAG.getDataLayout())));
}
+SDValue DAGTypeLegalizer::PromoteIntRes_BITREVERSE(SDNode *N) {
+ SDValue Op = GetPromotedInteger(N->getOperand(0));
+ EVT OVT = N->getValueType(0);
+ EVT NVT = Op.getValueType();
+ SDLoc dl(N);
+
+ unsigned DiffBits = NVT.getScalarSizeInBits() - OVT.getScalarSizeInBits();
+ return DAG.getNode(
+ ISD::SRL, dl, NVT, DAG.getNode(ISD::BITREVERSE, dl, NVT, Op),
+ DAG.getConstant(DiffBits, dl,
+ TLI.getShiftAmountTy(NVT, DAG.getDataLayout())));
+}
+
SDValue DAGTypeLegalizer::PromoteIntRes_BUILD_PAIR(SDNode *N) {
// The pair element type may be legal, or may not promote to the same type as
// the result, for example i14 = BUILD_PAIR (i7, i7). Handle all cases.
@@ -1263,6 +1277,7 @@ void DAGTypeLegalizer::ExpandIntegerResu
case ISD::ANY_EXTEND: ExpandIntRes_ANY_EXTEND(N, Lo, Hi); break;
case ISD::AssertSext: ExpandIntRes_AssertSext(N, Lo, Hi); break;
case ISD::AssertZext: ExpandIntRes_AssertZext(N, Lo, Hi); break;
+ case ISD::BITREVERSE: ExpandIntRes_BITREVERSE(N, Lo, Hi); break;
case ISD::BSWAP: ExpandIntRes_BSWAP(N, Lo, Hi); break;
case ISD::Constant: ExpandIntRes_Constant(N, Lo, Hi); break;
case ISD::CTLZ_ZERO_UNDEF:
@@ -1833,6 +1848,14 @@ void DAGTypeLegalizer::ExpandIntRes_Asse
}
}
+void DAGTypeLegalizer::ExpandIntRes_BITREVERSE(SDNode *N,
+ SDValue &Lo, SDValue &Hi) {
+ SDLoc dl(N);
+ GetExpandedInteger(N->getOperand(0), Hi, Lo); // Note swapped operands.
+ Lo = DAG.getNode(ISD::BITREVERSE, dl, Lo.getValueType(), Lo);
+ Hi = DAG.getNode(ISD::BITREVERSE, dl, Hi.getValueType(), Hi);
+}
+
void DAGTypeLegalizer::ExpandIntRes_BSWAP(SDNode *N,
SDValue &Lo, SDValue &Hi) {
SDLoc dl(N);
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h Thu Nov 12 06:29:09 2015
@@ -234,6 +234,7 @@ private:
SDValue PromoteIntRes_CONCAT_VECTORS(SDNode *N);
SDValue PromoteIntRes_BITCAST(SDNode *N);
SDValue PromoteIntRes_BSWAP(SDNode *N);
+ SDValue PromoteIntRes_BITREVERSE(SDNode *N);
SDValue PromoteIntRes_BUILD_PAIR(SDNode *N);
SDValue PromoteIntRes_Constant(SDNode *N);
SDValue PromoteIntRes_CONVERT_RNDSAT(SDNode *N);
@@ -330,6 +331,7 @@ private:
void ExpandIntRes_ADDSUB (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_ADDSUBC (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_ADDSUBE (SDNode *N, SDValue &Lo, SDValue &Hi);
+ void ExpandIntRes_BITREVERSE (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_BSWAP (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_MUL (SDNode *N, SDValue &Lo, SDValue &Hi);
void ExpandIntRes_SDIV (SDNode *N, SDValue &Lo, SDValue &Hi);
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp Thu Nov 12 06:29:09 2015
@@ -67,6 +67,7 @@ void DAGTypeLegalizer::ScalarizeVectorRe
case ISD::UNDEF: R = ScalarizeVecRes_UNDEF(N); break;
case ISD::VECTOR_SHUFFLE: R = ScalarizeVecRes_VECTOR_SHUFFLE(N); break;
case ISD::ANY_EXTEND:
+ case ISD::BITREVERSE:
case ISD::BSWAP:
case ISD::CTLZ:
case ISD::CTLZ_ZERO_UNDEF:
@@ -616,6 +617,7 @@ void DAGTypeLegalizer::SplitVectorResult
SplitVecRes_VECTOR_SHUFFLE(cast<ShuffleVectorSDNode>(N), Lo, Hi);
break;
+ case ISD::BITREVERSE:
case ISD::BSWAP:
case ISD::CONVERT_RNDSAT:
case ISD::CTLZ:
@@ -2027,6 +2029,7 @@ void DAGTypeLegalizer::WidenVectorResult
Res = WidenVecRes_Convert(N);
break;
+ case ISD::BITREVERSE:
case ISD::BSWAP:
case ISD::CTLZ:
case ISD::CTPOP:
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp Thu Nov 12 06:29:09 2015
@@ -4872,6 +4872,11 @@ SelectionDAGBuilder::visitIntrinsicCall(
DAG.setRoot(Res.getValue(1));
return nullptr;
}
+ case Intrinsic::bitreverse:
+ setValue(&I, DAG.getNode(ISD::BITREVERSE, sdl,
+ getValue(I.getArgOperand(0)).getValueType(),
+ getValue(I.getArgOperand(0))));
+ return nullptr;
case Intrinsic::bswap:
setValue(&I, DAG.getNode(ISD::BSWAP, sdl,
getValue(I.getArgOperand(0)).getValueType(),
Modified: llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp Thu Nov 12 06:29:09 2015
@@ -311,13 +311,14 @@ std::string SDNode::getOperationName(con
case ISD::GC_TRANSITION_END: return "gc_transition.end";
// Bit manipulation
+ case ISD::BITREVERSE: return "bitreverse";
case ISD::BSWAP: return "bswap";
case ISD::CTPOP: return "ctpop";
case ISD::CTTZ: return "cttz";
case ISD::CTTZ_ZERO_UNDEF: return "cttz_zero_undef";
case ISD::CTLZ: return "ctlz";
case ISD::CTLZ_ZERO_UNDEF: return "ctlz_zero_undef";
-
+
// Trampolines
case ISD::INIT_TRAMPOLINE: return "init_trampoline";
case ISD::ADJUST_TRAMPOLINE: return "adjust_trampoline";
Modified: llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp?rev=252878&r1=252877&r2=252878&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp (original)
+++ llvm/trunk/lib/CodeGen/TargetLoweringBase.cpp Thu Nov 12 06:29:09 2015
@@ -828,7 +828,8 @@ void TargetLoweringBase::initActions() {
setOperationAction(ISD::UMULO, VT, Expand);
setOperationAction(ISD::UABSDIFF, VT, Expand);
setOperationAction(ISD::SABSDIFF, VT, Expand);
-
+ setOperationAction(ISD::BITREVERSE, VT, Expand);
+
// These library functions default to expand.
setOperationAction(ISD::FROUND, VT, Expand);
Added: llvm/trunk/test/CodeGen/AArch64/bitreverse.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/AArch64/bitreverse.ll?rev=252878&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/AArch64/bitreverse.ll (added)
+++ llvm/trunk/test/CodeGen/AArch64/bitreverse.ll Thu Nov 12 06:29:09 2015
@@ -0,0 +1,23 @@
+; RUN: llc -mtriple=aarch64-eabi %s -o - | FileCheck %s
+
+; These tests just check that the plumbing is in place for @llvm.bitreverse. The
+; actual output is massive at the moment as llvm.bitreverse is not yet legal.
+
+declare <2 x i16> @llvm.bitreverse.v2i16(<2 x i16>) readnone
+
+define <2 x i16> @f(<2 x i16> %a) {
+; CHECK-LABEL: f:
+; CHECK: ushr
+ %b = call <2 x i16> @llvm.bitreverse.v2i16(<2 x i16> %a)
+ ret <2 x i16> %b
+}
+
+declare i8 @llvm.bitreverse.i8(i8) readnone
+
+define i8 @g(i8 %a) {
+; CHECK-LABEL: g:
+; CHECK: lsl
+; CHECK: and
+ %b = call i8 @llvm.bitreverse.i8(i8 %a)
+ ret i8 %b
+}
Added: llvm/trunk/test/CodeGen/PowerPC/bitreverse.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/PowerPC/bitreverse.ll?rev=252878&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/PowerPC/bitreverse.ll (added)
+++ llvm/trunk/test/CodeGen/PowerPC/bitreverse.ll Thu Nov 12 06:29:09 2015
@@ -0,0 +1,23 @@
+; RUN: llc -march=ppc64 %s -o - | FileCheck %s
+
+; These tests just check that the plumbing is in place for @llvm.bitreverse. The
+; actual output is massive at the moment as llvm.bitreverse is not yet legal.
+
+declare <2 x i16> @llvm.bitreverse.v2i16(<2 x i16>) readnone
+
+define <2 x i16> @f(<2 x i16> %a) {
+; CHECK-LABEL: f:
+; CHECK: rlwinm
+ %b = call <2 x i16> @llvm.bitreverse.v2i16(<2 x i16> %a)
+ ret <2 x i16> %b
+}
+
+declare i8 @llvm.bitreverse.i8(i8) readnone
+
+define i8 @g(i8 %a) {
+; CHECK-LABEL: g:
+; CHECK: rlwinm
+; CHECK: rlwimi
+ %b = call i8 @llvm.bitreverse.i8(i8 %a)
+ ret i8 %b
+}
Added: llvm/trunk/test/CodeGen/X86/bitreverse.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/bitreverse.ll?rev=252878&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/bitreverse.ll (added)
+++ llvm/trunk/test/CodeGen/X86/bitreverse.ll Thu Nov 12 06:29:09 2015
@@ -0,0 +1,22 @@
+; RUN: llc -march=x86 %s -o - | FileCheck %s
+
+; These tests just check that the plumbing is in place for @llvm.bitreverse. The
+; actual output is massive at the moment as llvm.bitreverse is not yet legal.
+
+declare <2 x i16> @llvm.bitreverse.v2i16(<2 x i16>) readnone
+
+define <2 x i16> @f(<2 x i16> %a) {
+; CHECK-LABEL: f:
+; CHECK: shll
+ %b = call <2 x i16> @llvm.bitreverse.v2i16(<2 x i16> %a)
+ ret <2 x i16> %b
+}
+
+declare i8 @llvm.bitreverse.i8(i8) readnone
+
+define i8 @g(i8 %a) {
+; CHECK-LABEL: g:
+; CHECK: shlb
+ %b = call i8 @llvm.bitreverse.i8(i8 %a)
+ ret i8 %b
+}
More information about the llvm-commits
mailing list