[llvm] r241806 - Reapply fixed r241790: Fix shift legalization and lowering for big constants.

Pawel Bylica chfast at gmail.com
Thu Jul 9 07:58:04 PDT 2015


Author: chfast
Date: Thu Jul  9 09:58:04 2015
New Revision: 241806

URL: http://llvm.org/viewvc/llvm-project?rev=241806&view=rev
Log:
Reapply fixed r241790: Fix shift legalization and lowering for big constants.

Summary: If shift amount is a constant value > 64 bit it is handled incorrectly during type legalization and X86 lowering. This patch the type of shift amount argument in function DAGTypeLegalizer::ExpandShiftByConstant from unsigned to APInt.

Reviewers: nadav, majnemer, sanjoy, RKSimon

Subscribers: RKSimon, llvm-commits

Differential Revision: http://reviews.llvm.org/D10767

Added:
    llvm/trunk/test/CodeGen/X86/legalize-shl-vec.ll
Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
    llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp?rev=241806&r1=241805&r2=241806&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeIntegerTypes.cpp Thu Jul  9 09:58:04 2015
@@ -1358,9 +1358,9 @@ std::pair <SDValue, SDValue> DAGTypeLega
   return ExpandChainLibCall(LC, Node, false);
 }
 
-/// ExpandShiftByConstant - N is a shift by a value that needs to be expanded,
+/// N is a shift by a value that needs to be expanded,
 /// and the shift amount is a constant 'Amt'.  Expand the operation.
-void DAGTypeLegalizer::ExpandShiftByConstant(SDNode *N, unsigned Amt,
+void DAGTypeLegalizer::ExpandShiftByConstant(SDNode *N, const APInt &Amt,
                                              SDValue &Lo, SDValue &Hi) {
   SDLoc DL(N);
   // Expand the incoming operand to be shifted, so that we have its parts
@@ -1381,9 +1381,9 @@ void DAGTypeLegalizer::ExpandShiftByCons
   EVT ShTy = N->getOperand(1).getValueType();
 
   if (N->getOpcode() == ISD::SHL) {
-    if (Amt > VTBits) {
+    if (Amt.ugt(VTBits)) {
       Lo = Hi = DAG.getConstant(0, DL, NVT);
-    } else if (Amt > NVTBits) {
+    } else if (Amt.ugt(NVTBits)) {
       Lo = DAG.getConstant(0, DL, NVT);
       Hi = DAG.getNode(ISD::SHL, DL,
                        NVT, InL, DAG.getConstant(Amt - NVTBits, DL, ShTy));
@@ -1405,16 +1405,15 @@ void DAGTypeLegalizer::ExpandShiftByCons
                        DAG.getNode(ISD::SHL, DL, NVT, InH,
                                    DAG.getConstant(Amt, DL, ShTy)),
                        DAG.getNode(ISD::SRL, DL, NVT, InL,
-                                   DAG.getConstant(NVTBits - Amt, DL, ShTy)));
+                                   DAG.getConstant(-Amt + NVTBits, DL, ShTy)));
     }
     return;
   }
 
   if (N->getOpcode() == ISD::SRL) {
-    if (Amt > VTBits) {
-      Lo = DAG.getConstant(0, DL, NVT);
-      Hi = DAG.getConstant(0, DL, NVT);
-    } else if (Amt > NVTBits) {
+    if (Amt.ugt(VTBits)) {
+      Lo = Hi = DAG.getConstant(0, DL, NVT);
+    } else if (Amt.ugt(NVTBits)) {
       Lo = DAG.getNode(ISD::SRL, DL,
                        NVT, InH, DAG.getConstant(Amt - NVTBits, DL, ShTy));
       Hi = DAG.getConstant(0, DL, NVT);
@@ -1426,19 +1425,19 @@ void DAGTypeLegalizer::ExpandShiftByCons
                        DAG.getNode(ISD::SRL, DL, NVT, InL,
                                    DAG.getConstant(Amt, DL, ShTy)),
                        DAG.getNode(ISD::SHL, DL, NVT, InH,
-                                   DAG.getConstant(NVTBits - Amt, DL, ShTy)));
+                                   DAG.getConstant(-Amt + NVTBits, DL, ShTy)));
       Hi = DAG.getNode(ISD::SRL, DL, NVT, InH, DAG.getConstant(Amt, DL, ShTy));
     }
     return;
   }
 
   assert(N->getOpcode() == ISD::SRA && "Unknown shift!");
-  if (Amt > VTBits) {
+  if (Amt.ugt(VTBits)) {
     Hi = Lo = DAG.getNode(ISD::SRA, DL, NVT, InH,
                           DAG.getConstant(NVTBits - 1, DL, ShTy));
-  } else if (Amt > NVTBits) {
+  } else if (Amt.ugt(NVTBits)) {
     Lo = DAG.getNode(ISD::SRA, DL, NVT, InH,
-                     DAG.getConstant(Amt-NVTBits, DL, ShTy));
+                     DAG.getConstant(Amt - NVTBits, DL, ShTy));
     Hi = DAG.getNode(ISD::SRA, DL, NVT, InH,
                      DAG.getConstant(NVTBits - 1, DL, ShTy));
   } else if (Amt == NVTBits) {
@@ -1450,7 +1449,7 @@ void DAGTypeLegalizer::ExpandShiftByCons
                      DAG.getNode(ISD::SRL, DL, NVT, InL,
                                  DAG.getConstant(Amt, DL, ShTy)),
                      DAG.getNode(ISD::SHL, DL, NVT, InH,
-                                 DAG.getConstant(NVTBits - Amt, DL, ShTy)));
+                                 DAG.getConstant(-Amt + NVTBits, DL, ShTy)));
     Hi = DAG.getNode(ISD::SRA, DL, NVT, InH, DAG.getConstant(Amt, DL, ShTy));
   }
 }
@@ -2178,7 +2177,7 @@ void DAGTypeLegalizer::ExpandIntRes_Shif
   // If we can emit an efficient shift operation, do so now.  Check to see if
   // the RHS is a constant.
   if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(N->getOperand(1)))
-    return ExpandShiftByConstant(N, CN->getZExtValue(), Lo, Hi);
+    return ExpandShiftByConstant(N, CN->getAPIntValue(), Lo, Hi);
 
   // If we can determine that the high bit of the shift is zero or one, even if
   // the low bits are variable, emit this shift in an optimized form.

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h?rev=241806&r1=241805&r2=241806&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.h Thu Jul  9 09:58:04 2015
@@ -167,7 +167,7 @@ private:
   SDValue GetVectorElementPointer(SDValue VecPtr, EVT EltVT, SDValue Index);
   SDValue JoinIntegers(SDValue Lo, SDValue Hi);
   SDValue LibCallify(RTLIB::Libcall LC, SDNode *N, bool isSigned);
-  
+
   std::pair<SDValue, SDValue> ExpandChainLibCall(RTLIB::Libcall LC,
                                                  SDNode *Node, bool isSigned);
   std::pair<SDValue, SDValue> ExpandAtomic(SDNode *Node);
@@ -347,7 +347,7 @@ private:
 
   void ExpandIntRes_ATOMIC_LOAD       (SDNode *N, SDValue &Lo, SDValue &Hi);
 
-  void ExpandShiftByConstant(SDNode *N, unsigned Amt,
+  void ExpandShiftByConstant(SDNode *N, const APInt &Amt,
                              SDValue &Lo, SDValue &Hi);
   bool ExpandShiftWithKnownAmountBit(SDNode *N, SDValue &Lo, SDValue &Hi);
   bool ExpandShiftWithUnknownAmountBit(SDNode *N, SDValue &Lo, SDValue &Hi);

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=241806&r1=241805&r2=241806&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Thu Jul  9 09:58:04 2015
@@ -23167,7 +23167,7 @@ static SDValue PerformSHLCombine(SDNode
       // We shift all of the values by one. In many cases we do not have
       // hardware support for this operation. This is better expressed as an ADD
       // of two values.
-      if (N1SplatC->getZExtValue() == 1)
+      if (N1SplatC->getAPIntValue() == 1)
         return DAG.getNode(ISD::ADD, SDLoc(N), VT, N0, N0);
     }
 

Added: llvm/trunk/test/CodeGen/X86/legalize-shl-vec.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/legalize-shl-vec.ll?rev=241806&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/X86/legalize-shl-vec.ll (added)
+++ llvm/trunk/test/CodeGen/X86/legalize-shl-vec.ll Thu Jul  9 09:58:04 2015
@@ -0,0 +1,44 @@
+; RUN: llc < %s -march=x86-64 | FileCheck %s
+
+define <2 x i256> @test_shl(<2 x i256> %In) {
+  %Amt = insertelement <2 x i256> undef, i256 -1, i32 0
+  %Out = shl <2 x i256> %In, %Amt
+  ret <2 x i256> %Out
+
+  ; CHECK-LABEL: test_shl
+  ; CHECK:       movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK:       retq
+}
+
+define <2 x i256> @test_srl(<2 x i256> %In) {
+  %Amt = insertelement <2 x i256> undef, i256 -1, i32 0
+  %Out = lshr <2 x i256> %In, %Amt
+  ret <2 x i256> %Out
+
+  ; CHECK-LABEL: test_srl
+  ; CHECK:       movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK-NEXT:  movq $0
+  ; CHECK:       retq
+}
+
+define <2 x i256> @test_sra(<2 x i256> %In) {
+  %Amt = insertelement <2 x i256> undef, i256 -1, i32 0
+  %Out = ashr <2 x i256> %In, %Amt
+  ret <2 x i256> %Out
+
+  ; CHECK-LABEL: test_sra
+  ; CHECK:       sarq $63
+}





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