Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp =================================================================== --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -6023,6 +6023,9 @@ /// Otherwise, returns an expansion of \p ExtractFrom based on the following /// patterns: /// +/// (or (add v v) (shrl v c)): +/// expands (add v v) -> (shl v 1) +/// /// (or (mul v c0) (shrl (mul v c1) c2)): /// expands (mul v c0) -> (shl (mul v c1) c3) /// @@ -6045,6 +6048,22 @@ "Existing shift must be valid as a rotate half"); ExtractFrom = stripConstantMask(DAG, ExtractFrom, Mask); + + // Value and Type of the shift. + SDValue OppShiftLHS = OppShift.getOperand(0); + EVT ShiftedVT = OppShiftLHS.getValueType(); + + // Amount of the existing shift. + ConstantSDNode *OppShiftCst = isConstOrConstSplat(OppShift.getOperand(1)); + + // (add v v) -> (shl v 1) + if (OppShift.getOpcode() == ISD::SRL && OppShiftCst && + ExtractFrom.getOpcode() == ISD::ADD && + ExtractFrom.getOperand(0) == ExtractFrom.getOperand(1) && + OppShiftCst->getAPIntValue() == ShiftedVT.getScalarSizeInBits() - 1) + return DAG.getNode(ISD::SHL, DL, ShiftedVT, OppShiftLHS, + DAG.getShiftAmountConstant(1, ShiftedVT, DL)); + // Preconditions: // (or (op0 v c0) (shiftl/r (op0 v c1) c2)) // @@ -6068,15 +6087,11 @@ // op0 must be the same opcode on both sides, have the same LHS argument, // and produce the same value type. - SDValue OppShiftLHS = OppShift.getOperand(0); - EVT ShiftedVT = OppShiftLHS.getValueType(); if (OppShiftLHS.getOpcode() != ExtractFrom.getOpcode() || OppShiftLHS.getOperand(0) != ExtractFrom.getOperand(0) || ShiftedVT != ExtractFrom.getValueType()) return SDValue(); - // Amount of the existing shift. - ConstantSDNode *OppShiftCst = isConstOrConstSplat(OppShift.getOperand(1)); // Constant mul/udiv/shift amount from the RHS of the shift's LHS op. ConstantSDNode *OppLHSCst = isConstOrConstSplat(OppShiftLHS.getOperand(1)); // Constant mul/udiv/shift amount from the RHS of the ExtractFrom op. Index: test/CodeGen/X86/rotate-extract-vector.ll =================================================================== --- test/CodeGen/X86/rotate-extract-vector.ll +++ test/CodeGen/X86/rotate-extract-vector.ll @@ -285,12 +285,26 @@ define <4 x i32> @extract_add_1(<4 x i32> %i) nounwind { ; CHECK-LABEL: extract_add_1: ; CHECK: # %bb.0: +; CHECK-NEXT: # kill: def $xmm0 killed $xmm0 def $zmm0 +; CHECK-NEXT: vprold $1, %zmm0, %zmm0 +; CHECK-NEXT: # kill: def $xmm0 killed $xmm0 killed $zmm0 +; CHECK-NEXT: vzeroupper +; CHECK-NEXT: ret{{[l|q]}} + %ii = add <4 x i32> %i, %i + %rhs = lshr <4 x i32> %i, + %out = or <4 x i32> %ii, %rhs + ret <4 x i32> %out +} + +define <4 x i32> @no_extract_add_1(<4 x i32> %i) nounwind { +; CHECK-LABEL: no_extract_add_1: +; CHECK: # %bb.0: ; CHECK-NEXT: vpaddd %xmm0, %xmm0, %xmm1 -; CHECK-NEXT: vpsrld $31, %xmm0, %xmm0 +; CHECK-NEXT: vpsrld $27, %xmm0, %xmm0 ; CHECK-NEXT: vpor %xmm0, %xmm1, %xmm0 ; CHECK-NEXT: ret{{[l|q]}} %ii = add <4 x i32> %i, %i - %rhs = lshr <4 x i32> %i, + %rhs = lshr <4 x i32> %i, %out = or <4 x i32> %ii, %rhs ret <4 x i32> %out } Index: test/CodeGen/X86/rotate-extract.ll =================================================================== --- test/CodeGen/X86/rotate-extract.ll +++ test/CodeGen/X86/rotate-extract.ll @@ -270,21 +270,39 @@ define i32 @extract_add_1(i32 %i) nounwind { ; X86-LABEL: extract_add_1: ; X86: # %bb.0: +; X86-NEXT: movl {{[0-9]+}}(%esp), %eax +; X86-NEXT: roll %eax +; X86-NEXT: retl +; +; X64-LABEL: extract_add_1: +; X64: # %bb.0: +; X64-NEXT: movl %edi, %eax +; X64-NEXT: roll %eax +; X64-NEXT: retq + %ii = add i32 %i, %i + %rhs = lshr i32 %i, 31 + %out = or i32 %ii, %rhs + ret i32 %out +} + +define i32 @no_extract_add_1(i32 %i) nounwind { +; X86-LABEL: no_extract_add_1: +; X86: # %bb.0: ; X86-NEXT: movl {{[0-9]+}}(%esp), %ecx ; X86-NEXT: leal (%ecx,%ecx), %eax -; X86-NEXT: shrl $31, %ecx +; X86-NEXT: shrl $27, %ecx ; X86-NEXT: orl %ecx, %eax ; X86-NEXT: retl ; -; X64-LABEL: extract_add_1: +; X64-LABEL: no_extract_add_1: ; X64: # %bb.0: ; X64-NEXT: # kill: def $edi killed $edi def $rdi ; X64-NEXT: leal (%rdi,%rdi), %eax -; X64-NEXT: shrl $31, %edi +; X64-NEXT: shrl $27, %edi ; X64-NEXT: orl %edi, %eax ; X64-NEXT: retq %ii = add i32 %i, %i - %rhs = lshr i32 %i, 31 + %rhs = lshr i32 %i, 27 %out = or i32 %ii, %rhs ret i32 %out }