From 5f65b24e4df944e0dbab75aa4ee7efd12a1f820e Mon Sep 17 00:00:00 2001 From: Richard Sandiford Date: Fri, 13 Dec 2013 15:46:55 +0000 Subject: [PATCH] [SystemZ] Make more use of TMHH This originally came about after noticing that InstCombine turns some of the TMHH (icmp (and...), ...) tests into plain comparisons. Since there is no instruction to compare with a 64-bit immediate, TMHH is generally better than an ordered comparison for the cases that it can handle. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@197238 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/SystemZ/SystemZISelLowering.cpp | 78 ++++++++++----- test/CodeGen/SystemZ/int-cmp-47.ll | 109 +++++++++++++++++++++ 2 files changed, 162 insertions(+), 25 deletions(-) diff --git a/lib/Target/SystemZ/SystemZISelLowering.cpp b/lib/Target/SystemZ/SystemZISelLowering.cpp index 49547d319eb..6c443b59f79 100644 --- a/lib/Target/SystemZ/SystemZISelLowering.cpp +++ b/lib/Target/SystemZ/SystemZISelLowering.cpp @@ -1440,47 +1440,75 @@ static void adjustForTestUnderMask(SelectionDAG &DAG, Comparison &C) { uint64_t CmpVal = ConstOp1->getZExtValue(); // Check whether the nonconstant input is an AND with a constant mask. - if (C.Op0.getOpcode() != ISD::AND) - return; - SDValue AndOp0 = C.Op0.getOperand(0); - SDValue AndOp1 = C.Op0.getOperand(1); - ConstantSDNode *Mask = dyn_cast(AndOp1.getNode()); - if (!Mask) - return; - uint64_t MaskVal = Mask->getZExtValue(); + Comparison NewC(C); + uint64_t MaskVal; + ConstantSDNode *Mask = 0; + if (C.Op0.getOpcode() == ISD::AND) { + NewC.Op0 = C.Op0.getOperand(0); + NewC.Op1 = C.Op0.getOperand(1); + Mask = dyn_cast(NewC.Op1); + if (!Mask) + return; + MaskVal = Mask->getZExtValue(); + } else { + // There is no instruction to compare with a 64-bit immediate + // so use TMHH instead if possible. We need an unsigned ordered + // comparison with an i64 immediate. + if (NewC.Op0.getValueType() != MVT::i64 || + NewC.CCMask == SystemZ::CCMASK_CMP_EQ || + NewC.CCMask == SystemZ::CCMASK_CMP_NE || + NewC.ICmpType == SystemZICMP::SignedOnly) + return; + // Convert LE and GT comparisons into LT and GE. + if (NewC.CCMask == SystemZ::CCMASK_CMP_LE || + NewC.CCMask == SystemZ::CCMASK_CMP_GT) { + if (CmpVal == uint64_t(-1)) + return; + CmpVal += 1; + NewC.CCMask ^= SystemZ::CCMASK_CMP_EQ; + } + // If the low N bits of Op1 are zero than the low N bits of Op0 can + // be masked off without changing the result. + MaskVal = -(CmpVal & -CmpVal); + NewC.ICmpType = SystemZICMP::UnsignedOnly; + } // Check whether the combination of mask, comparison value and comparison // type are suitable. - unsigned BitSize = C.Op0.getValueType().getSizeInBits(); + unsigned BitSize = NewC.Op0.getValueType().getSizeInBits(); unsigned NewCCMask, ShiftVal; - if (C.ICmpType != SystemZICMP::SignedOnly && - AndOp0.getOpcode() == ISD::SHL && - isSimpleShift(AndOp0, ShiftVal) && - (NewCCMask = getTestUnderMaskCond(BitSize, C.CCMask, MaskVal >> ShiftVal, + if (NewC.ICmpType != SystemZICMP::SignedOnly && + NewC.Op0.getOpcode() == ISD::SHL && + isSimpleShift(NewC.Op0, ShiftVal) && + (NewCCMask = getTestUnderMaskCond(BitSize, NewC.CCMask, + MaskVal >> ShiftVal, CmpVal >> ShiftVal, SystemZICMP::Any))) { - AndOp0 = AndOp0.getOperand(0); - AndOp1 = DAG.getConstant(MaskVal >> ShiftVal, AndOp0.getValueType()); - } else if (C.ICmpType != SystemZICMP::SignedOnly && - AndOp0.getOpcode() == ISD::SRL && - isSimpleShift(AndOp0, ShiftVal) && - (NewCCMask = getTestUnderMaskCond(BitSize, C.CCMask, + NewC.Op0 = NewC.Op0.getOperand(0); + MaskVal >>= ShiftVal; + } else if (NewC.ICmpType != SystemZICMP::SignedOnly && + NewC.Op0.getOpcode() == ISD::SRL && + isSimpleShift(NewC.Op0, ShiftVal) && + (NewCCMask = getTestUnderMaskCond(BitSize, NewC.CCMask, MaskVal << ShiftVal, CmpVal << ShiftVal, SystemZICMP::UnsignedOnly))) { - AndOp0 = AndOp0.getOperand(0); - AndOp1 = DAG.getConstant(MaskVal << ShiftVal, AndOp0.getValueType()); + NewC.Op0 = NewC.Op0.getOperand(0); + MaskVal <<= ShiftVal; } else { - NewCCMask = getTestUnderMaskCond(BitSize, C.CCMask, MaskVal, CmpVal, - C.ICmpType); + NewCCMask = getTestUnderMaskCond(BitSize, NewC.CCMask, MaskVal, CmpVal, + NewC.ICmpType); if (!NewCCMask) return; } // Go ahead and make the change. C.Opcode = SystemZISD::TM; - C.Op0 = AndOp0; - C.Op1 = AndOp1; + C.Op0 = NewC.Op0; + if (Mask && Mask->getZExtValue() == MaskVal) + C.Op1 = SDValue(Mask, 0); + else + C.Op1 = DAG.getConstant(MaskVal, C.Op0.getValueType()); C.CCValid = SystemZ::CCMASK_TM; C.CCMask = NewCCMask; } diff --git a/test/CodeGen/SystemZ/int-cmp-47.ll b/test/CodeGen/SystemZ/int-cmp-47.ll index 9ebcbfe525b..038a25b2a6e 100644 --- a/test/CodeGen/SystemZ/int-cmp-47.ll +++ b/test/CodeGen/SystemZ/int-cmp-47.ll @@ -232,3 +232,112 @@ store: exit: ret void } + +; Check a case where TMHH can be used to implement a ult comparison. +define void @f13(i64 %a) { +; CHECK-LABEL: f13: +; CHECK: tmhh %r2, 49152 +; CHECK: jno {{\.L.*}} +; CHECK: br %r14 +entry: + %cmp = icmp ult i64 %a, 13835058055282163712 + br i1 %cmp, label %exit, label %store + +store: + store i32 1, i32 *@g + br label %exit + +exit: + ret void +} + +; And again with ule. +define void @f14(i64 %a) { +; CHECK-LABEL: f14: +; CHECK: tmhh %r2, 49152 +; CHECK: jno {{\.L.*}} +; CHECK: br %r14 +entry: + %cmp = icmp ule i64 %a, 13835058055282163711 + br i1 %cmp, label %exit, label %store + +store: + store i32 1, i32 *@g + br label %exit + +exit: + ret void +} + +; And again with ugt. +define void @f15(i64 %a) { +; CHECK-LABEL: f15: +; CHECK: tmhh %r2, 49152 +; CHECK: jo {{\.L.*}} +; CHECK: br %r14 +entry: + %cmp = icmp ugt i64 %a, 13835058055282163711 + br i1 %cmp, label %exit, label %store + +store: + store i32 1, i32 *@g + br label %exit + +exit: + ret void +} + +; And again with uge. +define void @f16(i64 %a) { +; CHECK-LABEL: f16: +; CHECK: tmhh %r2, 49152 +; CHECK: jo {{\.L.*}} +; CHECK: br %r14 +entry: + %cmp = icmp uge i64 %a, 13835058055282163712 + br i1 %cmp, label %exit, label %store + +store: + store i32 1, i32 *@g + br label %exit + +exit: + ret void +} + +; Decrease the constant from f13 to make TMHH invalid. +define void @f17(i64 %a) { +; CHECK-LABEL: f17: +; CHECK-NOT: tmhh +; CHECK: llihh {{%r[0-5]}}, 49151 +; CHECK-NOT: tmhh +; CHECK: br %r14 +entry: + %cmp = icmp ult i64 %a, 13834776580305453056 + br i1 %cmp, label %exit, label %store + +store: + store i32 1, i32 *@g + br label %exit + +exit: + ret void +} + +; Check that we don't use TMHH just to test the top bit. +define void @f18(i64 %a) { +; CHECK-LABEL: f18: +; CHECK-NOT: tmhh +; CHECK: cgijhe %r2, 0, +; CHECK: br %r14 +entry: + %cmp = icmp ult i64 %a, 9223372036854775808 + br i1 %cmp, label %exit, label %store + +store: + store i32 1, i32 *@g + br label %exit + +exit: + ret void +} -- 2.34.1