Add support for using the FLAGS result of or, xor, and and instructions
on x86, to avoid explicit test instructions. A few existing tests changed
due to arbitrary register allocation differences.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@82263 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp
index 11cc678..6154d26 100644
--- a/lib/Target/X86/X86ISelLowering.cpp
+++ b/lib/Target/X86/X86ISelLowering.cpp
@@ -5363,21 +5363,48 @@
Opcode = X86ISD::ADD;
NumOperands = 2;
break;
+ case ISD::AND: {
+ // If the primary and result isn't used, don't bother using X86ISD::AND,
+ // because a TEST instruction will be better.
+ bool NonFlagUse = false;
+ for (SDNode::use_iterator UI = Op.getNode()->use_begin(),
+ UE = Op.getNode()->use_end(); UI != UE; ++UI)
+ if (UI->getOpcode() != ISD::BRCOND &&
+ UI->getOpcode() != ISD::SELECT &&
+ UI->getOpcode() != ISD::SETCC) {
+ NonFlagUse = true;
+ break;
+ }
+ if (!NonFlagUse)
+ break;
+ }
+ // FALL THROUGH
case ISD::SUB:
- // Due to the ISEL shortcoming noted above, be conservative if this sub is
+ case ISD::OR:
+ case ISD::XOR:
+ // Due to the ISEL shortcoming noted above, be conservative if this op is
// likely to be selected as part of a load-modify-store instruction.
for (SDNode::use_iterator UI = Op.getNode()->use_begin(),
UE = Op.getNode()->use_end(); UI != UE; ++UI)
if (UI->getOpcode() == ISD::STORE)
goto default_case;
- // Otherwise use a regular EFLAGS-setting sub.
- Opcode = X86ISD::SUB;
+ // Otherwise use a regular EFLAGS-setting instruction.
+ switch (Op.getNode()->getOpcode()) {
+ case ISD::SUB: Opcode = X86ISD::SUB; break;
+ case ISD::OR: Opcode = X86ISD::OR; break;
+ case ISD::XOR: Opcode = X86ISD::XOR; break;
+ case ISD::AND: Opcode = X86ISD::AND; break;
+ default: llvm_unreachable("unexpected operator!");
+ }
NumOperands = 2;
break;
case X86ISD::ADD:
case X86ISD::SUB:
case X86ISD::INC:
case X86ISD::DEC:
+ case X86ISD::OR:
+ case X86ISD::XOR:
+ case X86ISD::AND:
return SDValue(Op.getNode(), 1);
default:
default_case:
@@ -5605,7 +5632,10 @@
Opc == X86ISD::SMUL ||
Opc == X86ISD::UMUL ||
Opc == X86ISD::INC ||
- Opc == X86ISD::DEC))
+ Opc == X86ISD::DEC ||
+ Opc == X86ISD::OR ||
+ Opc == X86ISD::XOR ||
+ Opc == X86ISD::AND))
return true;
return false;
@@ -7133,6 +7163,9 @@
case X86ISD::UMUL: return "X86ISD::UMUL";
case X86ISD::INC: return "X86ISD::INC";
case X86ISD::DEC: return "X86ISD::DEC";
+ case X86ISD::OR: return "X86ISD::OR";
+ case X86ISD::XOR: return "X86ISD::XOR";
+ case X86ISD::AND: return "X86ISD::AND";
case X86ISD::MUL_IMM: return "X86ISD::MUL_IMM";
case X86ISD::PTEST: return "X86ISD::PTEST";
case X86ISD::VASTART_SAVE_XMM_REGS: return "X86ISD::VASTART_SAVE_XMM_REGS";
@@ -8094,6 +8127,9 @@
case X86ISD::UMUL:
case X86ISD::INC:
case X86ISD::DEC:
+ case X86ISD::OR:
+ case X86ISD::XOR:
+ case X86ISD::AND:
// These nodes' second result is a boolean.
if (Op.getResNo() == 0)
break;