diff options
Diffstat (limited to 'lib/Target/X86/X86ISelLowering.cpp')
| -rw-r--r-- | lib/Target/X86/X86ISelLowering.cpp | 19 |
1 files changed, 17 insertions, 2 deletions
diff --git a/lib/Target/X86/X86ISelLowering.cpp b/lib/Target/X86/X86ISelLowering.cpp index 4b30ff67c9..03eb57a408 100644 --- a/lib/Target/X86/X86ISelLowering.cpp +++ b/lib/Target/X86/X86ISelLowering.cpp @@ -10715,11 +10715,26 @@ SDValue X86TargetLowering::LowerBRCOND(SDValue Op, SelectionDAG &DAG) const { unsigned X86Opcode; unsigned X86Cond; SDVTList VTs; + // Keep this in sync with LowerXALUO, otherwise we might create redundant + // instructions that can't be removed afterwards (i.e. X86ISD::ADD and + // X86ISD::INC). switch (CondOpcode) { case ISD::UADDO: X86Opcode = X86ISD::ADD; X86Cond = X86::COND_B; break; - case ISD::SADDO: X86Opcode = X86ISD::ADD; X86Cond = X86::COND_O; break; + case ISD::SADDO: + if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS)) + if (C->isOne()) { + X86Opcode = X86ISD::INC; X86Cond = X86::COND_O; + break; + } + X86Opcode = X86ISD::ADD; X86Cond = X86::COND_O; break; case ISD::USUBO: X86Opcode = X86ISD::SUB; X86Cond = X86::COND_B; break; - case ISD::SSUBO: X86Opcode = X86ISD::SUB; X86Cond = X86::COND_O; break; + case ISD::SSUBO: + if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(RHS)) + if (C->isOne()) { + X86Opcode = X86ISD::DEC; X86Cond = X86::COND_O; + break; + } + X86Opcode = X86ISD::SUB; X86Cond = X86::COND_O; break; case ISD::UMULO: X86Opcode = X86ISD::UMUL; X86Cond = X86::COND_O; break; case ISD::SMULO: X86Opcode = X86ISD::SMUL; X86Cond = X86::COND_O; break; default: llvm_unreachable("unexpected overflowing operator"); |