diff options
| -rw-r--r-- | lib/Target/X86/X86RegisterInfo.cpp | 23 |
1 files changed, 22 insertions, 1 deletions
diff --git a/lib/Target/X86/X86RegisterInfo.cpp b/lib/Target/X86/X86RegisterInfo.cpp index 9278516d05..da65db03e4 100644 --- a/lib/Target/X86/X86RegisterInfo.cpp +++ b/lib/Target/X86/X86RegisterInfo.cpp @@ -1236,7 +1236,28 @@ void X86RegisterInfo::emitPrologue(MachineFunction &MF) const { MBB.insert(MBBI, MI); } } else { - emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, TII); + // If there is an ADD32ri or SUB32ri of ESP immediately after this + // instruction, merge the two instructions. + if (MBBI != MBB.end()) { + MachineBasicBlock::iterator NI = next(MBBI); + unsigned Opc = MBBI->getOpcode(); + if ((Opc == X86::ADD64ri32 || Opc == X86::ADD64ri8 || + Opc == X86::ADD32ri || Opc == X86::ADD32ri8) && + MBBI->getOperand(0).getReg() == StackPtr) { + NumBytes -= MBBI->getOperand(2).getImm(); + MBB.erase(MBBI); + MBBI = NI; + } else if ((Opc == X86::SUB64ri32 || Opc == X86::SUB64ri8 || + Opc == X86::SUB32ri || Opc == X86::SUB32ri8) && + MBBI->getOperand(0).getReg() == StackPtr) { + NumBytes += MBBI->getOperand(2).getImm(); + MBB.erase(MBBI); + MBBI = NI; + } + } + + if (NumBytes) + emitSPUpdate(MBB, MBBI, StackPtr, -(int64_t)NumBytes, Is64Bit, TII); } } |