From 879caeadf3d5c60a3f5f8cb3262adb8d51c2b4a0 Mon Sep 17 00:00:00 2001 From: Evan Cheng Date: Fri, 11 Sep 2009 01:01:31 +0000 Subject: Follow up to 81494. When the folded reload is narrowed to a 32-bit load then change the destination register to a 32-bit one or add a sub-register index. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81496 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Target/X86/X86InstrInfo.cpp | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'lib') diff --git a/lib/Target/X86/X86InstrInfo.cpp b/lib/Target/X86/X86InstrInfo.cpp index 46e63b2d3b..859ad57725 100644 --- a/lib/Target/X86/X86InstrInfo.cpp +++ b/lib/Target/X86/X86InstrInfo.cpp @@ -2206,6 +2206,7 @@ X86InstrInfo::foldMemoryOperandImpl(MachineFunction &MF, unsigned MinAlign = I->second.second; if (Align < MinAlign) return NULL; + bool NarrowToMOV32rm = false; if (Size) { unsigned RCSize = MI->getDesc().OpInfo[i].getRegClass(&RI)->getSize(); if (Size < RCSize) { @@ -2216,7 +2217,10 @@ X86InstrInfo::foldMemoryOperandImpl(MachineFunction &MF, // If this is a 64-bit load, but the spill slot is 32, then we can do // a 32-bit load which is implicitly zero-extended. This likely is due // to liveintervalanalysis remat'ing a load from stack slot. + if (MI->getOperand(0).getSubReg() || MI->getOperand(1).getSubReg()) + return NULL; Opcode = X86::MOV32rm; + NarrowToMOV32rm = true; } } @@ -2224,6 +2228,18 @@ X86InstrInfo::foldMemoryOperandImpl(MachineFunction &MF, NewMI = FuseTwoAddrInst(MF, Opcode, MOs, MI, *this); else NewMI = FuseInst(MF, Opcode, i, MOs, MI, *this); + + if (NarrowToMOV32rm) { + // If this is the special case where we use a MOV32rm to load a 32-bit + // value and zero-extend the top bits. Change the destination register + // to a 32-bit one. + unsigned DstReg = NewMI->getOperand(0).getReg(); + if (TargetRegisterInfo::isPhysicalRegister(DstReg)) + NewMI->getOperand(0).setReg(RI.getSubReg(DstReg, + 4/*x86_subreg_32bit*/)); + else + NewMI->getOperand(0).setSubReg(4/*x86_subreg_32bit*/); + } return NewMI; } } -- cgit v1.2.3