From dd669615dd604f5ac4d89c6c062cd8a7bf345f38 Mon Sep 17 00:00:00 2001 From: Hal Finkel Date: Thu, 15 Jan 2015 03:08:59 +0000 Subject: Revert "r226071 - [RegisterCoalescer] Remove copies to reserved registers" Reverting this while I investigate some bad behavior this is causing. As a possibly-related issue, adding -verify-machineinstrs to one of the test cases now fails because of this change: llc test/CodeGen/X86/2009-02-12-DebugInfoVLA.ll -march=x86-64 -o - -verify-machineinstrs *** Bad machine code: No instruction at def index *** - function: foo - basic block: BB#0 return (0x10007e21f10) [0B;736B) - liverange: [128r,128d:9)[160r,160d:8)[176r,176d:7)[336r,336d:6)[464r,464d:5)[480r,480d:4)[624r,624d:3)[752r,752d:2)[768r,768d:1)[78 4r,784d:0) 0@784r 1@768r 2@752r 3@624r 4@480r 5@464r 6@336r 7@176r 8@160r 9@128r - register: %DS Valno #3 is defined at 624r *** Bad machine code: Live segment doesn't end at a valid instruction *** - function: foo - basic block: BB#0 return (0x10007e21f10) [0B;736B) - liverange: [128r,128d:9)[160r,160d:8)[176r,176d:7)[336r,336d:6)[464r,464d:5)[480r,480d:4)[624r,624d:3)[752r,752d:2)[768r,768d:1)[78 4r,784d:0) 0@784r 1@768r 2@752r 3@624r 4@480r 5@464r 6@336r 7@176r 8@160r 9@128r - register: %DS [624r,624d:3) LLVM ERROR: Found 2 machine code errors. where 624r corresponds exactly to the interval combining change: 624B %RSP = COPY %vreg16; GR64:%vreg16 Considering merging %vreg16 with %RSP RHS = %vreg16 [608r,624r:0) 0@608r updated: 608B %RSP = MOV64rm , 1, %noreg, 0, %noreg; mem:LD8[%saved_stack.1] Success: %vreg16 -> %RSP Result = %RSP llvm-svn: 226086 --- llvm/lib/CodeGen/RegisterCoalescer.cpp | 20 +++++--------------- 1 file changed, 5 insertions(+), 15 deletions(-) (limited to 'llvm/lib/CodeGen') diff --git a/llvm/lib/CodeGen/RegisterCoalescer.cpp b/llvm/lib/CodeGen/RegisterCoalescer.cpp index 517bc2dbe12..b8cae4a59ed 100644 --- a/llvm/lib/CodeGen/RegisterCoalescer.cpp +++ b/llvm/lib/CodeGen/RegisterCoalescer.cpp @@ -1209,10 +1209,10 @@ bool RegisterCoalescer::canJoinPhys(const CoalescerPair &CP) { } LiveInterval &JoinVInt = LIS->getInterval(CP.getSrcReg()); - if (JoinVInt.containsOneValue()) + if (CP.isFlipped() && JoinVInt.containsOneValue()) return true; - DEBUG(dbgs() << "\tCannot join complex intervals into reserved register.\n"); + DEBUG(dbgs() << "\tCannot join defs into reserved register.\n"); return false; } @@ -1431,7 +1431,8 @@ bool RegisterCoalescer::joinReservedPhysReg(CoalescerPair &CP) { LiveInterval &RHS = LIS->getInterval(CP.getSrcReg()); DEBUG(dbgs() << "\t\tRHS = " << RHS << '\n'); - assert(RHS.containsOneValue() && "Invalid join with reserved register"); + assert(CP.isFlipped() && RHS.containsOneValue() && + "Invalid join with reserved register"); // Optimization for reserved registers like ESP. We can only merge with a // reserved physreg if RHS has a single value that is a copy of CP.DstReg(). @@ -1452,18 +1453,7 @@ bool RegisterCoalescer::joinReservedPhysReg(CoalescerPair &CP) { // defs are there. // Delete the identity copy. - MachineInstr *CopyMI; - if (CP.isFlipped()) { - CopyMI = MRI->getVRegDef(RHS.reg); - } else { - if (!MRI->hasOneNonDBGUse(RHS.reg)) { - DEBUG(dbgs() << "\t\tMultiple vreg uses\n"); - return false; - } - - CopyMI = &*MRI->use_instr_nodbg_begin(RHS.reg); - } - + MachineInstr *CopyMI = MRI->getVRegDef(RHS.reg); LIS->RemoveMachineInstrFromMaps(CopyMI); CopyMI->eraseFromParent(); -- cgit v1.2.3