[llvm] r195399 - R600: Implement TargetInstrInfo::isLegalToSplitMBBAt()

[Tom Stellard]

Author: tstellar
Date: Thu Nov 21 18:41:08 2013
New Revision: 195399

URL: http://llvm.org/viewvc/llvm-project?rev=195399&view=rev
Log:
R600: Implement TargetInstrInfo::isLegalToSplitMBBAt()

Splitting a basic block will create a new ALU clause, so we need to make
sure we aren't moving uses of registers that are local to their
current clause into a new one.

I had a test case for this, but unfortunately unrelated schedule changes
invalidated it, and I wasn't been able to come up with another one.

NOTE: This is a candidate for the 3.4 branch.

Modified:
    llvm/trunk/lib/Target/R600/R600InstrInfo.cpp
    llvm/trunk/lib/Target/R600/R600InstrInfo.h

Modified: llvm/trunk/lib/Target/R600/R600InstrInfo.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/R600InstrInfo.cpp?rev=195399&r1=195398&r2=195399&view=diff
==============================================================================
--- llvm/trunk/lib/Target/R600/R600InstrInfo.cpp (original)
+++ llvm/trunk/lib/Target/R600/R600InstrInfo.cpp Thu Nov 21 18:41:08 2013
@@ -77,6 +77,18 @@ R600InstrInfo::copyPhysReg(MachineBasicB
   }
 }
 
+/// \returns true if \p MBBI can be moved into a new basic.
+bool R600InstrInfo::isLegalToSplitMBBAt(MachineBasicBlock &MBB,
+                                       MachineBasicBlock::iterator MBBI) const {
+  for (MachineInstr::const_mop_iterator I = MBBI->operands_begin(),
+                                        E = MBBI->operands_end(); I != E; ++I) {
+    if (I->isReg() && !TargetRegisterInfo::isVirtualRegister(I->getReg()) &&
+        I->isUse() && RI.isPhysRegLiveAcrossClauses(I->getReg()))
+      return false;
+  }
+  return true;
+}
+
 unsigned R600InstrInfo::getIEQOpcode() const {
   return AMDGPU::SETE_INT;
 }

Modified: llvm/trunk/lib/Target/R600/R600InstrInfo.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/R600/R600InstrInfo.h?rev=195399&r1=195398&r2=195399&view=diff
==============================================================================
--- llvm/trunk/lib/Target/R600/R600InstrInfo.h (original)
+++ llvm/trunk/lib/Target/R600/R600InstrInfo.h Thu Nov 21 18:41:08 2013
@@ -55,6 +55,8 @@ namespace llvm {
                            MachineBasicBlock::iterator MI, DebugLoc DL,
                            unsigned DestReg, unsigned SrcReg,
                            bool KillSrc) const;
+  bool isLegalToSplitMBBAt(MachineBasicBlock &MBB,
+                           MachineBasicBlock::iterator MBBI) const;
 
   bool isTrig(const MachineInstr &MI) const;
   bool isPlaceHolderOpcode(unsigned opcode) const;