[llvm-commits] [llvm] r157103 - /llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp

[Jakob Stoklund Olesen]

Author: stoklund
Date: Sat May 19 00:25:56 2012
New Revision: 157103

URL: http://llvm.org/viewvc/llvm-project?rev=157103&view=rev
Log:
Don't remat during updateRegDefsUses().

Remaining virtreg->physreg copies were rematerialized during
updateRegDefsUses(), but we already do the same thing in joinCopy() when
visiting the physreg copy instruction.

Eliminate the preserveSrcInt argument to reMaterializeTrivialDef(). It
is now always true.

Modified:
    llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp

Modified: llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp?rev=157103&r1=157102&r2=157103&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp (original)
+++ llvm/trunk/lib/CodeGen/RegisterCoalescer.cpp Sat May 19 00:25:56 2012
@@ -151,9 +151,8 @@
 
     /// reMaterializeTrivialDef - If the source of a copy is defined by a
     /// trivial computation, replace the copy by rematerialize the definition.
-    /// If PreserveSrcInt is true, make sure SrcInt is valid after the call.
-    bool reMaterializeTrivialDef(LiveInterval &SrcInt, bool PreserveSrcInt,
-                                 unsigned DstReg, MachineInstr *CopyMI);
+    bool reMaterializeTrivialDef(LiveInterval &SrcInt, unsigned DstReg,
+                                 MachineInstr *CopyMI);
 
     /// canJoinPhys - Return true if a physreg copy should be joined.
     bool canJoinPhys(CoalescerPair &CP);
@@ -784,7 +783,6 @@
 /// reMaterializeTrivialDef - If the source of a copy is defined by a trivial
 /// computation, replace the copy by rematerialize the definition.
 bool RegisterCoalescer::reMaterializeTrivialDef(LiveInterval &SrcInt,
-                                                bool preserveSrcInt,
                                                 unsigned DstReg,
                                                 MachineInstr *CopyMI) {
   SlotIndex CopyIdx = LIS->getInstructionIndex(CopyMI).getRegSlot(true);
@@ -872,8 +870,7 @@
   ++NumReMats;
 
   // The source interval can become smaller because we removed a use.
-  if (preserveSrcInt)
-    LIS->shrinkToUses(&SrcInt);
+  LIS->shrinkToUses(&SrcInt);
 
   return true;
 }
@@ -938,20 +935,6 @@
   for (MachineRegisterInfo::reg_iterator I = MRI->reg_begin(SrcReg);
        MachineInstr *UseMI = I.skipInstruction();) {
     bool AlreadyJoined = JoinedCopies.count(UseMI);
-
-    // A PhysReg copy that won't be coalesced can perhaps be rematerialized
-    // instead.
-    if (DstIsPhys) {
-      if (UseMI->isFullCopy() &&
-          UseMI->getOperand(1).getReg() == SrcReg &&
-          UseMI->getOperand(0).getReg() != SrcReg &&
-          UseMI->getOperand(0).getReg() != DstReg &&
-          !AlreadyJoined &&
-          reMaterializeTrivialDef(LIS->getInterval(SrcReg), false,
-                                  UseMI->getOperand(0).getReg(), UseMI))
-        continue;
-    }
-
     SmallVector<unsigned,8> Ops;
     bool Reads, Writes;
     tie(Reads, Writes) = UseMI->readsWritesVirtualRegister(SrcReg, &Ops);
@@ -1093,7 +1076,7 @@
       // Before giving up coalescing, if definition of source is defined by
       // trivial computation, try rematerializing it.
       if (!CP.isFlipped() &&
-          reMaterializeTrivialDef(LIS->getInterval(CP.getSrcReg()), true,
+          reMaterializeTrivialDef(LIS->getInterval(CP.getSrcReg()),
                                   CP.getDstReg(), CopyMI))
         return true;
       return false;
@@ -1128,7 +1111,7 @@
     // If definition of source is defined by trivial computation, try
     // rematerializing it.
     if (!CP.isFlipped() &&
-        reMaterializeTrivialDef(LIS->getInterval(CP.getSrcReg()), true,
+        reMaterializeTrivialDef(LIS->getInterval(CP.getSrcReg()),
                                 CP.getDstReg(), CopyMI))
       return true;