Replace a big gob of old coalescer logic with the new CoalescerPair class.

CoalescerPair can determine if a copy can be coalesced, and which register gets
merged away. The old logic in SimpleRegisterCoalescing had evolved into
something a bit too convoluted.

This second attempt fixes some crashes that only occurred Linux.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106769 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/CodeGen/LiveIntervalAnalysis.h

@@ -133,10 +133,9 @@ namespace llvm {
     bool conflictsWithPhysReg(const LiveInterval &li, VirtRegMap &vrm,
                               unsigned reg);
 
-    /// conflictsWithSubPhysRegRef - Similar to conflictsWithPhysRegRef except
-    /// it checks for sub-register reference and it can check use as well.
-    bool conflictsWithSubPhysRegRef(LiveInterval &li, unsigned Reg,
-                                    bool CheckUse,
+    /// conflictsWithAliasRef - Similar to conflictsWithPhysRegRef except
+    /// it checks for alias uses and defs.
+    bool conflictsWithAliasRef(LiveInterval &li, unsigned Reg,
                                    SmallPtrSet<MachineInstr*,32> &JoinedCopies);
 
     // Interval creation

lib/CodeGen/LiveIntervalAnalysis.cpp

@@ -218,10 +218,7 @@ bool LiveIntervals::conflictsWithPhysReg(const LiveInterval &li,
   return false;
 }
 
-/// conflictsWithSubPhysRegRef - Similar to conflictsWithPhysRegRef except
-/// it checks for sub-register reference and it can check use as well.
-bool LiveIntervals::conflictsWithSubPhysRegRef(LiveInterval &li,
-                                            unsigned Reg, bool CheckUse,
+bool LiveIntervals::conflictsWithAliasRef(LiveInterval &li, unsigned Reg,
                                   SmallPtrSet<MachineInstr*,32> &JoinedCopies) {
   for (LiveInterval::Ranges::const_iterator
          I = li.ranges.begin(), E = li.ranges.end(); I != E; ++I) {
@@ -239,12 +236,11 @@ bool LiveIntervals::conflictsWithSubPhysRegRef(LiveInterval &li,
         MachineOperand& MO = MI->getOperand(i);
         if (!MO.isReg())
           continue;
-        if (MO.isUse() && !CheckUse)
-          continue;
         unsigned PhysReg = MO.getReg();
-        if (PhysReg == 0 || TargetRegisterInfo::isVirtualRegister(PhysReg))
+        if (PhysReg == 0 || PhysReg == Reg ||
+            TargetRegisterInfo::isVirtualRegister(PhysReg))
           continue;
-        if (tri_->isSubRegister(Reg, PhysReg))
+        if (tri_->regsOverlap(Reg, PhysReg))
           return true;
       }
     }

lib/CodeGen/SimpleRegisterCoalescing.h

@@ -107,12 +107,9 @@ namespace llvm {
     bool JoinCopy(CopyRec &TheCopy, bool &Again);
 
     /// JoinIntervals - Attempt to join these two intervals.  On failure, this
-    /// returns false.  Otherwise, if one of the intervals being joined is a
-    /// physreg, this method always canonicalizes DestInt to be it.  The output
-    /// "SrcInt" will not have been modified, so we can use this information
-    /// below to update aliases.
-    bool JoinIntervals(LiveInterval &LHS, LiveInterval &RHS, bool &Swapped,
-                       CoalescerPair &CP);
+    /// returns false.  The output "SrcInt" will not have been modified, so we can
+    /// use this information below to update aliases.
+    bool JoinIntervals(CoalescerPair &CP);
 
     /// Return true if the two specified registers belong to different register
     /// classes.  The registers may be either phys or virt regs.
@@ -149,11 +146,6 @@ namespace llvm {
     bool ReMaterializeTrivialDef(LiveInterval &SrcInt, unsigned DstReg,
                                  unsigned DstSubIdx, MachineInstr *CopyMI);
 
-    /// CanCoalesceWithImpDef - Returns true if the specified copy instruction
-    /// from an implicit def to another register can be coalesced away.
-    bool CanCoalesceWithImpDef(MachineInstr *CopyMI,
-                               LiveInterval &li, LiveInterval &ImpLi) const;
-
     /// isWinToJoinCrossClass - Return true if it's profitable to coalesce
     /// two virtual registers from different register classes.
     bool isWinToJoinCrossClass(unsigned SrcReg,
@@ -162,31 +154,12 @@ namespace llvm {
                                const TargetRegisterClass *DstRC,
                                const TargetRegisterClass *NewRC);
 
-    /// HasIncompatibleSubRegDefUse - If we are trying to coalesce a virtual
-    /// register with a physical register, check if any of the virtual register
-    /// operand is a sub-register use or def. If so, make sure it won't result
-    /// in an illegal extract_subreg or insert_subreg instruction.
-    bool HasIncompatibleSubRegDefUse(MachineInstr *CopyMI,
-                                     unsigned VirtReg, unsigned PhysReg);
-
-    /// CanJoinExtractSubRegToPhysReg - Return true if it's possible to coalesce
-    /// an extract_subreg where dst is a physical register, e.g.
-    /// cl = EXTRACT_SUBREG reg1024, 1
-    bool CanJoinExtractSubRegToPhysReg(unsigned DstReg, unsigned SrcReg,
-                                       unsigned SubIdx, unsigned &RealDstReg);
-
-    /// CanJoinInsertSubRegToPhysReg - Return true if it's possible to coalesce
-    /// an insert_subreg where src is a physical register, e.g.
-    /// reg1024 = INSERT_SUBREG reg1024, c1, 0
-    bool CanJoinInsertSubRegToPhysReg(unsigned DstReg, unsigned SrcReg,
-                                      unsigned SubIdx, unsigned &RealDstReg);
-
     /// UpdateRegDefsUses - Replace all defs and uses of SrcReg to DstReg and
     /// update the subregister number if it is not zero. If DstReg is a
     /// physical register and the existing subregister number of the def / use
     /// being updated is not zero, make sure to set it to the correct physical
     /// subregister.
-    void UpdateRegDefsUses(unsigned SrcReg, unsigned DstReg, unsigned SubIdx);
+    void UpdateRegDefsUses(const CoalescerPair &CP);
 
     /// ShortenDeadCopyLiveRange - Shorten a live range defined by a dead copy.
     /// Return true if live interval is removed.
@@ -203,6 +176,10 @@ namespace llvm {
     /// it as well.
     bool RemoveDeadDef(LiveInterval &li, MachineInstr *DefMI);
 
+    /// RemoveCopyFlag - If DstReg is no longer defined by CopyMI, clear the
+    /// VNInfo copy flag for DstReg and all aliases.
+    void RemoveCopyFlag(unsigned DstReg, const MachineInstr *CopyMI);
+
     /// lastRegisterUse - Returns the last use of the specific register between
     /// cycles Start and End or NULL if there are no uses.
     MachineOperand *lastRegisterUse(SlotIndex Start, SlotIndex End,

test/CodeGen/ARM/vget_lane.ll

@@ -204,8 +204,8 @@ define <4 x i32> @vsetQ_lane32(<4 x i32>* %A, i32 %B) nounwind {
 
 define arm_aapcs_vfpcc <2 x float> @test_vset_lanef32(float %arg0_float32_t, <2 x float> %arg1_float32x2_t) nounwind {
 ;CHECK: test_vset_lanef32:
-;CHECK: vmov.f32
-;CHECK: vmov.f32
+;CHECK: vmov.f32 s3, s0
+;CHECK: vmov.f64 d0, d1
 entry:
   %0 = insertelement <2 x float> %arg1_float32x2_t, float %arg0_float32_t, i32 1 ; <<2 x float>> [#uses=1]
   ret <2 x float> %0