Drop the REDEF_BY_EC VNInfo flag.

A live range that has an early clobber tied redef now looks like a
normal tied redef, except the early clobber def uses the early clobber
slot.

This is enough to handle any strange interference problems.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149769 91177308-0d34-0410-b5e6-96231b3b80d8

4 files changed, 2 insertions, 51 deletions

diff --git a/include/llvm/CodeGen/LiveInterval.h b/include/llvm/CodeGen/LiveInterval.h
index 96f15483f3..a6008ab337 100644
--- a/include/llvm/CodeGen/LiveInterval.h
+++ b/include/llvm/CodeGen/LiveInterval.h
@@ -43,9 +43,8 @@ namespace llvm {
   private:
     enum {
       HAS_PHI_KILL    = 1,
-      REDEF_BY_EC     = 1 << 1,
-      IS_PHI_DEF      = 1 << 2,
-      IS_UNUSED       = 1 << 3
+      IS_PHI_DEF      = 1 << 1,
+      IS_UNUSED       = 1 << 2
     };
 
     unsigned char flags;
@@ -95,17 +94,6 @@ namespace llvm {
         flags &= ~HAS_PHI_KILL;
     }
 
-    /// Returns true if this value is re-defined by an early clobber somewhere
-    /// during the live range.
-    bool hasRedefByEC() const { return flags & REDEF_BY_EC; }
-    /// Set the "redef by early clobber" flag on this value.
-    void setHasRedefByEC(bool hasRedef) {
-      if (hasRedef)
-        flags |= REDEF_BY_EC;
-      else
-        flags &= ~REDEF_BY_EC;
-    }
-
     /// Returns true if this value is defined by a PHI instruction (or was,
     /// PHI instrucions may have been eliminated).
     bool isPHIDef() const { return flags & IS_PHI_DEF; }
diff --git a/lib/CodeGen/LiveInterval.cpp b/lib/CodeGen/LiveInterval.cpp
index f05574ee62..ac18843ac3 100644
--- a/lib/CodeGen/LiveInterval.cpp
+++ b/lib/CodeGen/LiveInterval.cpp
@@ -642,8 +642,6 @@ void LiveInterval::print(raw_ostream &OS, const TargetRegisterInfo *TRI) const {
           OS << "-phidef";
         if (vni->hasPHIKill())
           OS << "-phikill";
-        if (vni->hasRedefByEC())
-          OS << "-ec";
       }
     }
   }
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index d72009ccd2..cea75ef4b4 100644
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -432,8 +432,6 @@ exit:
   bool Extend = ValNo != 0;
   if (!Extend)
     ValNo = interval.getNextValue(start, VNInfoAllocator);
-  if (Extend && MO.isEarlyClobber())
-    ValNo->setHasRedefByEC(true);
   LiveRange LR(start, end, ValNo);
   interval.addRange(LR);
   DEBUG(dbgs() << " +" << LR << '\n');
diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp
index 3cd42c466f..cc9ec3ce14 100644
--- a/lib/CodeGen/RegisterCoalescer.cpp
+++ b/lib/CodeGen/RegisterCoalescer.cpp
@@ -438,27 +438,6 @@ bool RegisterCoalescer::AdjustCopiesBackFrom(const CoalescerPair &CP,
   // The live range might not exist after fun with physreg coalescing.
   if (ALR == IntA.end()) return false;
   VNInfo *AValNo = ALR->valno;
-  // If it's re-defined by an early clobber somewhere in the live range, then
-  // it's not safe to eliminate the copy. FIXME: This is a temporary workaround.
-  // See PR3149:
-  // 172     %ECX<def> = MOV32rr %reg1039<kill>
-  // 180     INLINEASM <es:subl $5,$1
-  //         sbbl $3,$0>, 10, %EAX<def>, 14, %ECX<earlyclobber,def>, 9,
-  //         %EAX<kill>,
-  // 36, <fi#0>, 1, %reg0, 0, 9, %ECX<kill>, 36, <fi#1>, 1, %reg0, 0
-  // 188     %EAX<def> = MOV32rr %EAX<kill>
-  // 196     %ECX<def> = MOV32rr %ECX<kill>
-  // 204     %ECX<def> = MOV32rr %ECX<kill>
-  // 212     %EAX<def> = MOV32rr %EAX<kill>
-  // 220     %EAX<def> = MOV32rr %EAX
-  // 228     %reg1039<def> = MOV32rr %ECX<kill>
-  // The early clobber operand ties ECX input to the ECX def.
-  //
-  // The live interval of ECX is represented as this:
-  // %reg20,inf = [46,47:1)[174,230:0)  0@174-(230) 1@46-(47)
-  // The coalescer has no idea there was a def in the middle of [174,230].
-  if (AValNo->hasRedefByEC())
-    return false;
 
   // If AValNo is defined as a copy from IntB, we can potentially process this.
   // Get the instruction that defines this value number.
@@ -1510,10 +1489,6 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) {
     if (!MI->isCopyLike())  // Src not defined by a copy?
       continue;
 
-    // Never join with a register that has EarlyClobber redefs.
-    if (VNI->hasRedefByEC())
-      return false;
-
     // Figure out the value # from the RHS.
     LiveRange *lr = RHS.getLiveRangeContaining(VNI->def.getPrevSlot());
     // The copy could be to an aliased physreg.
@@ -1540,10 +1515,6 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) {
     if (!MI->isCopyLike())  // Src not defined by a copy?
       continue;
 
-    // Never join with a register that has EarlyClobber redefs.
-    if (VNI->hasRedefByEC())
-      return false;
-
     // Figure out the value # from the LHS.
     LiveRange *lr = LHS.getLiveRangeContaining(VNI->def.getPrevSlot());
     // The copy could be to an aliased physreg.
@@ -1624,10 +1595,6 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) {
       if (LHSValNoAssignments[I->valno->id] !=
           RHSValNoAssignments[J->valno->id])
         return false;
-      // If it's re-defined by an early clobber somewhere in the live range,
-      // then conservatively abort coalescing.
-      if (NewVNInfo[LHSValNoAssignments[I->valno->id]]->hasRedefByEC())
-        return false;
     }
 
     if (I->end < J->end)