Temporarily restore the scavenger implicit_def checking code. MachineOperand isUndef mark is not being put on implicit_def of physical registers (created for parameter passing, etc.).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74519 91177308-0d34-0410-b5e6-96231b3b80d8

3 files changed, 152 insertions, 7 deletions

diff --git a/include/llvm/CodeGen/RegisterScavenging.h b/include/llvm/CodeGen/RegisterScavenging.h
index 458c2e4487..a4ed0129eb 100644
--- a/include/llvm/CodeGen/RegisterScavenging.h
+++ b/include/llvm/CodeGen/RegisterScavenging.h
@@ -69,6 +69,10 @@ class RegScavenger {
   /// available, unset means the register is currently being used.
   BitVector RegsAvailable;
 
+  /// ImplicitDefed - If bit is set that means the register is defined by an
+  /// implicit_def instructions. That means it can be clobbered at will.
+  BitVector ImplicitDefed;
+
   /// CurrDist - Distance from MBB entry to the current instruction MBBI.
   ///
   unsigned CurrDist;
@@ -113,18 +117,25 @@ public:
   bool isUsed(unsigned Reg) const   { return !RegsAvailable[Reg]; }
   bool isUnused(unsigned Reg) const { return RegsAvailable[Reg]; }
 
+  bool isImplicitlyDefined(unsigned Reg) const { return ImplicitDefed[Reg]; }
+
   /// getRegsUsed - return all registers currently in use in used.
   void getRegsUsed(BitVector &used, bool includeReserved);
 
   /// setUsed / setUnused - Mark the state of one or a number of registers.
   ///
-  void setUsed(unsigned Reg);
-  void setUsed(BitVector &Regs) {
+  void setUsed(unsigned Reg, bool ImpDef = false);
+  void setUsed(BitVector &Regs, bool ImpDef = false) {
     RegsAvailable &= ~Regs;
+    if (ImpDef)
+      ImplicitDefed |= Regs;
+    else
+      ImplicitDefed &= ~Regs;
   }
   void setUnused(unsigned Reg, const MachineInstr *MI);
   void setUnused(BitVector &Regs) {
     RegsAvailable |= Regs;
+    ImplicitDefed &= ~Regs;
   }
 
   /// FindUnusedReg - Find a unused register of the specified register class
diff --git a/lib/CodeGen/RegisterScavenging.cpp b/lib/CodeGen/RegisterScavenging.cpp
index 7d8e3afa78..382741ee73 100644
--- a/lib/CodeGen/RegisterScavenging.cpp
+++ b/lib/CodeGen/RegisterScavenging.cpp
@@ -57,22 +57,28 @@ static bool RedefinesSuperRegPart(const MachineInstr *MI,
 }
 
 /// setUsed - Set the register and its sub-registers as being used.
-void RegScavenger::setUsed(unsigned Reg) {
+void RegScavenger::setUsed(unsigned Reg, bool ImpDef) {
   RegsAvailable.reset(Reg);
+  ImplicitDefed[Reg] = ImpDef;
 
   for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
-       unsigned SubReg = *SubRegs; ++SubRegs)
+       unsigned SubReg = *SubRegs; ++SubRegs) {
     RegsAvailable.reset(SubReg);
+    ImplicitDefed[SubReg] = ImpDef;
+  }
 }
 
 /// setUnused - Set the register and its sub-registers as being unused.
 void RegScavenger::setUnused(unsigned Reg, const MachineInstr *MI) {
   RegsAvailable.set(Reg);
+  ImplicitDefed.reset(Reg);
 
   for (const unsigned *SubRegs = TRI->getSubRegisters(Reg);
        unsigned SubReg = *SubRegs; ++SubRegs)
-    if (!RedefinesSuperRegPart(MI, Reg, TRI))
+    if (!RedefinesSuperRegPart(MI, Reg, TRI)) {
       RegsAvailable.set(SubReg);
+      ImplicitDefed.reset(SubReg);
+    }
 }
 
 void RegScavenger::enterBasicBlock(MachineBasicBlock *mbb) {
@@ -88,6 +94,7 @@ void RegScavenger::enterBasicBlock(MachineBasicBlock *mbb) {
   if (!MBB) {
     NumPhysRegs = TRI->getNumRegs();
     RegsAvailable.resize(NumPhysRegs);
+    ImplicitDefed.resize(NumPhysRegs);
 
     // Create reserved registers bitvector.
     ReservedRegs = TRI->getReservedRegs(MF);
@@ -106,6 +113,7 @@ void RegScavenger::enterBasicBlock(MachineBasicBlock *mbb) {
   ScavengeRestore = NULL;
   CurrDist = 0;
   DistanceMap.clear();
+  ImplicitDefed.reset();
 
   // All registers started out unused.
   RegsAvailable.set();
@@ -187,6 +195,8 @@ void RegScavenger::forward() {
     ScavengeRestore = NULL;
   }
 
+  bool IsImpDef = MI->getOpcode() == TargetInstrInfo::IMPLICIT_DEF;
+
   // Separate register operands into 3 classes: uses, defs, earlyclobbers.
   SmallVector<std::pair<const MachineOperand*,unsigned>, 4> UseMOs;
   SmallVector<std::pair<const MachineOperand*,unsigned>, 4> DefMOs;
@@ -211,7 +221,14 @@ void RegScavenger::forward() {
 
     assert(isUsed(Reg) && "Using an undefined register!");
 
-    if (MO.isKill() && !isReserved(Reg)) {
+    // Kill of implicit_def defined registers are ignored. e.g.
+    // entry: 0x2029ab8, LLVM BB @0x1b06080, ID#0:
+    // Live Ins: %R0
+    //  %R0<def> = IMPLICIT_DEF
+    //  %R0<def> = IMPLICIT_DEF
+    //  STR %R0<kill>, %R0, %reg0, 0, 14, %reg0, Mem:ST(4,4) [0x1b06510 + 0]
+    //  %R1<def> = LDR %R0, %reg0, 24, 14, %reg0, Mem:LD(4,4) [0x1b065bc + 0]
+    if (MO.isKill() && !isReserved(Reg) && !isImplicitlyDefined(Reg)) {
       KillRegs.set(Reg);
 
       // Mark sub-registers as used.
@@ -257,9 +274,10 @@ void RegScavenger::forward() {
     // Implicit def is allowed to "re-define" any register. Similarly,
     // implicitly defined registers can be clobbered.
     assert((isReserved(Reg) || isUnused(Reg) ||
+            IsImpDef || isImplicitlyDefined(Reg) ||
             isLiveInButUnusedBefore(Reg, MI, MBB, TRI, MRI)) &&
            "Re-defining a live register!");
-    setUsed(Reg);
+    setUsed(Reg, IsImpDef);
   }
 }
 
diff --git a/test/CodeGen/ARM/2009-06-30-RegScavengerAssert2.ll b/test/CodeGen/ARM/2009-06-30-RegScavengerAssert2.ll
new file mode 100644
index 0000000000..3a14d67247
--- /dev/null
+++ b/test/CodeGen/ARM/2009-06-30-RegScavengerAssert2.ll
@@ -0,0 +1,116 @@
+; RUN: llvm-as < %s | llc -march=arm -mtriple=armv6-apple-darwin9
+
+@no_mat = external global i32		; <i32*> [#uses=1]
+@no_mis = external global i32		; <i32*> [#uses=2]
+@"\01LC11" = external constant [33 x i8], align 1		; <[33 x i8]*> [#uses=1]
+@"\01LC15" = external constant [33 x i8], align 1		; <[33 x i8]*> [#uses=1]
+@"\01LC17" = external constant [47 x i8], align 1		; <[47 x i8]*> [#uses=1]
+
+declare arm_apcscc i32 @printf(i8* nocapture, ...) nounwind
+
+declare arm_apcscc void @diff(i8*, i8*, i32, i32, i32, i32) nounwind
+
+define arm_apcscc void @SIM(i8* %A, i8* %B, i32 %M, i32 %N, i32 %K, [256 x i32]* %V, i32 %Q, i32 %R, i32 %nseq) nounwind {
+entry:
+	br i1 undef, label %bb5, label %bb
+
+bb:		; preds = %bb, %entry
+	br label %bb
+
+bb5:		; preds = %entry
+	br i1 undef, label %bb6, label %bb8
+
+bb6:		; preds = %bb6, %bb5
+	br i1 undef, label %bb8, label %bb6
+
+bb8:		; preds = %bb6, %bb5
+	br label %bb15
+
+bb9:		; preds = %bb15
+	br i1 undef, label %bb10, label %bb11
+
+bb10:		; preds = %bb9
+	unreachable
+
+bb11:		; preds = %bb9
+	%0 = load i32* undef, align 4		; <i32> [#uses=3]
+	%1 = add i32 %0, 1		; <i32> [#uses=2]
+	store i32 %1, i32* undef, align 4
+	%2 = load i32* undef, align 4		; <i32> [#uses=2]
+	%3 = sub i32 %2, %0		; <i32> [#uses=1]
+	store i32 0, i32* @no_mat, align 4
+	store i32 0, i32* @no_mis, align 4
+	%4 = getelementptr i8* %B, i32 %0		; <i8*> [#uses=1]
+	tail call arm_apcscc  void @diff(i8* undef, i8* %4, i32 undef, i32 %3, i32 undef, i32 undef) nounwind
+	%5 = tail call arm_apcscc  i32 (i8*, ...)* @printf(i8* getelementptr ([33 x i8]* @"\01LC11", i32 0, i32 0), i32 %tmp13) nounwind		; <i32> [#uses=0]
+	%6 = load i32* @no_mis, align 4		; <i32> [#uses=1]
+	%7 = tail call arm_apcscc  i32 (i8*, ...)* @printf(i8* getelementptr ([33 x i8]* @"\01LC15", i32 0, i32 0), i32 %6) nounwind		; <i32> [#uses=0]
+	%8 = tail call arm_apcscc  i32 (i8*, ...)* @printf(i8* getelementptr ([47 x i8]* @"\01LC17", i32 0, i32 0), i32 undef, i32 %1, i32 undef, i32 %2) nounwind		; <i32> [#uses=0]
+	br i1 undef, label %bb15, label %bb12
+
+bb12:		; preds = %bb11
+	br label %bb228.i
+
+bb74.i:		; preds = %bb228.i
+	br i1 undef, label %bb138.i, label %bb145.i
+
+bb138.i:		; preds = %bb74.i
+	br label %bb145.i
+
+bb145.i:		; preds = %bb228.i, %bb138.i, %bb74.i
+	br i1 undef, label %bb146.i, label %bb151.i
+
+bb146.i:		; preds = %bb145.i
+	br i1 undef, label %bb228.i, label %bb151.i
+
+bb151.i:		; preds = %bb146.i, %bb145.i
+	br i1 undef, label %bb153.i, label %bb228.i
+
+bb153.i:		; preds = %bb151.i
+	br i1 undef, label %bb220.i, label %bb.nph.i98
+
+bb.nph.i98:		; preds = %bb153.i
+	br label %bb158.i
+
+bb158.i:		; preds = %bb218.i, %bb.nph.i98
+	br i1 undef, label %bb168.i, label %bb160.i
+
+bb160.i:		; preds = %bb158.i
+	br i1 undef, label %bb161.i, label %bb168.i
+
+bb161.i:		; preds = %bb160.i
+	br i1 undef, label %bb168.i, label %bb163.i
+
+bb163.i:		; preds = %bb161.i
+	br i1 undef, label %bb167.i, label %bb168.i
+
+bb167.i:		; preds = %bb163.i
+	br label %bb168.i
+
+bb168.i:		; preds = %bb167.i, %bb163.i, %bb161.i, %bb160.i, %bb158.i
+	br i1 undef, label %bb211.i, label %bb218.i
+
+bb211.i:		; preds = %bb168.i
+	br label %bb218.i
+
+bb218.i:		; preds = %bb211.i, %bb168.i
+	br i1 undef, label %bb220.i, label %bb158.i
+
+bb220.i:		; preds = %bb218.i, %bb153.i
+	br i1 undef, label %bb221.i, label %bb228.i
+
+bb221.i:		; preds = %bb220.i
+	br label %bb228.i
+
+bb228.i:		; preds = %bb221.i, %bb220.i, %bb151.i, %bb146.i, %bb12
+	br i1 undef, label %bb74.i, label %bb145.i
+
+bb15:		; preds = %bb11, %bb8
+	%indvar11 = phi i32 [ 0, %bb8 ], [ %tmp13, %bb11 ]		; <i32> [#uses=2]
+	%tmp13 = add i32 %indvar11, 1		; <i32> [#uses=2]
+	%count.0 = sub i32 undef, %indvar11		; <i32> [#uses=0]
+	br i1 undef, label %return, label %bb9
+
+return:		; preds = %bb15
+	ret void
+}