If a re-materializable instruction has a register operand, the spiller will change...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@56835 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp
index bc66321b4af3d941d058fc894591651636e7bdb4..4ed456bf11ab07c611956661a857034212e72210 100644 (file)
--- a/lib/CodeGen/LiveIntervalAnalysis.cpp
+++ b/lib/CodeGen/LiveIntervalAnalysis.cpp
@@ -819,6 +819,7 @@ bool LiveIntervals::isValNoAvailableAt(const LiveInterval &li, MachineInstr *MI,
 /// val# of the specified interval is re-materializable.
 bool LiveIntervals::isReMaterializable(const LiveInterval &li,
                                        const VNInfo *ValNo, MachineInstr *MI,
+                                       SmallVectorImpl<LiveInterval*> &SpillIs,
                                        bool &isLoad) {
   if (DisableReMat)
     return false;
@@ -855,8 +856,8 @@ bool LiveIntervals::isReMaterializable(const LiveInterval &li,
 
     // If the instruction accesses memory and the memory could be non-constant,
     // assume the instruction is not rematerializable.
-    for (std::list<MachineMemOperand>::const_iterator I = MI->memoperands_begin(),
-         E = MI->memoperands_end(); I != E; ++I) {
+    for (std::list<MachineMemOperand>::const_iterator
+           I = MI->memoperands_begin(), E = MI->memoperands_end(); I != E; ++I){
       const MachineMemOperand &MMO = *I;
       if (MMO.isVolatile() || MMO.isStore())
         return false;
@@ -924,13 +925,21 @@ bool LiveIntervals::isReMaterializable(const LiveInterval &li,
       if (!isValNoAvailableAt(ImpLi, MI, UseIdx))
         return false;
     }
+
+    // If a register operand of the re-materialized instruction is going to
+    // be spilled next, then it's not legal to re-materialize this instruction.
+    for (unsigned i = 0, e = SpillIs.size(); i != e; ++i)
+      if (ImpUse == SpillIs[i]->reg)
+        return false;
   }
   return true;
 }
 
 /// isReMaterializable - Returns true if every definition of MI of every
 /// val# of the specified interval is re-materializable.
-bool LiveIntervals::isReMaterializable(const LiveInterval &li, bool &isLoad) {
+bool LiveIntervals::isReMaterializable(const LiveInterval &li,
+                                       SmallVectorImpl<LiveInterval*> &SpillIs,
+                                       bool &isLoad) {
   isLoad = false;
   for (LiveInterval::const_vni_iterator i = li.vni_begin(), e = li.vni_end();
        i != e; ++i) {
@@ -944,7 +953,7 @@ bool LiveIntervals::isReMaterializable(const LiveInterval &li, bool &isLoad) {
     MachineInstr *ReMatDefMI = getInstructionFromIndex(DefIdx);
     bool DefIsLoad = false;
     if (!ReMatDefMI ||
-        !isReMaterializable(li, VNI, ReMatDefMI, DefIsLoad))
+        !isReMaterializable(li, VNI, ReMatDefMI, SpillIs, DefIsLoad))
       return false;
     isLoad |= DefIsLoad;
   }
@@ -1728,6 +1737,7 @@ addIntervalsForSpillsFast(const LiveInterval &li,
 
 std::vector<LiveInterval*> LiveIntervals::
 addIntervalsForSpills(const LiveInterval &li,
+                      SmallVectorImpl<LiveInterval*> &SpillIs,
                       const MachineLoopInfo *loopInfo, VirtRegMap &vrm,
                       float &SSWeight) {
   
@@ -1831,7 +1841,7 @@ addIntervalsForSpills(const LiveInterval &li,
     MachineInstr *ReMatDefMI = (DefIdx == ~0u)
       ? 0 : getInstructionFromIndex(DefIdx);
     bool dummy;
-    if (ReMatDefMI && isReMaterializable(li, VNI, ReMatDefMI, dummy)) {
+    if (ReMatDefMI && isReMaterializable(li, VNI, ReMatDefMI, SpillIs, dummy)) {
       // Remember how to remat the def of this val#.
       ReMatOrigDefs[VN] = ReMatDefMI;
       // Original def may be modified so we have to make a copy here.

diff --git a/lib/CodeGen/RegAllocLinearScan.cpp b/lib/CodeGen/RegAllocLinearScan.cpp
index d834031ae6bc71cf373ccf493e8e4a12810fabf7..7291e12bbea438135a0ca0b7e0a9e7440f68c7ad 100644 (file)
--- a/lib/CodeGen/RegAllocLinearScan.cpp
+++ b/lib/CodeGen/RegAllocLinearScan.cpp
@@ -879,8 +879,9 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
   if (cur->weight != HUGE_VALF && cur->weight <= minWeight) {
     DOUT << "\t\t\tspilling(c): " << *cur << '\n';
     float SSWeight;
+    SmallVector<LiveInterval*, 8> spillIs;
     std::vector<LiveInterval*> added =
-      li_->addIntervalsForSpills(*cur, loopInfo, *vrm_, SSWeight);
+      li_->addIntervalsForSpills(*cur, spillIs, loopInfo, *vrm_, SSWeight);
     addStackInterval(cur, ls_, li_, SSWeight, *vrm_);
     if (added.empty())
       return;  // Early exit if all spills were folded.
@@ -931,7 +932,7 @@ void RALinScan::assignRegOrStackSlotAtInterval(LiveInterval* cur)
     earliestStart = std::min(earliestStart, sli->beginNumber());
     float SSWeight;
     std::vector<LiveInterval*> newIs =
-      li_->addIntervalsForSpills(*sli, loopInfo, *vrm_, SSWeight);
+      li_->addIntervalsForSpills(*sli, spillIs, loopInfo, *vrm_, SSWeight);
     addStackInterval(sli, ls_, li_, SSWeight, *vrm_);
     std::copy(newIs.begin(), newIs.end(), std::back_inserter(added));
     spilled.insert(sli->reg);

diff --git a/lib/CodeGen/SimpleRegisterCoalescing.cpp b/lib/CodeGen/SimpleRegisterCoalescing.cpp
index bdc37b16b6a05a93d5e96e75b47c223cf846bf5a..86065f069f73c40b392fbd87c4646c9ce698589d 100644 (file)
--- a/lib/CodeGen/SimpleRegisterCoalescing.cpp
+++ b/lib/CodeGen/SimpleRegisterCoalescing.cpp
@@ -2361,7 +2361,8 @@ bool SimpleRegisterCoalescing::runOnMachineFunction(MachineFunction &fn) {
         LI.weight = HUGE_VALF;
       else {
         bool isLoad = false;
-        if (li_->isReMaterializable(LI, isLoad)) {
+        SmallVector<LiveInterval*, 4> SpillIs;
+        if (li_->isReMaterializable(LI, SpillIs, isLoad)) {
           // If all of the definitions of the interval are re-materializable,
           // it is a preferred candidate for spilling. If non of the defs are
           // loads, then it's potentially very cheap to re-materialize.

diff --git a/test/CodeGen/X86/2008-09-29-ReMatBug.ll b/test/CodeGen/X86/2008-09-29-ReMatBug.ll
new file mode 100644 (file)
index 0000000..d4da01a
--- /dev/null
+++ b/test/CodeGen/X86/2008-09-29-ReMatBug.ll
@@ -0,0 +1,85 @@
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin -relocation-model=pic -disable-fp-elim
+
+       %struct..0objc_selector = type opaque
+       %struct.NSString = type opaque
+       %struct.XCStringList = type { i32, %struct._XCStringListNode* }
+       %struct._XCStringListNode = type { [3 x i8], [0 x i8], i8 }
+       %struct.__builtin_CFString = type { i32*, i32, i8*, i32 }
+internal constant %struct.__builtin_CFString { i32* getelementptr ([0 x i32]* @__CFConstantStringClassReference, i32 0, i32 0), i32 1992, i8* getelementptr ([3 x i8]* @"\01LC", i32 0, i32 0), i32 2 }                ; <%struct.__builtin_CFString*>:0 [#uses=1]
+@__CFConstantStringClassReference = external global [0 x i32]          ; <[0 x i32]*> [#uses=1]
+@"\01LC" = internal constant [3 x i8] c"NO\00"         ; <[3 x i8]*> [#uses=1]
+@"\01LC1" = internal constant [1 x i8] zeroinitializer         ; <[1 x i8]*> [#uses=1]
+@llvm.used1 = appending global [1 x i8*] [ i8* bitcast (%struct.NSString* (%struct.XCStringList*, %struct..0objc_selector*)* @"-[XCStringList stringRepresentation]" to i8*) ], section "llvm.metadata"                ; <[1 x i8*]*> [#uses=0]
+
+define %struct.NSString* @"-[XCStringList stringRepresentation]"(%struct.XCStringList* %self, %struct..0objc_selector* %_cmd) nounwind {
+entry:
+       %0 = load i32* null, align 4            ; <i32> [#uses=1]
+       %1 = and i32 %0, 16777215               ; <i32> [#uses=1]
+       %2 = icmp eq i32 %1, 0          ; <i1> [#uses=1]
+       br i1 %2, label %bb44, label %bb4
+
+bb4:           ; preds = %entry
+       %3 = load %struct._XCStringListNode** null, align 4             ; <%struct._XCStringListNode*> [#uses=2]
+       %4 = icmp eq %struct._XCStringListNode* %3, null                ; <i1> [#uses=1]
+       %5 = bitcast %struct._XCStringListNode* %3 to i32*              ; <i32*> [#uses=1]
+       br label %bb37.outer
+
+bb6:           ; preds = %bb37
+       br label %bb19
+
+bb19:          ; preds = %bb37, %bb6
+       %.rle = phi i32 [ 0, %bb6 ], [ %10, %bb37 ]             ; <i32> [#uses=1]
+       %bufptr.0.lcssa = phi i8* [ null, %bb6 ], [ null, %bb37 ]               ; <i8*> [#uses=2]
+       %6 = and i32 %.rle, 16777215            ; <i32> [#uses=1]
+       %7 = icmp eq i32 %6, 0          ; <i1> [#uses=1]
+       br i1 %7, label %bb25.split, label %bb37
+
+bb25.split:            ; preds = %bb19
+       call void @foo(i8* getelementptr ([1 x i8]* @"\01LC1", i32 0, i32 0)) nounwind nounwind
+       br label %bb35.outer
+
+bb34:          ; preds = %bb35, %bb35, %bb35, %bb35
+       %8 = getelementptr i8* %bufptr.0.lcssa, i32 %totalLength.0.ph           ; <i8*> [#uses=1]
+       store i8 92, i8* %8, align 1
+       br label %bb35.outer
+
+bb35.outer:            ; preds = %bb34, %bb25.split
+       %totalLength.0.ph = add i32 0, %totalLength.1.ph                ; <i32> [#uses=2]
+       br label %bb35
+
+bb35:          ; preds = %bb35, %bb35.outer
+       %9 = load i8* null, align 1             ; <i8> [#uses=1]
+       switch i8 %9, label %bb35 [
+               i8 0, label %bb37.outer
+               i8 32, label %bb34
+               i8 92, label %bb34
+               i8 34, label %bb34
+               i8 39, label %bb34
+       ]
+
+bb37.outer:            ; preds = %bb35, %bb4
+       %totalLength.1.ph = phi i32 [ 0, %bb4 ], [ %totalLength.0.ph, %bb35 ]           ; <i32> [#uses=1]
+       %bufptr.1.ph = phi i8* [ null, %bb4 ], [ %bufptr.0.lcssa, %bb35 ]               ; <i8*> [#uses=2]
+       br i1 %4, label %bb39.split, label %bb37
+
+bb37:          ; preds = %bb37.outer, %bb19
+       %10 = load i32* %5, align 4             ; <i32> [#uses=1]
+       br i1 false, label %bb6, label %bb19
+
+bb39.split:            ; preds = %bb37.outer
+       %11 = bitcast i8* null to %struct.NSString*             ; <%struct.NSString*> [#uses=2]
+       %12 = icmp eq i8* null, %bufptr.1.ph            ; <i1> [#uses=1]
+       br i1 %12, label %bb44, label %bb42
+
+bb42:          ; preds = %bb39.split
+       call void @quux(i8* %bufptr.1.ph) nounwind nounwind
+       ret %struct.NSString* %11
+
+bb44:          ; preds = %bb39.split, %entry
+       %.0 = phi %struct.NSString* [ bitcast (%struct.__builtin_CFString* @0 to %struct.NSString*), %entry ], [ %11, %bb39.split ]             ; <%struct.NSString*> [#uses=1]
+       ret %struct.NSString* %.0
+}
+
+declare void @foo(i8*)
+
+declare void @quux(i8*)