Fix MergeValueInAsValue(). It allows overlapping live ranges but should replace

their value numbers with the specified value number.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@43062 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2007-10-17 02:13:29 +00:00
parent 3f4b80ec0c
commit 3c1f4a4d47

View File

@ -19,6 +19,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/LiveInterval.h"
#include "llvm/ADT/SmallSet.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Support/Streams.h"
#include "llvm/Target/MRegisterInfo.h"
@ -386,19 +387,68 @@ void LiveInterval::MergeRangesInAsValue(const LiveInterval &RHS,
/// MergeValueInAsValue - Merge all of the live ranges of a specific val#
/// in RHS into this live interval as the specified value number.
/// The LiveRanges in RHS are allowed to overlap with LiveRanges in the
/// current interval, but only if the overlapping LiveRanges have the
/// specified value number.
/// current interval, it will replace the value numbers of the overlaped
/// live ranges with the specified value number.
void LiveInterval::MergeValueInAsValue(const LiveInterval &RHS,
const VNInfo *RHSValNo, VNInfo *LHSValNo) {
// TODO: Make this more efficient.
iterator InsertPos = begin();
SmallVector<VNInfo*, 4> ReplacedValNos;
iterator IP = begin();
for (const_iterator I = RHS.begin(), E = RHS.end(); I != E; ++I) {
if (I->valno != RHSValNo)
continue;
unsigned Start = I->start, End = I->end;
IP = std::upper_bound(IP, end(), Start);
// If the start of this range overlaps with an existing liverange, trim it.
if (IP != begin() && IP[-1].end > Start) {
if (IP->valno != LHSValNo) {
ReplacedValNos.push_back(IP->valno);
IP->valno = LHSValNo; // Update val#.
}
Start = IP[-1].end;
// Trimmed away the whole range?
if (Start >= End) continue;
}
// If the end of this range overlaps with an existing liverange, trim it.
if (IP != end() && End > IP->start) {
if (IP->valno != LHSValNo) {
ReplacedValNos.push_back(IP->valno);
IP->valno = LHSValNo; // Update val#.
}
End = IP->start;
// If this trimmed away the whole range, ignore it.
if (Start == End) continue;
}
// Map the valno in the other live range to the current live range.
LiveRange Tmp = *I;
Tmp.valno = LHSValNo;
InsertPos = addRangeFrom(Tmp, InsertPos);
IP = addRangeFrom(LiveRange(Start, End, LHSValNo), IP);
}
SmallSet<VNInfo*, 4> Seen;
for (unsigned i = 0, e = ReplacedValNos.size(); i != e; ++i) {
VNInfo *V1 = ReplacedValNos[i];
if (Seen.insert(V1)) {
bool isDead = true;
for (const_iterator I = begin(), E = end(); I != E; ++I)
if (I->valno == V1) {
isDead = false;
break;
}
if (isDead) {
// Now that V1 is dead, remove it. If it is the largest value number,
// just nuke it (and any other deleted values neighboring it), otherwise
// mark it as ~1U so it can be nuked later.
if (V1->id == getNumValNums()-1) {
do {
VNInfo *VNI = valnos.back();
valnos.pop_back();
VNI->~VNInfo();
} while (valnos.back()->def == ~1U);
} else {
V1->def = ~1U;
}
}
}
}
}