[llvm-commits] CVS: llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
Chris Lattner
lattner at cs.uiuc.edu
Wed Aug 30 23:48:40 PDT 2006
Changes in directory llvm/lib/CodeGen:
LiveIntervalAnalysis.cpp updated: 1.175 -> 1.176
---
Log message:
Add a special case that speeds up coallescing a bit, but not enough.
---
Diffs of the changes: (+107 -51)
LiveIntervalAnalysis.cpp | 158 +++++++++++++++++++++++++++++++----------------
1 files changed, 107 insertions(+), 51 deletions(-)
Index: llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
diff -u llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.175 llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.176
--- llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.175 Thu Aug 31 00:58:59 2006
+++ llvm/lib/CodeGen/LiveIntervalAnalysis.cpp Thu Aug 31 01:48:26 2006
@@ -886,46 +886,8 @@
/// "RHS" will not have been modified, so we can use this information
/// below to update aliases.
bool LiveIntervals::JoinIntervals(LiveInterval &LHS, LiveInterval &RHS) {
- // Loop over the value numbers of the LHS, seeing if any are defined from the
- // RHS.
- SmallVector<int, 16> LHSValsDefinedFromRHS;
- LHSValsDefinedFromRHS.resize(LHS.getNumValNums(), -1);
- for (unsigned VN = 0, e = LHS.getNumValNums(); VN != e; ++VN) {
- unsigned ValSrcReg = LHS.getSrcRegForValNum(VN);
- if (ValSrcReg == 0) // Src not defined by a copy?
- continue;
-
- // DstReg is known to be a register in the LHS interval. If the src is from
- // the RHS interval, we can use its value #.
- if (rep(ValSrcReg) != RHS.reg)
- continue;
-
- // Figure out the value # from the RHS.
- unsigned ValInst = LHS.getInstForValNum(VN);
- LHSValsDefinedFromRHS[VN] = RHS.getLiveRangeContaining(ValInst-1)->ValId;
- }
-
- // Loop over the value numbers of the RHS, seeing if any are defined from the
- // LHS.
- SmallVector<int, 16> RHSValsDefinedFromLHS;
- RHSValsDefinedFromLHS.resize(RHS.getNumValNums(), -1);
- for (unsigned VN = 0, e = RHS.getNumValNums(); VN != e; ++VN) {
- unsigned ValSrcReg = RHS.getSrcRegForValNum(VN);
- if (ValSrcReg == 0) // Src not defined by a copy?
- continue;
-
- // DstReg is known to be a register in the RHS interval. If the src is from
- // the LHS interval, we can use its value #.
- if (rep(ValSrcReg) != LHS.reg)
- continue;
-
- // Figure out the value # from the LHS.
- unsigned ValInst = RHS.getInstForValNum(VN);
- RHSValsDefinedFromLHS[VN] = LHS.getLiveRangeContaining(ValInst-1)->ValId;
- }
-
- // Now that we know the value mapping, compute the final value assignment,
- // assuming that the live ranges can be coallesced.
+ // Compute the final value assignment, assuming that the live ranges can be
+ // coallesced.
SmallVector<int, 16> LHSValNoAssignments;
SmallVector<int, 16> RHSValNoAssignments;
SmallVector<std::pair<unsigned,unsigned>, 16> ValueNumberInfo;
@@ -933,17 +895,111 @@
RHSValNoAssignments.resize(RHS.getNumValNums(), -1);
// Compute ultimate value numbers for the LHS and RHS values.
- for (unsigned VN = 0, e = LHS.getNumValNums(); VN != e; ++VN) {
- if (LHS.getInstForValNum(VN) == ~2U) continue;
- ComputeUltimateVN(VN, ValueNumberInfo,
- LHSValsDefinedFromRHS, RHSValsDefinedFromLHS,
- LHSValNoAssignments, RHSValNoAssignments, LHS, RHS);
- }
- for (unsigned VN = 0, e = RHS.getNumValNums(); VN != e; ++VN) {
- if (RHS.getInstForValNum(VN) == ~2U) continue;
- ComputeUltimateVN(VN, ValueNumberInfo,
- RHSValsDefinedFromLHS, LHSValsDefinedFromRHS,
- RHSValNoAssignments, LHSValNoAssignments, RHS, LHS);
+ if (RHS.containsOneValue()) {
+ // Copies from a liveinterval with a single value are simple to handle and
+ // very common, handle the special case here. This is important, because
+ // often RHS is small and LHS is large (e.g. a physreg).
+
+ // Find out if the RHS is defined as a copy from some value in the LHS.
+ int RHSValID = -1;
+ std::pair<unsigned,unsigned> RHSValNoInfo;
+ if (unsigned RHSSrcReg = RHS.getSrcRegForValNum(0)) {
+ if (rep(RHSSrcReg) != LHS.reg) {
+ RHSValNoInfo = RHS.getValNumInfo(0);
+ } else {
+ // It was defined as a copy from the LHS, find out what value # it is.
+ unsigned ValInst = RHS.getInstForValNum(0);
+ RHSValID = LHS.getLiveRangeContaining(ValInst-1)->ValId;
+ RHSValNoInfo = LHS.getValNumInfo(RHSValID);
+ }
+ } else {
+ RHSValNoInfo = RHS.getValNumInfo(0);
+ }
+
+ ValueNumberInfo.resize(LHS.getNumValNums());
+
+ // Okay, *all* of the values in LHS that are defined as a copy from RHS
+ // should now get updated.
+ for (unsigned VN = 0, e = LHS.getNumValNums(); VN != e; ++VN) {
+ if (unsigned LHSSrcReg = LHS.getSrcRegForValNum(VN)) {
+ if (rep(LHSSrcReg) != RHS.reg) {
+ // If this is not a copy from the RHS, its value number will be
+ // unmodified by the coallescing.
+ ValueNumberInfo[VN] = LHS.getValNumInfo(VN);
+ LHSValNoAssignments[VN] = VN;
+ } else if (RHSValID == -1) {
+ // Otherwise, it is a copy from the RHS, and we don't already have a
+ // value# for it. Keep the current value number, but remember it.
+ LHSValNoAssignments[VN] = RHSValID = VN;
+ ValueNumberInfo[VN] = RHSValNoInfo;
+ } else {
+ // Otherwise, use the specified value #.
+ LHSValNoAssignments[VN] = RHSValID;
+ if (VN != (unsigned)RHSValID)
+ ValueNumberInfo[VN].first = ~1U;
+ else
+ ValueNumberInfo[VN] = RHSValNoInfo;
+ }
+ } else {
+ ValueNumberInfo[VN] = LHS.getValNumInfo(VN);
+ LHSValNoAssignments[VN] = VN;
+ }
+ }
+
+ assert(RHSValID != -1 && "Didn't find value #?");
+ RHSValNoAssignments[0] = RHSValID;
+
+ } else {
+ // Loop over the value numbers of the LHS, seeing if any are defined from the
+ // RHS.
+ SmallVector<int, 16> LHSValsDefinedFromRHS;
+ LHSValsDefinedFromRHS.resize(LHS.getNumValNums(), -1);
+ for (unsigned VN = 0, e = LHS.getNumValNums(); VN != e; ++VN) {
+ unsigned ValSrcReg = LHS.getSrcRegForValNum(VN);
+ if (ValSrcReg == 0) // Src not defined by a copy?
+ continue;
+
+ // DstReg is known to be a register in the LHS interval. If the src is from
+ // the RHS interval, we can use its value #.
+ if (rep(ValSrcReg) != RHS.reg)
+ continue;
+
+ // Figure out the value # from the RHS.
+ unsigned ValInst = LHS.getInstForValNum(VN);
+ LHSValsDefinedFromRHS[VN] = RHS.getLiveRangeContaining(ValInst-1)->ValId;
+ }
+
+ // Loop over the value numbers of the RHS, seeing if any are defined from the
+ // LHS.
+ SmallVector<int, 16> RHSValsDefinedFromLHS;
+ RHSValsDefinedFromLHS.resize(RHS.getNumValNums(), -1);
+ for (unsigned VN = 0, e = RHS.getNumValNums(); VN != e; ++VN) {
+ unsigned ValSrcReg = RHS.getSrcRegForValNum(VN);
+ if (ValSrcReg == 0) // Src not defined by a copy?
+ continue;
+
+ // DstReg is known to be a register in the RHS interval. If the src is from
+ // the LHS interval, we can use its value #.
+ if (rep(ValSrcReg) != LHS.reg)
+ continue;
+
+ // Figure out the value # from the LHS.
+ unsigned ValInst = RHS.getInstForValNum(VN);
+ RHSValsDefinedFromLHS[VN] = LHS.getLiveRangeContaining(ValInst-1)->ValId;
+ }
+
+ for (unsigned VN = 0, e = LHS.getNumValNums(); VN != e; ++VN) {
+ if (LHS.getInstForValNum(VN) == ~2U) continue;
+ ComputeUltimateVN(VN, ValueNumberInfo,
+ LHSValsDefinedFromRHS, RHSValsDefinedFromLHS,
+ LHSValNoAssignments, RHSValNoAssignments, LHS, RHS);
+ }
+ for (unsigned VN = 0, e = RHS.getNumValNums(); VN != e; ++VN) {
+ if (RHS.getInstForValNum(VN) == ~2U) continue;
+ ComputeUltimateVN(VN, ValueNumberInfo,
+ RHSValsDefinedFromLHS, LHSValsDefinedFromRHS,
+ RHSValNoAssignments, LHSValNoAssignments, RHS, LHS);
+ }
}
// Armed with the mappings of LHS/RHS values to ultimate values, walk the
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