Changes in directory llvm/lib/CodeGen:
LiveIntervalAnalysis.cpp updated: 1.194 -> 1.195
---
Log message:
A register def can be partially dead when the whole register has use(s) but a
subreg does not.
---
Diffs of the changes: (+8 -1)
LiveIntervalAnalysis.cpp | 9 ++++++++-
1 files changed, 8 insertions(+), 1 deletion(-)
Index: llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
diff -u llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.194
llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.195
--- llvm/lib/CodeGen/LiveIntervalAnalysis.cpp:1.194 Fri Nov 10 02:38:19 2006
+++ llvm/lib/CodeGen/LiveIntervalAnalysis.cpp Wed Nov 15 14:54:11 2006
@@ -575,7 +575,6 @@
// A physical register cannot be live across basic block, so its
// lifetime must end somewhere in its defining basic block.
DEBUG(std::cerr << "\t\tregister: "; printRegName(interval.reg));
- typedef LiveVariables::killed_iterator KillIter;
unsigned baseIndex = MIIdx;
unsigned start = getDefIndex(baseIndex);
@@ -599,6 +598,14 @@
DEBUG(std::cerr << " killed");
end = getUseIndex(baseIndex) + 1;
goto exit;
+ } else if (lv_->ModifiesRegister(mi, interval.reg)) {
+ // Another instruction redefines the register before it is ever read.
+ // Then the register is essentially dead at the instruction that defines
+ // it. Hence its interval is:
+ // [defSlot(def), defSlot(def)+1)
+ DEBUG(std::cerr << " dead");
+ end = getDefIndex(start) + 1;
+ goto exit;
}
}
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