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| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-07-20 21:29:31 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-07-20 21:29:31 +0000 |
| commit | 2ec0cda5d5ede57022eb7dc5e7170f4fa420cb2b (patch) | |
| tree | caf2220e5305521a65d48afd793f2e608a285424 /lib/CodeGen/LiveRangeEdit.cpp | |
| parent | 7325f06051bab14196ab3701d515f5b110cefe26 (diff) | |
| download | llvm-2ec0cda5d5ede57022eb7dc5e7170f4fa420cb2b.tar.gz llvm-2ec0cda5d5ede57022eb7dc5e7170f4fa420cb2b.tar.bz2 llvm-2ec0cda5d5ede57022eb7dc5e7170f4fa420cb2b.tar.xz | |
Avoid folding loads that are unsafe to move.
LiveRangeEdit::foldAsLoad() can eliminate a register by folding a load
into its only use. Only do that when the load is safe to move, and it
won't extend any live ranges.
This fixes PR13414.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160575 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/LiveRangeEdit.cpp')
| -rw-r--r-- | lib/CodeGen/LiveRangeEdit.cpp | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/lib/CodeGen/LiveRangeEdit.cpp b/lib/CodeGen/LiveRangeEdit.cpp index 261d860e01..896fdbfbe2 100644 --- a/lib/CodeGen/LiveRangeEdit.cpp +++ b/lib/CodeGen/LiveRangeEdit.cpp @@ -177,6 +177,19 @@ bool LiveRangeEdit::foldAsLoad(LiveInterval *LI, if (!DefMI || !UseMI) return false; + // Since we're moving the DefMI load, make sure we're not extending any live + // ranges. + if (!allUsesAvailableAt(DefMI, + LIS.getInstructionIndex(DefMI), + LIS.getInstructionIndex(UseMI))) + return false; + + // We also need to make sure it is safe to move the load. + // Assume there are stores between DefMI and UseMI. + bool SawStore = true; + if (!DefMI->isSafeToMove(&TII, 0, SawStore)) + return false; + DEBUG(dbgs() << "Try to fold single def: " << *DefMI << " into single use: " << *UseMI); |