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author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2011-02-08 18:50:21 +0000 |
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committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2011-02-08 18:50:21 +0000 |
commit | 5c716bdccce2fa504e1aa0b67226165d181d2459 (patch) | |
tree | a3521d6a1e177037b2e620c3585ed3f0a462cd0a /lib/CodeGen/SplitKit.h | |
parent | 01cb34b0111a1e8792f327b56c51bc3bbaf83aca (diff) | |
download | llvm-5c716bdccce2fa504e1aa0b67226165d181d2459.tar.gz llvm-5c716bdccce2fa504e1aa0b67226165d181d2459.tar.bz2 llvm-5c716bdccce2fa504e1aa0b67226165d181d2459.tar.xz |
Add SplitEditor::overlapIntv() to create small ranges where both registers are live.
If a live range is used by a terminator instruction, and that live range needs
to leave the block on the stack or in a different register, it can be necessary
to have both sides of the split live at the terminator instruction.
Example:
%vreg2 = COPY %vreg1
JMP %vreg1
Becomes after spilling %vreg2:
SPILL %vreg1
JMP %vreg1
The spill doesn't kill the register as is normally the case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@125102 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SplitKit.h')
-rw-r--r-- | lib/CodeGen/SplitKit.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/lib/CodeGen/SplitKit.h b/lib/CodeGen/SplitKit.h index 205341c19c..4614796e70 100644 --- a/lib/CodeGen/SplitKit.h +++ b/lib/CodeGen/SplitKit.h @@ -377,6 +377,18 @@ public: /// Return the end of the live range. SlotIndex leaveIntvAtTop(MachineBasicBlock &MBB); + /// overlapIntv - Indicate that all instructions in range should use the open + /// interval, but also let the complement interval be live. + /// + /// This doubles the register pressure, but is sometimes required to deal with + /// register uses after the last valid split point. + /// + /// The Start index should be a return value from a leaveIntv* call, and End + /// should be in the same basic block. The parent interval must have the same + /// value across the range. + /// + void overlapIntv(SlotIndex Start, SlotIndex End); + /// closeIntv - Indicate that we are done editing the currently open /// LiveInterval, and ranges can be trimmed. void closeIntv(); |