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| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2009-11-30 22:55:54 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2009-11-30 22:55:54 +0000 |
| commit | ce7a663140e6e67cf5ef7091e076e8541300c15a (patch) | |
| tree | 1cd89c92d53bdb96df8824ce5c153900845c7334 /lib/CodeGen/LiveIntervalAnalysis.cpp | |
| parent | b25846e1807ab8cb4cc3594458283947fb9e9e39 (diff) | |
New virtual registers created for spill intervals should inherit allocation hints from the original register.
This helps us avoid silly copies when rematting values that are copied to a physical register:
leaq _.str44(%rip), %rcx
movq %rcx, %rsi
call _strcmp
becomes:
leaq _.str44(%rip), %rsi
call _strcmp
The coalescer will not touch the movq because that would tie down the physical register.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@90163 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/LiveIntervalAnalysis.cpp')
| -rw-r--r-- | lib/CodeGen/LiveIntervalAnalysis.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/CodeGen/LiveIntervalAnalysis.cpp b/lib/CodeGen/LiveIntervalAnalysis.cpp index 4412c1b020..24adf364e7 100644 --- a/lib/CodeGen/LiveIntervalAnalysis.cpp +++ b/lib/CodeGen/LiveIntervalAnalysis.cpp @@ -1095,6 +1095,12 @@ rewriteInstructionForSpills(const LiveInterval &li, const VNInfo *VNI, NewVReg = mri_->createVirtualRegister(rc); vrm.grow(); CreatedNewVReg = true; + + // The new virtual register should get the same allocation hints as the + // old one. + std::pair<unsigned, unsigned> Hint = mri_->getRegAllocationHint(Reg); + if (Hint.first || Hint.second) + mri_->setRegAllocationHint(NewVReg, Hint.first, Hint.second); } if (!TryFold) |