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| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-05-20 18:42:55 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-05-20 18:42:55 +0000 |
| commit | 418a3638acfa95e4212a38100adfc2f8cdd45919 (patch) | |
| tree | 48bc0964867915ac874907257e508515ef9ccc90 /lib | |
| parent | 0fda545c2c164dc607f48f4b77f54c35bcafa413 (diff) | |
| download | external_llvm-418a3638acfa95e4212a38100adfc2f8cdd45919.zip external_llvm-418a3638acfa95e4212a38100adfc2f8cdd45919.tar.gz external_llvm-418a3638acfa95e4212a38100adfc2f8cdd45919.tar.bz2 | |
Constrain regclasses in PeepholeOptimizer.
It can be necessary to restrict to a sub-class before accessing
sub-registers.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@157164 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/CodeGen/PeepholeOptimizer.cpp | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/lib/CodeGen/PeepholeOptimizer.cpp b/lib/CodeGen/PeepholeOptimizer.cpp index ab672c9..81cf901 100644 --- a/lib/CodeGen/PeepholeOptimizer.cpp +++ b/lib/CodeGen/PeepholeOptimizer.cpp @@ -150,6 +150,13 @@ optimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB, // No other uses. return false; + // Ensure DstReg can get a register class that actually supports + // sub-registers. Don't change the class until we commit. + const TargetRegisterClass *DstRC = MRI->getRegClass(DstReg); + DstRC = TM->getRegisterInfo()->getSubClassWithSubReg(DstRC, SubIdx); + if (!DstRC) + return false; + // The source has other uses. See if we can replace the other uses with use of // the result of the extension. SmallPtrSet<MachineBasicBlock*, 4> ReachedBBs; @@ -247,8 +254,10 @@ optimizeExtInstr(MachineInstr *MI, MachineBasicBlock *MBB, continue; // About to add uses of DstReg, clear DstReg's kill flags. - if (!Changed) + if (!Changed) { MRI->clearKillFlags(DstReg); + MRI->constrainRegClass(DstReg, DstRC); + } unsigned NewVR = MRI->createVirtualRegister(RC); BuildMI(*UseMBB, UseMI, UseMI->getDebugLoc(), |