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| author | Geoff Berry <gberry@codeaurora.org> | 2016-11-21 22:51:10 +0000 |
|---|---|---|
| committer | Geoff Berry <gberry@codeaurora.org> | 2016-11-21 22:51:10 +0000 |
| commit | e0bf52f3948dd1b6fdac1d08f1fcadf8211970ab (patch) | |
| tree | ba6362c2ee7656a026a9c6639d75f4aa095315b4 /llvm/lib | |
| parent | 3e50a5be8f5259bc256f39830e72525dd9f90626 (diff) | |
| download | bcm5719-llvm-e0bf52f3948dd1b6fdac1d08f1fcadf8211970ab.tar.gz bcm5719-llvm-e0bf52f3948dd1b6fdac1d08f1fcadf8211970ab.zip | |
[AArch64LoadStoreOptimizer] Don't treat write to XZR/WZR as a clobber.
Summary:
When searching for load/store instructions to pair/merge don't treat
writes to WZR/XZR as clobbers since they don't change the value read
from WZR/XZR (which is always 0).
Reviewers: mcrosier, junbuml, jmolloy, t.p.northover
Subscribers: aemerson, llvm-commits, rengolin
Differential Revision: https://reviews.llvm.org/D26921
llvm-svn: 287592
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp b/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp index 7aed5d65600..6e157638184 100644 --- a/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp +++ b/llvm/lib/Target/AArch64/AArch64LoadStoreOptimizer.cpp @@ -863,8 +863,10 @@ static void trackRegDefsUses(const MachineInstr &MI, BitVector &ModifiedRegs, if (!Reg) continue; if (MO.isDef()) { - for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) - ModifiedRegs.set(*AI); + // WZR/XZR are not modified even when used as a destination register. + if (Reg != AArch64::WZR && Reg != AArch64::XZR) + for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) + ModifiedRegs.set(*AI); } else { assert(MO.isUse() && "Reg operand not a def and not a use?!?"); for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI) |
