diff options
Diffstat (limited to 'llvm/lib/Target')
| -rw-r--r-- | llvm/lib/Target/AArch64/AArch64ConditionOptimizer.cpp | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/llvm/lib/Target/AArch64/AArch64ConditionOptimizer.cpp b/llvm/lib/Target/AArch64/AArch64ConditionOptimizer.cpp index fc27bfee73d..8a3748389a2 100644 --- a/llvm/lib/Target/AArch64/AArch64ConditionOptimizer.cpp +++ b/llvm/lib/Target/AArch64/AArch64ConditionOptimizer.cpp @@ -144,10 +144,18 @@ MachineInstr *AArch64ConditionOptimizer::findSuitableCompare( if (I->getOpcode() != AArch64::Bcc) return nullptr; + // Since we may modify cmp of this MBB, make sure NZCV does not live out. + for (auto SuccBB : MBB->successors()) + if (SuccBB->isLiveIn(AArch64::NZCV)) + return nullptr; + // Now find the instruction controlling the terminator. for (MachineBasicBlock::iterator B = MBB->begin(); I != B;) { --I; assert(!I->isTerminator() && "Spurious terminator"); + // Check if there is any use of NZCV between CMP and Bcc. + if (I->readsRegister(AArch64::NZCV)) + return nullptr; switch (I->getOpcode()) { // cmp is an alias for subs with a dead destination register. case AArch64::SUBSWri: |
