diff options
| author | Evan Cheng <evan.cheng@apple.com> | 2011-01-07 23:50:32 +0000 |
|---|---|---|
| committer | Evan Cheng <evan.cheng@apple.com> | 2011-01-07 23:50:32 +0000 |
| commit | c36b7069b42bece963b7e6adf020353ce990ef76 (patch) | |
| tree | fdbe6e1cede36ae3485403b9165bfdc039056eeb /lib/CodeGen/DeadMachineInstructionElim.cpp | |
| parent | 067a16c974fef473fd3bca1d58db0d50c59882ce (diff) | |
Do not model all INLINEASM instructions as having unmodelled side effects.
Instead encode llvm IR level property "HasSideEffects" in an operand (shared
with IsAlignStack). Added MachineInstrs::hasUnmodeledSideEffects() to check
the operand when the instruction is an INLINEASM.
This allows memory instructions to be moved around INLINEASM instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123044 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/DeadMachineInstructionElim.cpp')
| -rw-r--r-- | lib/CodeGen/DeadMachineInstructionElim.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/lib/CodeGen/DeadMachineInstructionElim.cpp b/lib/CodeGen/DeadMachineInstructionElim.cpp index 786de1b6a0..32040e580b 100644 --- a/lib/CodeGen/DeadMachineInstructionElim.cpp +++ b/lib/CodeGen/DeadMachineInstructionElim.cpp @@ -54,6 +54,12 @@ FunctionPass *llvm::createDeadMachineInstructionElimPass() { } bool DeadMachineInstructionElim::isDead(const MachineInstr *MI) const { + // Technically speaking inline asm without side effects and no defs can still + // be deleted. But there is so much bad inline asm code out there, we should + // let them be. + if (MI->isInlineAsm()) + return false; + // Don't delete instructions with side effects. bool SawStore = false; if (!MI->isSafeToMove(TII, 0, SawStore) && !MI->isPHI()) |