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| author | Ahmed Bougacha <ahmed.bougacha@gmail.com> | 2017-03-21 23:42:54 +0000 |
|---|---|---|
| committer | Ahmed Bougacha <ahmed.bougacha@gmail.com> | 2017-03-21 23:42:54 +0000 |
| commit | 15b3e8a93a4040238f4f7655a7b23a2f50716af8 (patch) | |
| tree | 82040291134652063d1f85b414ac62acb61e3f14 /llvm/lib/CodeGen/GlobalISel/Utils.cpp | |
| parent | e8e1fa3a7cf8a9500a39702cce71cde8aa2960f0 (diff) | |
| download | bcm5719-llvm-15b3e8a93a4040238f4f7655a7b23a2f50716af8.tar.gz bcm5719-llvm-15b3e8a93a4040238f4f7655a7b23a2f50716af8.zip | |
[GlobalISel] Update DBG_VALUEs referencing DCE'd instructions.
Quentin points out that r298358 would cause us to emit different code
with debug info. That's a big no-no; also erase the instructions that
only live thanks to DBG_VALUE users.
Adrian explained how this is an existing problem and an OK thing to do:
clang has allocas for all variables so shouldn't be affected at -O0, but
swift uses a bit of inlineasm to explicitly keep values live for the
purpose of debug info quality. I'm not sure there is a better scheme.
llvm-svn: 298460
Diffstat (limited to 'llvm/lib/CodeGen/GlobalISel/Utils.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/GlobalISel/Utils.cpp | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/llvm/lib/CodeGen/GlobalISel/Utils.cpp b/llvm/lib/CodeGen/GlobalISel/Utils.cpp index 2e2f519ab2b..606a59680a3 100644 --- a/llvm/lib/CodeGen/GlobalISel/Utils.cpp +++ b/llvm/lib/CodeGen/GlobalISel/Utils.cpp @@ -61,8 +61,8 @@ bool llvm::isTriviallyDead(const MachineInstr &MI, continue; unsigned Reg = MO.getReg(); - // Keep Debug uses live: we don't want to have an effect on debug info. - if (TargetRegisterInfo::isPhysicalRegister(Reg) || !MRI.use_empty(Reg)) + if (TargetRegisterInfo::isPhysicalRegister(Reg) || + !MRI.use_nodbg_empty(Reg)) return false; } return true; |
