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| author | Jonas Paulsson <paulsson@linux.vnet.ibm.com> | 2017-05-12 06:32:03 +0000 |
|---|---|---|
| committer | Jonas Paulsson <paulsson@linux.vnet.ibm.com> | 2017-05-12 06:32:03 +0000 |
| commit | d1ec738502b24454f98bee9cd1206aa2854a4eb8 (patch) | |
| tree | 48d47e8f158e32ac9a1bb5436279ca51ecfe5576 /llvm/lib | |
| parent | ce3ec4519b602cf5a58a379b6a3b8471690403a5 (diff) | |
| download | bcm5719-llvm-d1ec738502b24454f98bee9cd1206aa2854a4eb8.tar.gz bcm5719-llvm-d1ec738502b24454f98bee9cd1206aa2854a4eb8.zip | |
Handle a COPY with undef source operand in LowerCopy()
Llvm-stress discovered that a COPY may end up in ExpandPostRA::LowerCopy()
with an undef source operand. It is not possible for the target to handle
this, as this flag is not passed to TII->copyPhysReg().
This patch solves this by treating such a COPY as an identity COPY.
Review: Matthias Braun
https://reviews.llvm.org/D32892
llvm-svn: 302877
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/CodeGen/ExpandPostRAPseudos.cpp | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/llvm/lib/CodeGen/ExpandPostRAPseudos.cpp b/llvm/lib/CodeGen/ExpandPostRAPseudos.cpp index ab2382e2db6..e860906043d 100644 --- a/llvm/lib/CodeGen/ExpandPostRAPseudos.cpp +++ b/llvm/lib/CodeGen/ExpandPostRAPseudos.cpp @@ -142,8 +142,9 @@ bool ExpandPostRA::LowerCopy(MachineInstr *MI) { MachineOperand &DstMO = MI->getOperand(0); MachineOperand &SrcMO = MI->getOperand(1); - if (SrcMO.getReg() == DstMO.getReg()) { - DEBUG(dbgs() << "identity copy: " << *MI); + bool IdentityCopy = (SrcMO.getReg() == DstMO.getReg()); + if (IdentityCopy || SrcMO.isUndef()) { + DEBUG(dbgs() << (IdentityCopy ? "identity copy: " : "undef copy: ") << *MI); // No need to insert an identity copy instruction, but replace with a KILL // if liveness is changed. if (SrcMO.isUndef() || MI->getNumOperands() > 2) { |
