Fix PR7175. Insert copies of a REG_SEQUENCE source if it is used by other REG_SEQUENCE instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103994 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index 2d43fba..fdecc5f 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -134,6 +134,7 @@
/// of the de-ssa process. This replaces sources of REG_SEQUENCE as
/// sub-register references of the register defined by REG_SEQUENCE.
bool EliminateRegSequences();
+
public:
static char ID; // Pass identification, replacement for typeid
TwoAddressInstructionPass() : MachineFunctionPass(&ID) {}
@@ -1216,6 +1217,17 @@
}
}
+static bool HasOtherRegSequenceUses(unsigned Reg, MachineInstr *RegSeq,
+ MachineRegisterInfo *MRI) {
+ for (MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg),
+ UE = MRI->use_end(); UI != UE; ++UI) {
+ MachineInstr *UseMI = &*UI;
+ if (UseMI != RegSeq && UseMI->isRegSequence())
+ return true;
+ }
+ return false;
+}
+
/// EliminateRegSequences - Eliminate REG_SEQUENCE instructions as part
/// of the de-ssa process. This replaces sources of REG_SEQUENCE as
/// sub-register references of the register defined by REG_SEQUENCE. e.g.
@@ -1261,7 +1273,9 @@
if (DefMI->isExtractSubreg())
RealSrcs.push_back(DefMI->getOperand(1).getReg());
- if (!Seen.insert(SrcReg) || MI->getParent() != DefMI->getParent()) {
+ if (!Seen.insert(SrcReg) ||
+ MI->getParent() != DefMI->getParent() ||
+ HasOtherRegSequenceUses(SrcReg, MI, MRI)) {
// REG_SEQUENCE cannot have duplicated operands, add a copy.
// Also add an copy if the source if live-in the block. We don't want
// to end up with a partial-redef of a livein, e.g.