diff options
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/ImplicitNullChecks.cpp | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/llvm/lib/CodeGen/ImplicitNullChecks.cpp b/llvm/lib/CodeGen/ImplicitNullChecks.cpp index 6c35aaac7d2..31d65e69844 100644 --- a/llvm/lib/CodeGen/ImplicitNullChecks.cpp +++ b/llvm/lib/CodeGen/ImplicitNullChecks.cpp @@ -268,7 +268,25 @@ bool HazardDetector::isSafeToHoist(MachineInstr *MI, return false; assert((!MO.isDef() || RegDefs.count(MO.getReg())) && "All defs must be tracked in RegDefs by now!"); - return !MO.isDef() || RegDefs.find(MO.getReg())->second == MI; + + if (!MO.isDef()) { + // FIXME: This is unnecessary, we should be able to + // assert(MO.isDef()) here. + return true; + } + + for (unsigned Reg : RegUses) + if (TRI.regsOverlap(Reg, MO.getReg())) + return false; // We found a write-after-read + + for (auto &OtherDef : RegDefs) { + unsigned OtherReg = OtherDef.first; + MachineInstr *OtherMI = OtherDef.second; + if (OtherMI != MI && TRI.regsOverlap(OtherReg, MO.getReg())) + return false; + } + + return true; }; if (!all_of(MI->operands(), IsMIOperandSafe)) |
