Fix PR2138. Apparently any modification to a std::multimap (including remove entries for a different key) can invalidate multimap iterators.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48371 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/VirtRegMap.cpp b/lib/CodeGen/VirtRegMap.cpp
index 8c6934a..b094412 100644
--- a/lib/CodeGen/VirtRegMap.cpp
+++ b/lib/CodeGen/VirtRegMap.cpp
@@ -865,12 +865,15 @@
unsigned UnfoldVR = 0;
int FoldedSS = VirtRegMap::NO_STACK_SLOT;
VirtRegMap::MI2VirtMapTy::const_iterator I, End;
- for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ++I) {
+ for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ) {
// Only transform a MI that folds a single register.
if (UnfoldedOpc)
return false;
UnfoldVR = I->second.first;
VirtRegMap::ModRef MR = I->second.second;
+ // MI2VirtMap be can updated which invalidate the iterator.
+ // Increment the iterator first.
+ ++I;
if (VRM.isAssignedReg(UnfoldVR))
continue;
// If this reference is not a use, any previous store is now dead.
@@ -1380,11 +1383,14 @@
// physical registers that may contain the value of the spilled virtual
// register
SmallSet<int, 2> FoldedSS;
- for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ++I) {
+ for (tie(I, End) = VRM.getFoldedVirts(&MI); I != End; ) {
unsigned VirtReg = I->second.first;
VirtRegMap::ModRef MR = I->second.second;
DOUT << "Folded vreg: " << VirtReg << " MR: " << MR;
+ // MI2VirtMap be can updated which invalidate the iterator.
+ // Increment the iterator first.
+ ++I;
int SS = VRM.getStackSlot(VirtReg);
if (SS == VirtRegMap::NO_STACK_SLOT)
continue;