[llvm-commits] CVS: llvm/lib/CodeGen/LiveIntervals.cpp

[Alkis Evlogimenos]

Changes in directory llvm/lib/CodeGen:

LiveIntervals.cpp updated: 1.31 -> 1.32

---
Log message:

Fix failing test cases with joined live intervals. It turns out that
when joining we need to check if we overlap with the second interval
or any of its aliases.

Also make joining intervals the default.


---
Diffs of the changes:  (+24 -3)

Index: llvm/lib/CodeGen/LiveIntervals.cpp
diff -u llvm/lib/CodeGen/LiveIntervals.cpp:1.31 llvm/lib/CodeGen/LiveIntervals.cpp:1.32
--- llvm/lib/CodeGen/LiveIntervals.cpp:1.31	Thu Jan 22 17:08:44 2004
+++ llvm/lib/CodeGen/LiveIntervals.cpp	Fri Jan 23 07:37:51 2004
@@ -49,7 +49,7 @@
     cl::opt<bool>
     join("join-liveintervals",
          cl::desc("Join compatible live intervals"),
-         cl::init(false));
+         cl::init(true));
 };
 
 void LiveIntervals::getAnalysisUsage(AnalysisUsage &AU) const
@@ -387,26 +387,31 @@
                 Intervals::iterator srcInt = r2iSrc->second;
                 Intervals::iterator dstInt = r2iDst->second;
 
+                // src is a physical register
                 if (srcInt->reg < MRegisterInfo::FirstVirtualRegister) {
                     if (dstInt->reg == srcInt->reg ||
                         (dstInt->reg >= MRegisterInfo::FirstVirtualRegister &&
-                         !dstInt->overlaps(*srcInt))) {
+                         !srcInt->overlaps(*dstInt) &&
+                         !overlapsAliases(*srcInt, *dstInt))) {
                         srcInt->join(*dstInt);
                         r2iDst->second = r2iSrc->second;
                         r2rMap_.insert(std::make_pair(dstInt->reg, srcInt->reg));
                         intervals_.erase(dstInt);
                     }
                 }
+                // dst is a physical register
                 else if (dstInt->reg < MRegisterInfo::FirstVirtualRegister) {
                     if (srcInt->reg == dstInt->reg ||
                         (srcInt->reg >= MRegisterInfo::FirstVirtualRegister &&
-                         !srcInt->overlaps(*dstInt))) {
+                         !dstInt->overlaps(*srcInt) &&
+                         !overlapsAliases(*dstInt, *srcInt))) {
                         dstInt->join(*srcInt);
                         r2iSrc->second = r2iDst->second;
                         r2rMap_.insert(std::make_pair(srcInt->reg, dstInt->reg));
                         intervals_.erase(srcInt);
                     }
                 }
+                // neither src nor dst are physical registers
                 else {
                     const TargetRegisterClass *srcRc, *dstRc;
                     srcRc = mf_->getSSARegMap()->getRegClass(srcInt->reg);
@@ -430,6 +435,22 @@
                    e = r2rMap_.end(); i != e; ++i)
           std::cerr << i->first << " -> " << i->second << '\n';);
                
+}
+
+bool LiveIntervals::overlapsAliases(const Interval& lhs,
+                                    const Interval& rhs) const
+{
+    assert(lhs.reg < MRegisterInfo::FirstVirtualRegister &&
+           "first interval must describe a physical register");
+
+    for (const unsigned* as = mri_->getAliasSet(lhs.reg); *as; ++as) {
+        Reg2IntervalMap::const_iterator r2i = r2iMap_.find(*as);
+        assert(r2i != r2iMap_.end() && "alias does not have interval?");
+        if (rhs.overlaps(*r2i->second))
+            return true;
+    }
+
+    return false;
 }
 
 LiveIntervals::Interval::Interval(unsigned r)