LiveIntervalAnalysis: Rework constructMainRangeFromSubranges()
We now use LiveRangeCalc::extendToUses() instead of a specially designed
algorithm in constructMainRangeFromSubranges():
- The original motivation for constructMainRangeFromSubranges() were
differences between the main liverange and subranges because of hidden
dead definitions. This case however cannot happen anymore with the
DetectDeadLaneMasks pass in place.
- It simplifies the code.
- This fixes a longstanding bug where we did not properly create new SSA
values on merging control flow (the MachineVerifier missed most of
these cases).
- Move constructMainRangeFromSubranges() to LiveIntervalAnalysis and
LiveRangeCalc to better match the implementation/available helper
functions.
This re-applies r269016. The fixes from r270290 and r270259 should avoid
the machine verifier problems this time.
llvm-svn: 270291
diff --git a/llvm/lib/CodeGen/LiveRangeCalc.cpp b/llvm/lib/CodeGen/LiveRangeCalc.cpp
index 4a0a510..db91ca113 100644
--- a/llvm/lib/CodeGen/LiveRangeCalc.cpp
+++ b/llvm/lib/CodeGen/LiveRangeCalc.cpp
@@ -120,13 +120,29 @@
extendToUses(S, Reg, S.LaneMask);
}
LI.clear();
- LI.constructMainRangeFromSubranges(*Indexes, *Alloc);
+ constructMainRangeFromSubranges(LI);
} else {
resetLiveOutMap();
extendToUses(LI, Reg, ~0u);
}
}
+void LiveRangeCalc::constructMainRangeFromSubranges(LiveInterval &LI) {
+ // First create dead defs at all defs found in subranges.
+ LiveRange &MainRange = LI;
+ assert(MainRange.segments.empty() && MainRange.valnos.empty() &&
+ "Expect empty main liverange");
+
+ for (const LiveInterval::SubRange &SR : LI.subranges()) {
+ for (const VNInfo *VNI : SR.valnos) {
+ if (!VNI->isUnused() && !VNI->isPHIDef())
+ MainRange.createDeadDef(VNI->def, *Alloc);
+ }
+ }
+
+ resetLiveOutMap();
+ extendToUses(MainRange, LI.reg);
+}
void LiveRangeCalc::createDeadDefs(LiveRange &LR, unsigned Reg) {
assert(MRI && Indexes && "call reset() first");