[llvm-commits] [llvm] r44443 - /llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp

[Evan Cheng]

Author: evancheng
Date: Thu Nov 29 17:02:50 2007
New Revision: 44443

URL: http://llvm.org/viewvc/llvm-project?rev=44443&view=rev
Log:
Do not lose rematerialization info when spilling already split live intervals.

Modified:
    llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp

Modified: llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
URL: 
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp?rev=44443&r1=44442&r2=44443&view=diff

==============================================================================
--- llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp Thu Nov 29 17:02:50 2007
@@ -720,7 +720,7 @@
       continue;
 
     bool TryFold = !DefIsReMat;
-    bool FoldSS = true;
+    bool FoldSS = true; // Default behavior unless it's a remat.
     int FoldSlot = Slot;
     if (DefIsReMat) {
       // If this is the rematerializable definition MI itself and
@@ -734,8 +734,7 @@
 
       // If def for this use can't be rematerialized, then try folding.
       // If def is rematerializable and it's a load, also try folding.
-      TryFold = !ReMatOrigDefMI ||
-        (ReMatOrigDefMI && (MI == ReMatOrigDefMI || isLoad));
+      TryFold = !ReMatDefMI || (ReMatDefMI && (MI == ReMatOrigDefMI || 
isLoad));
       if (isLoad) {
         // Try fold loads (from stack slot, constant pool, etc.) into uses.
         FoldSS = isLoadSS;
@@ -810,6 +809,12 @@
       } else {
         vrm.assignVirt2StackSlot(NewVReg, Slot);
       }
+    } else if (HasUse && HasDef &&
+               vrm.getStackSlot(NewVReg) == VirtRegMap::NO_STACK_SLOT) {
+      // If this interval hasn't been assigned a stack slot (because earlier
+      // def is a deleted remat def), do it now.
+      assert(Slot != VirtRegMap::NO_STACK_SLOT);
+      vrm.assignVirt2StackSlot(NewVReg, Slot);
     }
 
     // create a new register interval for this spill / remat.
@@ -984,17 +989,6 @@
           SpillMBBs.set(MBBId);
         }
       }
-
-      /// FIXME: Move this else where.
-      if (!IsNew) {
-        // It this interval hasn't been assigned a stack slot
-        // (because earlier def is remat), do it now.
-        int SS = vrm.getStackSlot(NewVReg);
-        if (SS != (int)Slot) {
-          assert(SS == VirtRegMap::NO_STACK_SLOT);
-          vrm.assignVirt2StackSlot(NewVReg, Slot);
-        }
-      }
     }
 
     if (HasUse) {
@@ -1110,6 +1104,7 @@
       // are two-address instructions that re-defined the value. Only the
       // first def can be rematerialized!
       if (IsFirstRange) {
+        // Note ReMatOrigDefMI has already been deleted.
         rewriteInstructionsForSpills(li, false, I, NULL, ReMatDefMI,
                              Slot, LdSlot, isLoad, isLoadSS, DefIsReMat,
                              false, vrm, RegMap, rc, ReMatIds, loopInfo,


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