[llvm] r268805 - LiveIntervalAnalysis: Fix handleMove() extending liverange for undef inputs

[Matthias Braun via llvm-commits]

Author: matze
Date: Fri May  6 16:47:41 2016
New Revision: 268805

URL: http://llvm.org/viewvc/llvm-project?rev=268805&view=rev
Log:
LiveIntervalAnalysis: Fix handleMove() extending liverange for undef inputs

Fix handleMove() incorrectly extending liveranges when an undef input of
a vreg was moved past the (current) end of the liverange.

Modified:
    llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
    llvm/trunk/unittests/MI/LiveIntervalTest.cpp

Modified: llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp?rev=268805&r1=268804&r2=268805&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp Fri May  6 16:47:41 2016
@@ -939,10 +939,13 @@ public:
         hasRegMask = true;
       if (!MO.isReg())
         continue;
-      // Aggressively clear all kill flags.
-      // They are reinserted by VirtRegRewriter.
-      if (MO.isUse())
+      if (MO.isUse()) {
+        if (!MO.readsReg())
+          continue;
+        // Aggressively clear all kill flags.
+        // They are reinserted by VirtRegRewriter.
         MO.setIsKill(false);
+      }
 
       unsigned Reg = MO.getReg();
       if (!Reg)

Modified: llvm/trunk/unittests/MI/LiveIntervalTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/MI/LiveIntervalTest.cpp?rev=268805&r1=268804&r2=268805&view=diff
==============================================================================
--- llvm/trunk/unittests/MI/LiveIntervalTest.cpp (original)
+++ llvm/trunk/unittests/MI/LiveIntervalTest.cpp Fri May  6 16:47:41 2016
@@ -300,6 +300,17 @@ TEST(LiveIntervalTest, MoveDownKillFollo
   });
 }
 
+TEST(LiveIntervalTest, MoveUndefUse) {
+  liveIntervalTest(
+"    %0 = IMPLICIT_DEF\n"
+"    NOOP implicit undef %0\n"
+"    NOOP implicit %0\n"
+"    NOOP\n",
+  [](MachineFunction &MF, LiveIntervals &LIS) {
+    testHandleMove(MF, LIS, 1, 3);
+  });
+}
+
 int main(int argc, char **argv) {
   ::testing::InitGoogleTest(&argc, argv);
   initLLVM();