[llvm] r223135 - [SwitchLowering] Handle destinations on multiple phi instructions

[Bruno Cardoso Lopes]

Author: bruno
Date: Tue Dec  2 12:31:53 2014
New Revision: 223135

URL: http://llvm.org/viewvc/llvm-project?rev=223135&view=rev
Log:
[SwitchLowering] Handle destinations on multiple phi instructions

Follow up from r222926. Also handle multiple destinations from merged
cases on multiple and subsequent phi instructions.

rdar://problem/19106978

Modified:
    llvm/trunk/lib/Transforms/Utils/LowerSwitch.cpp
    llvm/trunk/test/Transforms/Util/lowerswitch.ll

Modified: llvm/trunk/lib/Transforms/Utils/LowerSwitch.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/LowerSwitch.cpp?rev=223135&r1=223134&r2=223135&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/LowerSwitch.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/LowerSwitch.cpp Tue Dec  2 12:31:53 2014
@@ -149,6 +149,7 @@ static void fixPhis(BasicBlock *SuccBB,
 
     // Only update the first occurence.
     unsigned Idx = 0, E = PN->getNumIncomingValues();
+    unsigned LocalNumMergedCases = NumMergedCases;
     for (; Idx != E; ++Idx) {
       if (PN->getIncomingBlock(Idx) == OrigBB) {
         PN->setIncomingBlock(Idx, NewBB);
@@ -158,10 +159,10 @@ static void fixPhis(BasicBlock *SuccBB,
 
     // Remove additional occurences coming from condensed cases and keep the
     // number of incoming values equal to the number of branches to SuccBB.
-    for (++Idx; NumMergedCases > 0 && Idx != E; ++Idx)
+    for (++Idx; LocalNumMergedCases > 0 && Idx < E; ++Idx)
       if (PN->getIncomingBlock(Idx) == OrigBB) {
         PN->removeIncomingValue(Idx);
-        NumMergedCases--;
+        LocalNumMergedCases--;
       }
   }
 }

Modified: llvm/trunk/test/Transforms/Util/lowerswitch.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Util/lowerswitch.ll?rev=223135&r1=223134&r2=223135&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/Util/lowerswitch.ll (original)
+++ llvm/trunk/test/Transforms/Util/lowerswitch.ll Tue Dec  2 12:31:53 2014
@@ -45,6 +45,8 @@ bb3:
 ; CHECK-LABEL: bb3
 ; CHECK: %tmp = phi i32 [ 1, %NodeBlock ], [ 0, %bb2 ], [ 1, %LeafBlock3 ]
   %tmp = phi i32 [ 1, %bb1 ], [ 0, %bb2 ], [ 1, %bb1 ], [ 1, %bb1 ]
+; CHECK-NEXT: %tmp2 = phi i32 [ 2, %NodeBlock ], [ 5, %bb2 ], [ 2, %LeafBlock3 ]
+  %tmp2 = phi i32 [ 2, %bb1 ], [ 2, %bb1 ], [ 5, %bb2 ], [ 2, %bb1 ]
   br label %exit
 
 exit: