Add incoming value from header only if phi node has any use inside the loop.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@48738 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/LoopIndexSplit.cpp b/lib/Transforms/Scalar/LoopIndexSplit.cpp
index 3aedb93..513cad8 100644 (file)
--- a/lib/Transforms/Scalar/LoopIndexSplit.cpp
+++ b/lib/Transforms/Scalar/LoopIndexSplit.cpp
@@ -1665,8 +1665,9 @@ void LoopIndexSplit::updatePHINodes(BasicBlock *ExitBB, BasicBlock *Latch,
             break;
           }
 
-      assert (NewV && "Unable to find new incoming value for exit block PHI");
-      PN->addIncoming(NewV, Header);
+      // Add incoming value from header only if PN has any use inside the loop.
+      if (NewV)
+        PN->addIncoming(NewV, Header);
 
     } else if (Instruction *PHI = dyn_cast<Instruction>(V)) {
       // If this instruction is IVIncrement then IV is new incoming value 

diff --git a/test/Transforms/LoopIndexSplit/2008-03-24-ExitPhi.ll b/test/Transforms/LoopIndexSplit/2008-03-24-ExitPhi.ll
new file mode 100644 (file)
index 0000000..24f22ca
--- /dev/null
+++ b/test/Transforms/LoopIndexSplit/2008-03-24-ExitPhi.ll
@@ -0,0 +1,69 @@
+; RUN: llvm-as < %s | opt -loop-index-split -disable-output
+; Handle Exit block phis that do not have any use inside the loop.
+
+       %struct.ATOM = type { double, double, double, double, double, double, i32, double, double, double, double, i8*, i8, [9 x i8], double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, double, [200 x i8*], [32 x i8*], [32 x i8], i32 }
+       %struct.FILE = type { i8*, i32, i32, i16, i16, %struct.__sbuf, i32, i8*, i32 (i8*)*, i32 (i8*, i8*, i32)*, i64 (i8*, i64, i32)*, i32 (i8*, i8*, i32)*, %struct.__sbuf, %struct.__sFILEX*, i32, [3 x i8], [1 x i8], %struct.__sbuf, i32, i64 }
+       %struct.__sFILEX = type opaque
+       %struct.__sbuf = type { i8*, i32 }
+
+define i32 @math([80 x i8]* %tokens, double* %fvalue, i32* %ivalue, %struct.FILE* %ip, %struct.FILE* %op, i32 %echo) nounwind  {
+entry:
+       br i1 false, label %bb.i, label %bb35.i
+bb.i:          ; preds = %entry
+       br i1 false, label %bb6.i, label %bb9.i
+bb9.i:         ; preds = %bb.i
+       ret i32 0
+bb35.i:                ; preds = %entry
+       ret i32 0
+bb6.i:         ; preds = %bb.i
+       br i1 false, label %a_l2_f.exit, label %bb16.i
+bb16.i:                ; preds = %bb6.i
+       ret i32 0
+a_l2_f.exit:           ; preds = %bb6.i
+       br i1 false, label %bb7.i97, label %bb6.i71
+bb6.i71:               ; preds = %a_l2_f.exit
+       ret i32 0
+bb7.i97:               ; preds = %a_l2_f.exit
+       br i1 false, label %bb, label %bb18.i102
+bb18.i102:             ; preds = %bb7.i97
+       ret i32 0
+bb:            ; preds = %bb7.i97
+       br i1 false, label %bb38, label %AFOUND
+bb38:          ; preds = %bb
+       br i1 false, label %bb111, label %bb7.i120
+AFOUND:                ; preds = %bb
+       ret i32 0
+bb7.i120:              ; preds = %bb38
+       ret i32 0
+bb111:         ; preds = %bb38
+       switch i32 0, label %bb574 [
+                i32 1, label %bb158
+                i32 0, label %bb166
+       ]
+bb158:         ; preds = %bb111
+       ret i32 0
+bb166:         ; preds = %bb111
+       ret i32 0
+bb574:         ; preds = %bb111
+       br i1 false, label %bb11.i249, label %bb600
+bb11.i249:             ; preds = %bb574
+       br i1 false, label %bb11.i265, label %bb596
+bb11.i265:             ; preds = %bb590, %bb11.i249
+       %i.1.reg2mem.0 = phi i32 [ %tmp589.reg2mem.0, %bb590 ], [ 0, %bb11.i249 ]               ; <i32> [#uses=2]
+       %tmp13.i264 = icmp slt i32 %i.1.reg2mem.0, 1            ; <i1> [#uses=1]
+       br i1 %tmp13.i264, label %bb16.i267, label %bb30.i279
+bb16.i267:             ; preds = %bb11.i265
+       br label %bb590
+bb30.i279:             ; preds = %bb11.i265
+       br label %bb590
+bb590:         ; preds = %bb30.i279, %bb16.i267
+       %tmp5876282.reg2mem.0 = phi %struct.ATOM* [ null, %bb30.i279 ], [ null, %bb16.i267 ]            ; <%struct.ATOM*> [#uses=1]
+       %tmp589.reg2mem.0 = add i32 %i.1.reg2mem.0, 1           ; <i32> [#uses=2]
+       %tmp593 = icmp slt i32 %tmp589.reg2mem.0, 0             ; <i1> [#uses=1]
+       br i1 %tmp593, label %bb11.i265, label %bb596
+bb596:         ; preds = %bb590, %bb11.i249
+       %ap.0.reg2mem.0 = phi %struct.ATOM* [ null, %bb11.i249 ], [ %tmp5876282.reg2mem.0, %bb590 ]             ; <%struct.ATOM*> [#uses=0]
+       ret i32 0
+bb600:         ; preds = %bb574
+       ret i32 0
+}