[llvm-commits] [llvm] r46898 - in /llvm/trunk: lib/Transforms/Scalar/LoopIndexSplit.cpp test/Transforms/LoopIndexSplit/2008-02-08-Crash.ll

[Devang Patel]

Author: dpatel
Date: Fri Feb  8 16:49:13 2008
New Revision: 46898

URL: http://llvm.org/viewvc/llvm-project?rev=46898&view=rev
Log:
Fix PR 1995.


Added:
    llvm/trunk/test/Transforms/LoopIndexSplit/2008-02-08-Crash.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/LoopIndexSplit.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/LoopIndexSplit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/LoopIndexSplit.cpp?rev=46898&r1=46897&r2=46898&view=diff

==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/LoopIndexSplit.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/LoopIndexSplit.cpp Fri Feb  8 16:49:13 2008
@@ -1392,6 +1392,11 @@
   if (!Succ0->getSinglePredecessor() || !Succ1->getSinglePredecessor())
     return false;
 
+  // If Exiting block includes loop variant instructions then this
+  // loop may not be split safely.
+  if (!safeExitingBlock(SD, ExitCondition->getParent())) 
+    return false;
+
   // After loop is cloned there are two loops.
   //
   // First loop, referred as ALoop, executes first part of loop's iteration
@@ -1616,8 +1621,8 @@
 ///   - ExitBB's single predecessor was Latch
 ///   - Latch's second successor was Header
 /// Now
-///   - ExitBB's single predecessor was Header
-///   - Latch's one and only successor was Header
+///   - ExitBB's single predecessor is Header
+///   - Latch's one and only successor is Header
 ///
 /// Update ExitBB PHINodes' to reflect this change.
 void LoopIndexSplit::updatePHINodes(BasicBlock *ExitBB, BasicBlock *Latch, 
@@ -1632,27 +1637,18 @@
 
     Value *V = PN->getIncomingValueForBlock(Latch);
     if (PHINode *PHV = dyn_cast<PHINode>(V)) {
-      // PHV is in Latch. PHV has two uses, one use is in ExitBB PHINode 
-      // (i.e. PN :)). 
-      // The second use is in Header and it is new incoming value for PN.
-      PHINode *U1 = NULL;
-      PHINode *U2 = NULL;
+      // PHV is in Latch. PHV has one use is in ExitBB PHINode. And one use
+      // in Header which is new incoming value for PN.
       Value *NewV = NULL;
       for (Value::use_iterator UI = PHV->use_begin(), E = PHV->use_end(); 
-           UI != E; ++UI) {
-        if (!U1)
-          U1 = cast<PHINode>(*UI);
-        else if (!U2)
-          U2 = cast<PHINode>(*UI);
-        else
-          assert ( 0 && "Unexpected third use of this PHINode");
-      }
-      assert (U1 && U2 && "Unable to find two uses");
-      
-      if (U1->getParent() == Header) 
-        NewV = U1;
-      else
-        NewV = U2;
+           UI != E; ++UI) 
+        if (PHINode *U = dyn_cast<PHINode>(*UI)) 
+          if (U->getParent() == Header) {
+            NewV = U;
+            break;
+          }
+
+      assert (NewV && "Unable to find new incoming value for exit block PHI");
       PN->addIncoming(NewV, Header);
 
     } else if (Instruction *PHI = dyn_cast<Instruction>(V)) {

Added: llvm/trunk/test/Transforms/LoopIndexSplit/2008-02-08-Crash.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/LoopIndexSplit/2008-02-08-Crash.ll?rev=46898&view=auto

==============================================================================
--- llvm/trunk/test/Transforms/LoopIndexSplit/2008-02-08-Crash.ll (added)
+++ llvm/trunk/test/Transforms/LoopIndexSplit/2008-02-08-Crash.ll Fri Feb  8 16:49:13 2008
@@ -0,0 +1,48 @@
+; RUN: llvm-as < %s | opt -loop-index-split -disable-output
+; PR 1995
+
+define void @add_blkdev_randomness(i32 %major) nounwind  {
+entry:
+	br label %bb
+
+bb:		; preds = %bb39, %entry
+	%A.0.reg2mem.0 = phi i32 [ undef, %entry ], [ %TEMP.0, %bb39 ]		; <i32> [#uses=1]
+	%D.0.reg2mem.0 = phi i32 [ undef, %entry ], [ %C.0.reg2mem.0, %bb39 ]		; <i32> [#uses=3]
+	%C.0.reg2mem.0 = phi i32 [ undef, %entry ], [ %tmp34, %bb39 ]		; <i32> [#uses=4]
+	%TEMP.1.reg2mem.0 = phi i32 [ undef, %entry ], [ %TEMP.0, %bb39 ]		; <i32> [#uses=1]
+	%i.0.reg2mem.0 = phi i32 [ 0, %entry ], [ %tmp38, %bb39 ]		; <i32> [#uses=3]
+	%B.0.reg2mem.0 = phi i32 [ undef, %entry ], [ %A.0.reg2mem.0, %bb39 ]		; <i32> [#uses=5]
+	%tmp1 = icmp slt i32 %i.0.reg2mem.0, 40		; <i1> [#uses=1]
+	br i1 %tmp1, label %bb3, label %bb12
+
+bb3:		; preds = %bb
+	%tmp6 = xor i32 %C.0.reg2mem.0, %D.0.reg2mem.0		; <i32> [#uses=1]
+	%tmp8 = and i32 %B.0.reg2mem.0, %tmp6		; <i32> [#uses=1]
+	%tmp10 = xor i32 %tmp8, %D.0.reg2mem.0		; <i32> [#uses=1]
+	%tmp11 = add i32 %tmp10, 1518500249		; <i32> [#uses=1]
+	br label %bb39
+
+bb12:		; preds = %bb
+	%tmp14 = icmp slt i32 %i.0.reg2mem.0, 60		; <i1> [#uses=1]
+	br i1 %tmp14, label %bb17, label %bb39
+
+bb17:		; preds = %bb12
+	%tmp20 = and i32 %B.0.reg2mem.0, %C.0.reg2mem.0		; <i32> [#uses=1]
+	%tmp23 = xor i32 %B.0.reg2mem.0, %C.0.reg2mem.0		; <i32> [#uses=1]
+	%tmp25 = and i32 %tmp23, %D.0.reg2mem.0		; <i32> [#uses=1]
+	%tmp26 = add i32 %tmp20, -1894007588		; <i32> [#uses=1]
+	%tmp27 = add i32 %tmp26, %tmp25		; <i32> [#uses=1]
+	br label %bb39
+
+bb39:		; preds = %bb12, %bb3, %bb17
+	%TEMP.0 = phi i32 [ %tmp27, %bb17 ], [ %tmp11, %bb3 ], [ %TEMP.1.reg2mem.0, %bb12 ]		; <i32> [#uses=2]
+	%tmp31 = lshr i32 %B.0.reg2mem.0, 2		; <i32> [#uses=1]
+	%tmp33 = shl i32 %B.0.reg2mem.0, 30		; <i32> [#uses=1]
+	%tmp34 = or i32 %tmp31, %tmp33		; <i32> [#uses=1]
+	%tmp38 = add i32 %i.0.reg2mem.0, 1		; <i32> [#uses=2]
+	%tmp41 = icmp slt i32 %tmp38, 80		; <i1> [#uses=1]
+	br i1 %tmp41, label %bb, label %return
+
+return:		; preds = %bb39
+	ret void
+}
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