From: Dan Gohman <gohman@apple.com>
Date: Mon, 22 Jun 2009 00:15:15 +0000 (+0000)
Subject: Fix this code to correctly handle loops with multiple exits. Until
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=03ad6982c458fd6f982079e11c07419bf17efedc;p=oota-llvm.git

Fix this code to correctly handle loops with multiple exits. Until
now, this hasn't mattered, because ScalarEvolution hasn't been able
to compute trip counts for loops with multiple exits. But it will
soon.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73864 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index 429de935369..326fb38909b 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -299,11 +299,11 @@ void IndVarSimplify::RewriteLoopExitValues(Loop *L,
         // If this instruction is dead now, delete it.
         RecursivelyDeleteTriviallyDeadInstructions(Inst);
 
-        // See if this is a single-entry LCSSA PHI node.  If so, we can (and
-        // have to) remove
-        // the PHI entirely.  This is safe, because the NewVal won't be variant
+        // If we're inserting code into the exit block rather than the
+        // preheader, we can (and have to) remove the PHI entirely.
+        // This is safe, because the NewVal won't be variant
         // in the loop, so we don't need an LCSSA phi node anymore.
-        if (NumPreds == 1) {
+        if (ExitBlocks.size() == 1) {
           PN->replaceAllUsesWith(ExitVal);
           RecursivelyDeleteTriviallyDeadInstructions(PN);
           break;