Special-case static allocas in IndVarSimplify's loop invariant

sinking code, since they are special. If the loop preheader happens
to be the entry block of a function, don't sink static allocas
out of it. This fixes PR4775.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80010 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 0 deletions

diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index 790a4fc51d..ceca45220e 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -553,6 +553,11 @@ void IndVarSimplify::SinkUnusedInvariants(Loop *L) {
     // dominates the exit block.
     if (I->mayHaveSideEffects() || I->mayReadFromMemory())
       continue;
+    // Don't sink static AllocaInsts out of the entry block, which would
+    // turn them into dynamic allocas!
+    if (AllocaInst *AI = dyn_cast<AllocaInst>(I))
+      if (AI->isStaticAlloca())
+        continue;
     // Determine if there is a use in or before the loop (direct or
     // otherwise).
     bool UsedInLoop = false;