From c2d1b6949c5141d21827cc94daea6ae4b1a9c750 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sat, 9 Jan 2010 06:01:36 +0000
Subject: [PATCH] only factor from expressions whose uses are empty and whose
 base is the right expression type.  This fixes PR5981.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93045 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/Reassociate.cpp |  5 +++++
 test/Transforms/Reassociate/crash.ll  | 20 +++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/lib/Transforms/Scalar/Reassociate.cpp b/lib/Transforms/Scalar/Reassociate.cpp
index 3cc380a0e4b..4a99f4a844e 100644
--- a/lib/Transforms/Scalar/Reassociate.cpp
+++ b/lib/Transforms/Scalar/Reassociate.cpp
@@ -792,6 +792,11 @@ Value *Reassociate::OptimizeAdd(Instruction *I,
     Instruction *DummyInst = BinaryOperator::CreateAdd(MaxOccVal, MaxOccVal);
     SmallVector<Value*, 4> NewMulOps;
     for (unsigned i = 0, e = Ops.size(); i != e; ++i) {
+      // Only try to remove factors from expressions we're allowed to.
+      BinaryOperator *BOp = dyn_cast<BinaryOperator>(Ops[i].Op);
+      if (BOp == 0 || BOp->getOpcode() != Instruction::Mul || !BOp->use_empty())
+        continue;
+      
       if (Value *V = RemoveFactorFromExpression(Ops[i].Op, MaxOccVal)) {
         NewMulOps.push_back(V);
         Ops.erase(Ops.begin()+i);
diff --git a/test/Transforms/Reassociate/crash.ll b/test/Transforms/Reassociate/crash.ll
index 12f8a376fdb..060018d8da4 100644
--- a/test/Transforms/Reassociate/crash.ll
+++ b/test/Transforms/Reassociate/crash.ll
@@ -2,7 +2,7 @@
 
 
 ; rdar://7507855
-define fastcc i32 @test() nounwind {
+define fastcc i32 @test1() nounwind {
 entry:
   %cond = select i1 undef, i32 1, i32 -1          ; <i32> [#uses=2]
   br label %for.cond
@@ -13,3 +13,21 @@ for.cond:                                         ; preds = %for.body, %entry
   %add896 = sub i32 0, %cond                      ; <i32> [#uses=0]
   ret i32 undef
 }
+
+; PR5981
+define i32 @test2() nounwind ssp {
+entry:
+  %0 = load i32* undef, align 4
+  %1 = mul nsw i32 undef, %0
+  %2 = mul nsw i32 undef, %0
+  %3 = add nsw i32 undef, %1
+  %4 = add nsw i32 %3, %2
+  %5 = add nsw i32 %4, 4
+  %6 = shl i32 %0, 3                              ; <i32> [#uses=1]
+  %7 = add nsw i32 %5, %6
+  br label %bb4.i9
+
+bb4.i9:                                           ; preds = %bb3.i7, %bb1.i25.i
+  %8 = add nsw i32 undef, %1
+  ret i32 0
+}