From 3eeba88631db6da7d45df67f677556297bd93f75 Mon Sep 17 00:00:00 2001
From: Pete Cooper <peter_cooper@apple.com>
Date: Fri, 10 Aug 2012 03:26:36 +0000
Subject: [PATCH] Fix crash when when do lto on Bullet.  Dynamic GEPs in SROA
 were incorrectly being applied to all accesses to an alloca, not just the
 ones which read from the GEP.  Thanks to Evan for reducing the test. 
 rdar://11861001

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161654 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../Scalar/ScalarReplAggregates.cpp           | 11 +++++++---
 test/Transforms/ScalarRepl/crash.ll           | 22 +++++++++++++++++++
 2 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index ec835b15ca8..6637126fcb7 100644
--- a/lib/Transforms/Scalar/ScalarReplAggregates.cpp
+++ b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
@@ -612,11 +612,16 @@ void ConvertToScalarInfo::ConvertUsesToScalar(Value *Ptr, AllocaInst *NewAI,
     if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(User)) {
       // Compute the offset that this GEP adds to the pointer.
       SmallVector<Value*, 8> Indices(GEP->op_begin()+1, GEP->op_end());
-      if (!GEP->hasAllConstantIndices())
-        NonConstantIdx = Indices.pop_back_val();
+      Value* GEPNonConstantIdx = 0;
+      if (!GEP->hasAllConstantIndices()) {
+        assert(!NonConstantIdx &&
+               "Dynamic GEP reading from dynamic GEP unsupported");
+        GEPNonConstantIdx = Indices.pop_back_val();
+      } else
+        GEPNonConstantIdx = NonConstantIdx;
       uint64_t GEPOffset = TD.getIndexedOffset(GEP->getPointerOperandType(),
                                                Indices);
-      ConvertUsesToScalar(GEP, NewAI, Offset+GEPOffset*8, NonConstantIdx);
+      ConvertUsesToScalar(GEP, NewAI, Offset+GEPOffset*8, GEPNonConstantIdx);
       GEP->eraseFromParent();
       continue;
     }
diff --git a/test/Transforms/ScalarRepl/crash.ll b/test/Transforms/ScalarRepl/crash.ll
index cd4dc328e69..58c5a3a0527 100644
--- a/test/Transforms/ScalarRepl/crash.ll
+++ b/test/Transforms/ScalarRepl/crash.ll
@@ -260,5 +260,27 @@ entry:
   ret void
 }
 
+; rdar://11861001 - The dynamic GEP here was incorrectly making all accesses
+; to the alloca think they were also dynamic.  Inserts and extracts created to
+; access the vector were all being based from the dynamic access, even in BBs
+; not dominated by the GEP.
+define fastcc void @test() optsize inlinehint ssp align 2 {
+entry:
+  %alloc.0.0 = alloca <4 x float>, align 16
+  %bitcast = bitcast <4 x float>* %alloc.0.0 to [4 x float]*
+  %idx3 = getelementptr inbounds [4 x float]* %bitcast, i32 0, i32 3
+  store float 0.000000e+00, float* %idx3, align 4
+  br label %for.body10
+
+for.body10:                                       ; preds = %for.body10, %entry
+  %loopidx = phi i32 [ 0, %entry ], [ undef, %for.body10 ]
+  %unusedidx = getelementptr inbounds <4 x float>* %alloc.0.0, i32 0, i32 %loopidx
+  br i1 undef, label %for.end, label %for.body10
+
+for.end:                                          ; preds = %for.body10
+  store <4 x float> <float -1.000000e+00, float -1.000000e+00, float -1.000000e+00, float 0.000000e+00>, <4 x float>* %alloc.0.0, align 16
+  ret void
+}
+
 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* nocapture, i8* nocapture, i32, i32, i1) nounwind
 declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) nounwind