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

2 files changed, 30 insertions, 3 deletions

diff --git a/lib/Transforms/Scalar/ScalarReplAggregates.cpp b/lib/Transforms/Scalar/ScalarReplAggregates.cpp
index ec835b15ca..6637126fcb 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 cd4dc328e6..58c5a3a052 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