Merge 80762 from mainline.

fix PR4848 an infinite loop when indexing down through a recursive gep
and we get the original pointer type.  This doesn't mean that we're
at the first pointer being indexed.  Correct the predicate.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_26@81028 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 25 insertions, 1 deletions

diff --git a/lib/Analysis/ConstantFolding.cpp b/lib/Analysis/ConstantFolding.cpp
index 5dcb021acf6f..109eaad4584e 100644
--- a/lib/Analysis/ConstantFolding.cpp
+++ b/lib/Analysis/ConstantFolding.cpp
@@ -172,7 +172,7 @@ static Constant *SymbolicallyEvaluateGEP(Constant* const* Ops, unsigned NumOps,
   do {
     if (const SequentialType *ATy = dyn_cast<SequentialType>(Ty)) {
       // The only pointer indexing we'll do is on the first index of the GEP.
-      if (isa<PointerType>(ATy) && ATy != Ptr->getType())
+      if (isa<PointerType>(ATy) && !NewIdxs.empty())
         break;
       // Determine which element of the array the offset points into.
       APInt ElemSize(BitWidth, TD->getTypeAllocSize(ATy->getElementType()));
diff --git a/test/Transforms/ConstProp/2009-10-01-GEP-Crash.ll b/test/Transforms/ConstProp/2009-10-01-GEP-Crash.ll
new file mode 100644
index 000000000000..4d51bf6388ab
--- /dev/null
+++ b/test/Transforms/ConstProp/2009-10-01-GEP-Crash.ll
@@ -0,0 +1,24 @@
+; RUN: llvm-as < %s | opt -constprop | llvm-dis
+; PR4848
+target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%0 = type { %struct.anon }
+%1 = type { %0, %2, [24 x i8] }
+%2 = type <{ %3, %3 }>
+%3 = type { %struct.hrtimer_cpu_base*, i32, %struct.rb_root, %struct.rb_node*, %struct.pgprot, i64 ()*, [16 x i8] }
+%struct.anon = type { }
+%struct.hrtimer_clock_base = type { %struct.hrtimer_cpu_base*, i32, %struct.rb_root, %struct.rb_node*, %struct.pgprot, i64 ()*, %struct.pgprot, %struct.pgprot }
+%struct.hrtimer_cpu_base = type { %0, [2 x %struct.hrtimer_clock_base], %struct.pgprot, i32, i64 }
+%struct.pgprot = type { i64 }
+%struct.rb_node = type { i64, %struct.rb_node*, %struct.rb_node* }
+%struct.rb_root = type { %struct.rb_node* }
+
+@per_cpu__hrtimer_bases = external global %1, align 8 ; <%1*> [#uses=1]
+
+define void @init_hrtimers_cpu(i32 %cpu) nounwind noredzone section ".cpuinit.text" {
+entry:
+  %tmp3 = getelementptr %struct.hrtimer_cpu_base* bitcast (%1* @per_cpu__hrtimer_bases to %struct.hrtimer_cpu_base*), i32 0, i32 0 ; <%0*> [#uses=1]
+  %tmp5 = bitcast %0* %tmp3 to i8*                ; <i8*> [#uses=0]
+  unreachable
+}