[llvm-commits] [llvm] r98359 - in /llvm/trunk: lib/Analysis/ConstantFolding.cpp test/Transforms/InstCombine/gepgep.ll

[Duncan Sands]

Author: baldrick
Date: Fri Mar 12 11:55:20 2010
New Revision: 98359

URL: http://llvm.org/viewvc/llvm-project?rev=98359&view=rev
Log:
When constant folding GEP of GEP, do not crash if an index of
the inner GEP is not a ConstantInt.

Added:
    llvm/trunk/test/Transforms/InstCombine/gepgep.ll
Modified:
    llvm/trunk/lib/Analysis/ConstantFolding.cpp

Modified: llvm/trunk/lib/Analysis/ConstantFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ConstantFolding.cpp?rev=98359&r1=98358&r2=98359&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ConstantFolding.cpp (original)
+++ llvm/trunk/lib/Analysis/ConstantFolding.cpp Fri Mar 12 11:55:20 2010
@@ -589,15 +589,28 @@
   APInt Offset = APInt(BitWidth,
                        TD->getIndexedOffset(Ptr->getType(),
                                             (Value**)Ops+1, NumOps-1));
+  Ptr = cast<Constant>(Ptr->stripPointerCasts());
 
   // If this is a GEP of a GEP, fold it all into a single GEP.
   while (GEPOperator *GEP = dyn_cast<GEPOperator>(Ptr)) {
     SmallVector<Value *, 4> NestedOps(GEP->op_begin()+1, GEP->op_end());
+
+    // Do not try the incorporate the sub-GEP if some index is not a number.
+    bool AllConstantInt = true;
+    for (unsigned i = 0, e = NestedOps.size(); i != e; ++i)
+      if (!isa<ConstantInt>(NestedOps[i])) {
+        AllConstantInt = false;
+        break;
+      }
+    if (!AllConstantInt)
+      break;
+
     Ptr = cast<Constant>(GEP->getOperand(0));
     Offset += APInt(BitWidth,
                     TD->getIndexedOffset(Ptr->getType(),
                                          (Value**)NestedOps.data(),
                                          NestedOps.size()));
+    Ptr = cast<Constant>(Ptr->stripPointerCasts());
   }
 
   // If the base value for this address is a literal integer value, fold the
@@ -611,7 +624,6 @@
   // we eliminate over-indexing of the notional static type array bounds.
   // This makes it easy to determine if the getelementptr is "inbounds".
   // Also, this helps GlobalOpt do SROA on GlobalVariables.
-  Ptr = cast<Constant>(Ptr->stripPointerCasts());
   const Type *Ty = Ptr->getType();
   SmallVector<Constant*, 32> NewIdxs;
   do {

Added: llvm/trunk/test/Transforms/InstCombine/gepgep.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/gepgep.ll?rev=98359&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/InstCombine/gepgep.ll (added)
+++ llvm/trunk/test/Transforms/InstCombine/gepgep.ll Fri Mar 12 11:55:20 2010
@@ -0,0 +1,13 @@
+; RUN: opt < %s -instcombine -disable-output
+
+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-n8:16:32:64"
+target triple = "x86_64-unknown-linux-gnu"
+
+ at buffer = external global [64 x float]
+
+declare void @use(i8*)
+
+define void @f() {
+  call void @use(i8* getelementptr (i8* getelementptr (i8* bitcast ([64 x float]* @buffer to i8*), i64 and (i64 sub (i64 0, i64 ptrtoint ([64 x float]* @buffer to i64)), i64 63)), i64 64))
+  ret void
+}