[llvm] r287604 - Analysis: gep inbounds (gep inbounds (...)) is inbounds.

[Peter Collingbourne via llvm-commits]

Author: pcc
Date: Mon Nov 21 19:03:40 2016
New Revision: 287604

URL: http://llvm.org/viewvc/llvm-project?rev=287604&view=rev
Log:
Analysis: gep inbounds (gep inbounds (...)) is inbounds.

Differential Revision: https://reviews.llvm.org/D26441

Modified:
    llvm/trunk/lib/Analysis/ConstantFolding.cpp
    llvm/trunk/test/Other/constant-fold-gep.ll

Modified: llvm/trunk/lib/Analysis/ConstantFolding.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Analysis/ConstantFolding.cpp?rev=287604&r1=287603&r2=287604&view=diff
==============================================================================
--- llvm/trunk/lib/Analysis/ConstantFolding.cpp (original)
+++ llvm/trunk/lib/Analysis/ConstantFolding.cpp Mon Nov 21 19:03:40 2016
@@ -773,6 +773,7 @@ Constant *SymbolicallyEvaluateGEP(const
                                   const DataLayout &DL,
                                   const TargetLibraryInfo *TLI) {
   const GEPOperator *InnermostGEP = GEP;
+  bool InBounds = GEP->isInBounds();
 
   Type *SrcElemTy = GEP->getSourceElementType();
   Type *ResElemTy = GEP->getResultElementType();
@@ -825,6 +826,7 @@ Constant *SymbolicallyEvaluateGEP(const
   // If this is a GEP of a GEP, fold it all into a single GEP.
   while (auto *GEP = dyn_cast<GEPOperator>(Ptr)) {
     InnermostGEP = GEP;
+    InBounds &= GEP->isInBounds();
 
     SmallVector<Value *, 4> NestedOps(GEP->op_begin() + 1, GEP->op_end());
 
@@ -946,8 +948,8 @@ Constant *SymbolicallyEvaluateGEP(const
     }
 
   // Create a GEP.
-  Constant *C = ConstantExpr::getGetElementPtr(
-      SrcElemTy, Ptr, NewIdxs, /*InBounds=*/false, InRangeIndex);
+  Constant *C = ConstantExpr::getGetElementPtr(SrcElemTy, Ptr, NewIdxs,
+                                               InBounds, InRangeIndex);
   assert(C->getType()->getPointerElementType() == Ty &&
          "Computed GetElementPtr has unexpected type!");
 

Modified: llvm/trunk/test/Other/constant-fold-gep.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Other/constant-fold-gep.ll?rev=287604&r1=287603&r2=287604&view=diff
==============================================================================
--- llvm/trunk/test/Other/constant-fold-gep.ll (original)
+++ llvm/trunk/test/Other/constant-fold-gep.ll Mon Nov 21 19:03:40 2016
@@ -106,9 +106,9 @@
 
 ; PLAIN: @Y = global [3 x { i32, i32 }]* getelementptr inbounds ([3 x { i32, i32 }], [3 x { i32, i32 }]* @ext, i64 2)
 ; PLAIN: @Z = global i32* getelementptr inbounds (i32, i32* getelementptr inbounds ([3 x { i32, i32 }], [3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 0), i64 1)
-; OPT: @Y = local_unnamed_addr global [3 x { i32, i32 }]* getelementptr ([3 x { i32, i32 }], [3 x { i32, i32 }]* @ext, i64 2)
+; OPT: @Y = local_unnamed_addr global [3 x { i32, i32 }]* getelementptr inbounds ([3 x { i32, i32 }], [3 x { i32, i32 }]* @ext, i64 2)
 ; OPT: @Z = local_unnamed_addr global i32* getelementptr inbounds ([3 x { i32, i32 }], [3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 1)
-; TO: @Y = local_unnamed_addr global [3 x { i32, i32 }]* getelementptr ([3 x { i32, i32 }], [3 x { i32, i32 }]* @ext, i64 2)
+; TO: @Y = local_unnamed_addr global [3 x { i32, i32 }]* getelementptr inbounds ([3 x { i32, i32 }], [3 x { i32, i32 }]* @ext, i64 2)
 ; TO: @Z = local_unnamed_addr global i32* getelementptr inbounds ([3 x { i32, i32 }], [3 x { i32, i32 }]* @ext, i64 0, i64 1, i32 1)
 
 @ext = external global [3 x { i32, i32 }]