Return Undef from isBytewiseValue for empty arrays or structs

Reviewers: pcc, eugenis Subscribers: hiraditya, llvm-commits Tags: #llvm Differential Revision: https://reviews.llvm.org/D64052 llvm-svn: 365864
llvm · Jul 12, 2019 · 52096ee · 52096ee
1 parent 8bd441a
commit 52096ee
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Showing 2 changed files with 8 additions and 4 deletions.
diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
@@ -3178,6 +3178,10 @@ Value *llvm::isBytewiseValue(Value *V, const DataLayout &DL) {
   if (isa<UndefValue>(V))
     return UndefInt8;
 
+  const uint64_t Size = DL.getTypeStoreSize(V->getType());
+  if (!Size)
+    return UndefInt8;
+
   Constant *C = dyn_cast<Constant>(V);
   if (!C) {
     // Conceptually, we could handle things like:

diff --git a/llvm/unittests/Analysis/ValueTrackingTest.cpp b/llvm/unittests/Analysis/ValueTrackingTest.cpp
@@ -810,15 +810,15 @@ const std::pair<const char *, const char *> IsBytewiseValueTests[] = {
         "i16* inttoptr (i96 -1 to i16*)",
     },
     {
-        "i8 0",
+        "i8 undef",
         "[0 x i8] zeroinitializer",
     },
     {
         "i8 undef",
         "[0 x i8] undef",
     },
     {
-        "i8 0",
+        "i8 undef",
         "[5 x [0 x i8]] zeroinitializer",
     },
     {
@@ -900,15 +900,15 @@ const std::pair<const char *, const char *> IsBytewiseValueTests[] = {
         "[2 x i16] [i16 -21836, i16 -21846]]",
     },
     {
-        "i8 0",
+        "i8 undef",
         "{ } zeroinitializer",
     },
     {
         "i8 undef",
         "{ } undef",
     },
     {
-        "i8 0",
+        "i8 undef",
         "{ {}, {} } zeroinitializer",
     },
     {