BasicAA: Recognize inttoptr as isEscapeSource

Pointers escape when converted to integers, so a pointer produced by
converting an integer to a pointer must not be a local non-escaping
object.

Reviewed By: nikic, nlopes, aqjune

Differential Revision: https://reviews.llvm.org/D101541

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/BasicAliasAnalysis.cpp b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
index 963fb1a..dec7fcb 100644
--- a/llvm/lib/Analysis/BasicAliasAnalysis.cpp
+++ b/llvm/lib/Analysis/BasicAliasAnalysis.cpp
@@ -129,6 +129,14 @@ static bool isEscapeSource(const Value *V) {
   if (isa<LoadInst>(V))
     return true;
 
+  // The inttoptr case works because isNonEscapingLocalObject considers all
+  // means of converting or equating a pointer to an int (ptrtoint, ptr store
+  // which could be followed by an integer load, ptr<->int compare) as
+  // escaping, and objects located at well-known addresses via platform-specific
+  // means cannot be considered non-escaping local objects.
+  if (isa<IntToPtrInst>(V))
+    return true;
+
   return false;
 }