commit 9942b38103fcaba2a6350d97f2f504b2c3a28bc6
author Vladimir Marko <vmarko@google.com> Thu Jan 31 13:58:33 2019 +0000
committer Gerrit Code Review <noreply-gerritcodereview@google.com> Thu Jan 31 13:58:33 2019 +0000
tree 20b0276ec03980d1b8ca4cac2edd0dc4c21c5276
parent fcde77c303e19b7f4f734feb61fa58740d95d215
parent 53a41ac9305f3c435cbb975d773bbdb5490d8321

Merge "ART: Fix off-by-one error in BCE."

compiler/optimizing/bounds_check_elimination.cc

diff --git a/compiler/optimizing/bounds_check_elimination.cc b/compiler/optimizing/bounds_check_elimination.cc
index 54a1ae9..e35d502 100644
--- a/compiler/optimizing/bounds_check_elimination.cc
+++ b/compiler/optimizing/bounds_check_elimination.cc
@@ -845,8 +845,10 @@
           // make one more attempt to get a constant in the array range.
           ValueRange* existing_range = LookupValueRange(array_length, block);
           if (existing_range != nullptr &&
-              existing_range->IsConstantValueRange()) {
-            ValueRange constant_array_range(&allocator_, lower, existing_range->GetLower());
+              existing_range->IsConstantValueRange() &&
+              existing_range->GetLower().GetConstant() > 0) {
+            ValueBound constant_upper(nullptr, existing_range->GetLower().GetConstant() - 1);
+            ValueRange constant_array_range(&allocator_, lower, constant_upper);
             if (index_range->FitsIn(&constant_array_range)) {
               ReplaceInstruction(bounds_check, index);
               return;

test/622-checker-bce-regressions/src/Main.java

diff --git a/test/622-checker-bce-regressions/src/Main.java b/test/622-checker-bce-regressions/src/Main.java
index 6ba2644..595ade8 100644
--- a/test/622-checker-bce-regressions/src/Main.java
+++ b/test/622-checker-bce-regressions/src/Main.java
@@ -42,8 +42,22 @@
     return j;
   }
 
+  static public void $noinline$regressionTest123284765(String str) {
+    try {
+      int l = str.length();
+      if (l == 34) {
+        str.charAt(l);
+        fail();
+      }
+    } catch (StringIndexOutOfBoundsException expected) {
+      expectEquals(34, str.length());
+    }
+  }
+
   public static void main(String[] args) {
     expectEquals(8, doNotVisitAfterForwardBCE(array));
+    $noinline$regressionTest123284765("0123456789012345678901234567890123");
+    $noinline$regressionTest123284765("012345678901");
     System.out.println("passed");
   }
 
@@ -52,4 +66,8 @@
       throw new Error("Expected: " + expected + ", found: " + result);
     }
   }
+
+  private static void fail() {
+    throw new Error("FAIL");
+  }
 }