RFR: 8311010: C1 array access causes SIGSEGV due to lack of range check

[Yi Yang]

int[] a = { 11 } ;
        for (int i = -1; i <= 0; i++) {
            for (int j = -3; j <= 2147483646 * i - 3; j++) {
                b += a[j + 3];
            }
        }

C1 eliminates range check before accessing array, because he did the following deduction:

   lower - const <= x <= upper - const
   lower <= x + const <= upper

 This is wrong, because (lower - const + const) and  (upper -  const + const) may overflow/underflow, e.g.

    -3 <= x     <= min_jint - 3
    0  <= x + 3 <= min_jint    (wrong)

The proposed change is to assume the worst case whenever upper or lower is found, which may be somewhat conservative.

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Commit messages:
 - 8311010 C1 array access causes SIGSEGV due to lack of range check

Changes: https://git.openjdk.org/jdk/pull/14689/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=14689&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8311010
  Stats: 71 lines in 2 files changed: 69 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/14689.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/14689/head:pull/14689

PR: https://git.openjdk.org/jdk/pull/14689