[LLVMbugs] [Bug 12420] New: Missed instcombine with pointer differences.

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=12420

             Bug #: 12420
           Summary: Missed instcombine with pointer differences.
           Product: libraries
           Version: trunk
          Platform: PC
        OS/Version: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Scalar Optimizations
        AssignedTo: unassignedbugs at nondot.org
        ReportedBy: benny.kra at gmail.com
                CC: llvmbugs at cs.uiuc.edu
    Classification: Unclassified


>From GCC PR 21082 (mgrid):

---8<---

typedef __SIZE_TYPE__ size_t;
size_t a[100];
size_t f(size_t b, size_t c)
{
  return &a[b] - &a[c] != b - c;
}

--->8---

Should fold to "false". Looks like something isn't preserving overflow flags.

-- 
Configure bugmail: http://llvm.org/bugs/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are on the CC list for the bug.