[llvm-bugs] [Bug 42765] New: Avoid spilling the address of the saved stack guard with -fstack-protector

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=42765

            Bug ID: 42765
           Summary: Avoid spilling the address of the saved stack guard
                    with -fstack-protector
           Product: libraries
           Version: trunk
          Hardware: PC
                OS: All
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: Common Code Generator Code
          Assignee: unassignedbugs at nondot.org
          Reporter: francisvm at yahoo.com
                CC: llvm-bugs at lists.llvm.org

In https://reviews.llvm.org/D64759, we avoid using a different register to
address the slot of the stack guard to be loaded before we compare it with the
original guard.

There are cases where this could still be spilled, potentially by the reg
scavenger.

A few things we could do to make this better:

* Eli Friedman suggested to make the reg scavenger aware of particularly
sensitive registers and force it to choose other registers to spill.
* Sander de Smalen suggested to always enable FP when using stack guards.

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20190725/db8a3ba8/attachment.html>