[Bug tree-optimization/101293] New: LIM ref canonicalization incomplete

[Bug tree-optimization/101293] New: LIM ref canonicalization incomplete

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101293

            Bug ID: 101293
           Summary: LIM ref canonicalization incomplete
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

We fail to apply store-motion to

struct X { int i; int j; };

void foo(struct X *x, int n)
{
  for (int i = 0; i < n; ++i)
    {
      int *p = &x->j;
      int tem = *p;
      x->j += tem * i;
    }
}

because we end up with two distinct memory references:

Memory reference 1: MEM[(int *)x_7(D) + 4B]
Memory reference 2: x_7(D)->j

[Bug tree-optimization/101293] LIM ref canonicalization incomplete

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101293

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
   Last reconfirmed|                            |2021-07-02
     Ever confirmed|0                           |1
           Keywords|                            |missed-optimization
             Status|UNCONFIRMED                 |ASSIGNED
             Blocks|                            |99728

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Mine.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99728
[Bug 99728] code pessimization when using wrapper classes around SIMD types

[Bug tree-optimization/101293] LIM ref canonicalization incomplete

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101293

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Biener <rguenth@gcc.gnu.org>:

https://gcc.gnu.org/g:4546f423ecff96f223adfbec4963d2ff17f27c7b

commit r12-1977-g4546f423ecff96f223adfbec4963d2ff17f27c7b
Author: Richard Biener <rguenther@suse.de>
Date:   Fri Jul 2 12:57:06 2021 +0200

    tree-optimization/101293 - further enhance LIMs ref canonicalization

    This makes sure to handle MEM[p + 4] and MEM[p].j with j at offset 4
    as the same ref in store motion.  For hashing we need to be
    more restrictive in what we handle since there's no poly-int
    handlers for inchash.  For comparison we can compare poly_offsets directly.

    2021-07-02  Richard Biener  <rguenther@suse.de>

            PR tree-optimization/101293
            * tree-ssa-loop-im.c (mem_ref_hasher::equal): Compare MEM_REF bases
            with combined offsets.
            (gather_mem_refs_stmt): Hash MEM_REFs as if their offset were
            combined with the rest of the offset.

            * gcc.dg/tree-ssa/ssa-lim-15.c: New testcase.

[Bug tree-optimization/101293] LIM ref canonicalization incomplete

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101293

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed.