[Bug ipa/106077] New: Invalid IPA-SRA with non-call exceptions

[Bug ipa/106077] New: Invalid IPA-SRA with non-call exceptions

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106077

            Bug ID: 106077
           Summary: Invalid IPA-SRA with non-call exceptions
           Product: gcc
           Version: 13.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ipa
          Assignee: unassigned at gcc dot gnu.org
          Reporter: hubicka at gcc dot gnu.org
                CC: marxin at gcc dot gnu.org
  Target Milestone: ---

Compiled with -O2 -fno-ipa-cp we make t() to trap instead of calling
non-call-exception from wrap

short e,f;
static __attribute__ ((noinline))
int a(int *b)
{
        return *b;
}
static __attribute__ ((noinline))
__attribute__ ((optimize("non-call-exceptions")))
int wrap(int *b,int e, int f)
{
        e/=f;
        return a(b)+e;
}

int
t()
{
        return wrap(0,1,0);
}

[Bug ipa/106077] Invalid IPA-SRA with non-call exceptions

[hubicka at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106077

--- Comment #1 from Jan Hubicka <hubicka at gcc dot gnu.org> ---
Also note that the dominance check is written the wrong way, so it only passes
for first BB in the function

diff --git a/gcc/ipa-sra.cc b/gcc/ipa-sra.cc
index 96b020fb2dd..6b2df2f3ff0 100644
--- a/gcc/ipa-sra.cc
+++ b/gcc/ipa-sra.cc
@@ -2403,8 +2403,8 @@ process_scan_results (cgraph_node *node, struct function
*fun,
                pdoms_calculated = true;
              }
            if (dominated_by_p (CDI_POST_DOMINATORS,
-                               gimple_bb (call_stmt),
-                               single_succ (ENTRY_BLOCK_PTR_FOR_FN (fun))))
+                               single_succ (ENTRY_BLOCK_PTR_FOR_FN (fun))
+                               gimple_bb (call_stmt)))
              csum->m_arg_flow[argidx].safe_to_import_accesses = true;
          }

[Bug ipa/106077] Invalid IPA-SRA with non-call exceptions

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106077

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

https://gcc.gnu.org/g:b1f30bf42d8d47228e52de998f3172b2f5dd7265

commit r13-5215-gb1f30bf42d8d47228e52de998f3172b2f5dd7265
Author: Jan Hubicka <jh@suse.cz>
Date:   Mon Jan 16 18:14:45 2023 +0100

    Fix wrong code issues with ipa-sra

    Fix wrong code issues in ipa-sra where we are trying to prove that on every
    execution of a given function a call to other function will happen.  The
code
    uses post dominators and makes a wrong query (which passes only for first
BB in
    function). Hoever post-dominators are only valid if fake edges for every
    possible reason for fuction execution to terminate are added.

    Fixing this using postdominators is somewhat costy since one needs to walk
    whole body and add a lot of fake edges. I ended up implementing a special
    purpose function for this which is also useful in ipa-modref and other
places
    that does similar analysis.  One does not need to modify CFG to use it and
    moreover for complex functions it usually stops on first unanalyzed
function
    call and ends up being relatively cheap.

    Bootstrapped/regtested x86_64-linux, plan to commit it shortly.

    gcc/ChangeLog:

    2023-01-16  Jan Hubicka  <hubicka@ucw.cz>

            PR ipa/106077
            * ipa-modref.cc (modref_access_analysis::analyze): Use
            find_always_executed_bbs.
            * ipa-sra.cc (process_scan_results): Likewise.
            * ipa-utils.cc (stmt_may_terminate_function_p): New function.
            (find_always_executed_bbs): New function.
            * ipa-utils.h (stmt_may_terminate_function_p): Declare.
            (find_always_executed_bbs): Declare.

    gcc/testsuite/ChangeLog:

    2023-01-16  Jan Hubicka  <hubicka@ucw.cz>

            * g++.dg/tree-ssa/pr106077.C: New test.