[Bug tree-optimization/63748] [4.9 Regression] wrong may be used uninitialized warning (abnormal edges)

["manu at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63748

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |24639
         Depends on|24639                       |

--- Comment #10 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
Fix blocks/depends list
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Subject: [Bug middle-end/60741] [-Wmaybe-uninitialized] false negative and confusing warning message
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=60741

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

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--- Comment #3 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
Fix blocks/depends list.
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Subject: [Bug fortran/56670] Allocatable-length character var causes bogus warning with -Wall
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56670

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |manu at gcc dot gnu.org
             Blocks|                            |24639
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--- Comment #2 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
Fix blocks/depends list.
>From gcc-bugs-return-478208-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Mon Feb 23 17:58:06 2015
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Subject: [Bug tree-optimization/65178] incorrect -Wmaybe-uninitialized when using nested loops
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65178

Manuel López-Ibáñez <manu at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |diagnostic
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-02-23
                 CC|                            |manu at gcc dot gnu.org
             Blocks|                            |24639
     Ever confirmed|0                           |1

--- Comment #1 from Manuel López-Ibáñez <manu at gcc dot gnu.org> ---
A minimized testcase:

void *bar(int);
char *
foo (void)
{ 
  char *c = "bla";
  char *buf;
  for (int a = 1;; a = 0)
    { 
      for (char *s = c; *s; ++s)
        { 
        }
      if (!a) break;
      buf = (char *) bar (1);
    }
  return buf;
}

It fails in GCC 5.0 with -O1, -O2 and -O3. I think we have several reports
about this: GCC simply does not understand that the loop body is executed at
least once, thus there should be no (default) entry edge for the PHI node of
buf.

I think it is a missed optimization also: If buf were initialized, the initial
value could be dropped.
>From gcc-bugs-return-478209-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Mon Feb 23 18:05:50 2015
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Subject: [Bug fortran/61831] [4.9/ 5 Regression] runtime error: pointer being freed was not allocated
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--- Comment #42 from Mikael Morin <mikael at gcc dot gnu.org> ---
(In reply to Mikael Morin from comment #41)
> My work patch is:

updated work patch below.
The testcase passes with it, at the price of leaking memory

Index: trans-expr.c
===================================================================
--- trans-expr.c    (révision 220717)
+++ trans-expr.c    (copie de travail)
@@ -4949,7 +4949,8 @@ gfc_conv_procedure_call (gfc_se * se, gfc_symbol *
       if (e && (e->ts.type == BT_DERIVED || e->ts.type == BT_CLASS)
         && e->ts.u.derived->attr.alloc_comp
         && !(e->symtree && e->symtree->n.sym->attr.pointer)
-        && (e->expr_type != EXPR_VARIABLE && !e->rank))
+        && (e->expr_type != EXPR_VARIABLE
+        && e->expr_type != EXPR_STRUCTURE && !e->rank))
         {
       int parm_rank;
       tmp = build_fold_indirect_ref_loc (input_location,
@@ -7131,7 +7132,8 @@ gfc_conv_expr_reference (gfc_se * se, gfc_expr * e
   if (expr->ts.type == BT_DERIVED && expr->rank
       && !gfc_is_finalizable (expr->ts.u.derived, NULL)
       && expr->ts.u.derived->attr.alloc_comp
-      && expr->expr_type != EXPR_VARIABLE)
+      && expr->expr_type != EXPR_VARIABLE
+      && expr->expr_type != EXPR_ARRAY)
     {
       tree tmp;
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Subject: [Bug bootstrap/65150] [5 Regression] r220875 causes bootstrap failure on x86_64 darwin
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https://gcc.gnu.org/bugzilla/show_bug.cgi?ide150

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Iain Sandoe from comment #7)
> here we fall through to the case were we make a thunk - IFF we were not able
> to rmove the alias.  However, potentially, we already moved all the callers
> from the alias to the original.
>
> (a) is that safe?

Why not?

> (b) we might as well avoid the work by testing whether the alias will be
> removable before we set redirect_callers?

Redirecting the callers is beneficial even when we create trunk.
For the redirected callers, they will jump directly to the right function,
while
without redirection you call a thunk, which in the better case just jumps to
the right function (ie. sibcall), in the worse case calls it and then returns.
So you save a few instructions on each redirected call.
When alias is created instead of redirection (in that case we don't redirect
callers right now), the only advantage of redirection would be tail recursion.