tree-ssa-loop-niter.h (number_of_iterations_exit_assumptions): New Parameter.
* tree-ssa-loop-niter.h (number_of_iterations_exit_assumptions): New Parameter. * tree-ssa-loop-niter.c (number_of_iterations_exit_assumptions): New Parameter. (number_of_iterations_exit): Warn missed loop optimization for possible infinite loops. gcc/testsuite * gcc.dg/tree-ssa/pr19210-1.c: Refine test strings. * gcc.dg/tree-ssa/pr19210-2.c: Delete. From-SVN: r238641
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@ -1,3 +1,12 @@
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2016-07-22 Bin Cheng <bin.cheng@arm.com>
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* tree-ssa-loop-niter.h (number_of_iterations_exit_assumptions): New
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Parameter.
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* tree-ssa-loop-niter.c (number_of_iterations_exit_assumptions): New
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Parameter.
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(number_of_iterations_exit): Warn missed loop optimization for
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possible infinite loops.
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2016-07-22 Segher Boessenkool <segher@kernel.crashing.org>
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* config/rs6000/rs6000.c (rs6000_file_start): Fix condition for
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@ -1,3 +1,8 @@
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2016-07-22 Bin Cheng <bin.cheng@arm.com>
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* gcc.dg/tree-ssa/pr19210-1.c: Refine test strings.
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* gcc.dg/tree-ssa/pr19210-2.c: Delete.
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2016-07-22 Thomas Koenig <tkoenig@gcc.gnu.org>
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PR fortran/71795
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@ -6,10 +6,10 @@ void
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f (unsigned n)
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{
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unsigned k;
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for(k = 0;k <= n;k++) /* { dg-warning "cannot optimize.*infinite loops" } */
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for(k = 0;k <= n;k++) /* { dg-warning "missed loop optimization.*overflow" } */
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g();
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for(k = 0;k <= n;k += 4) /* { dg-warning "cannot optimize.*overflow" } */
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for(k = 0;k <= n;k += 4) /* { dg-warning "missed loop optimization.*overflow" } */
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g();
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/* We used to get warning for this loop. However, since then # of iterations
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@ -21,9 +21,9 @@ f (unsigned n)
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g();
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/* So we need the following loop, instead. */
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for(k = 4;k <= n;k += 5) /* { dg-warning "cannot optimize.*overflow" } */
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for(k = 4;k <= n;k += 5) /* { dg-warning "missed loop optimization.*overflow" } */
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g();
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for(k = 15;k >= n;k--) /* { dg-warning "cannot optimize.*infinite" } */
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for(k = 15;k >= n;k--) /* { dg-warning "missed loop optimization.*overflow" } */
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g();
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}
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@ -1,29 +0,0 @@
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/* { dg-do compile } */
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/* { dg-options "-O2 -funsafe-loop-optimizations -Wunsafe-loop-optimizations" } */
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extern void g(void);
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void
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f (unsigned n)
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{
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unsigned k;
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for(k = 0;k <= n;k++) /* { dg-warning "assuming.*not infinite" } */
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g();
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for(k = 5;k <= n;k += 4) /* { dg-warning "assuming.*not overflow" } */
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g();
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/* We used to get warning for this loop. However, since then # of iterations
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analysis improved, and we can now prove that this loop does not verflow.
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This is because the only case when it would overflow is if n = ~0 (since
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~0 is divisible by 5), and this cannot be the case, since when we got
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here, the previous loop exited, thus there exists k > n. */
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for(k = 5;k <= n;k += 5)
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g();
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for(k = 4;k <= n;k += 5) /* { dg-warning "assuming.*not overflow" } */
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g();
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for(k = 15;k >= n;k--) /* { dg-warning "assuming.*not infinite" } */
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g();
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}
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@ -2132,12 +2132,13 @@ loop_only_exit_p (const struct loop *loop, const_edge exit)
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in comments at struct tree_niter_desc declaration), false otherwise.
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When EVERY_ITERATION is true, only tests that are known to be executed
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every iteration are considered (i.e. only test that alone bounds the loop).
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*/
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If AT_STMT is not NULL, this function stores LOOP's condition statement in
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it when returning true. */
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bool
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number_of_iterations_exit_assumptions (struct loop *loop, edge exit,
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struct tree_niter_desc *niter,
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bool every_iteration)
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gcond **at_stmt, bool every_iteration)
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{
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gimple *last;
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gcond *stmt;
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if (TREE_CODE (niter->niter) == INTEGER_CST)
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niter->max = wi::to_widest (niter->niter);
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if (at_stmt)
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*at_stmt = stmt;
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return (!integer_zerop (niter->assumptions));
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}
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@ -2263,13 +2267,26 @@ number_of_iterations_exit_assumptions (struct loop *loop, edge exit,
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bool
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number_of_iterations_exit (struct loop *loop, edge exit,
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struct tree_niter_desc *niter,
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bool, bool every_iteration)
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bool warn, bool every_iteration)
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{
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gcond *stmt;
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if (!number_of_iterations_exit_assumptions (loop, exit, niter,
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every_iteration))
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&stmt, every_iteration))
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return false;
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return (integer_nonzerop (niter->assumptions));
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if (integer_nonzerop (niter->assumptions))
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return true;
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if (warn)
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{
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const char *wording;
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wording = N_("missed loop optimization, the loop counter may overflow");
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warning_at (gimple_location_safe (stmt),
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OPT_Wunsafe_loop_optimizations, "%s", gettext (wording));
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}
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return false;
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}
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/* Try to determine the number of iterations of LOOP. If we succeed,
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@ -29,7 +29,7 @@ extern bool number_of_iterations_exit (struct loop *, edge,
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bool every_iteration = true);
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extern bool number_of_iterations_exit_assumptions (struct loop *, edge,
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struct tree_niter_desc *,
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bool = true);
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gcond **, bool = true);
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extern tree find_loop_niter (struct loop *, edge *);
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extern bool finite_loop_p (struct loop *);
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extern tree loop_niter_by_eval (struct loop *, edge);
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