diff mbox series

tree-optimization/104528 - free niter estimates after DSE

Message ID 20220214133100.7431113B2B@imap2.suse-dmz.suse.de
State New
Headers show
Series tree-optimization/104528 - free niter estimates after DSE | expand

Commit Message

Richard Biener Feb. 14, 2022, 1:30 p.m. UTC 
When DSE removes a trivially dead def we have to reset niter information
on loops since that might refer to it.  The patch also adds verification
to make sure this does not happen.

Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.

2022-02-14  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/104528
	* tree-ssa.h (find_released_ssa_name): Declare.
	* tree-ssa.cc (find_released_ssa_name): Export.
	* cfgloop.cc (verify_loop_structure): Look for released
	SSA names in loops nb_iterations.
	* tree-ssa-dse.cc (pass_dse::execute): Release number of iteration
	estimates.

	* gfortran.dg/pr104528.f: New testcase.
---
 gcc/cfgloop.cc                       | 13 ++++++++
 gcc/testsuite/gfortran.dg/pr104528.f | 44 ++++++++++++++++++++++++++++
 gcc/tree-ssa-dse.cc                  |  8 +++++
 gcc/tree-ssa.cc                      |  2 +-
 gcc/tree-ssa.h                       |  1 +
 5 files changed, 67 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gfortran.dg/pr104528.f
diff mbox series

Patch

diff --git a/gcc/cfgloop.cc b/gcc/cfgloop.cc
index 78fd6d5db1b..5ffcc77d93f 100644
--- a/gcc/cfgloop.cc
+++ b/gcc/cfgloop.cc
@@ -31,6 +31,8 @@  along with GCC; see the file COPYING3.  If not see
 #include "cfgloop.h"
 #include "gimple-iterator.h"
 #include "dumpfile.h"
+#include "tree-ssa.h"
+#include "tree-pretty-print.h"
 
 static void flow_loops_cfg_dump (FILE *);
 
@@ -1561,6 +1563,17 @@  verify_loop_structure (void)
 		err = 1;
 	      }
 	}
+
+      /* Check cached number of iterations for released SSA names.  */
+      tree ref;
+      if (loop->nb_iterations
+	  && (ref = walk_tree (&loop->nb_iterations,
+			       find_released_ssa_name, NULL, NULL)))
+	{
+	  error ("loop %d%'s number of iterations %qE references the"
+		 " released SSA name %qE", i, loop->nb_iterations, ref);
+	  err = 1;
+	}
     }
 
   /* Check irreducible loops.  */
diff --git a/gcc/testsuite/gfortran.dg/pr104528.f b/gcc/testsuite/gfortran.dg/pr104528.f
new file mode 100644
index 00000000000..5b43feba97b
--- /dev/null
+++ b/gcc/testsuite/gfortran.dg/pr104528.f
@@ -0,0 +1,44 @@ 
+! { dg-do compile }
+! { dg-options "-O2 -fpeel-loops -ftree-loop-vectorize -fno-tree-scev-cprop --param iv-max-considered-uses=2" }
+      REAL               FUNCTION FOO(M, N, A, W)
+
+      INTEGER            M, N
+
+      REAL               W(*)
+      COMPLEX            A(*)
+
+      INTEGER            II, JI, JJ, KK, LL, MP
+
+      EXTERNAL           BAR
+
+      INTEGER            QUX
+      EXTERNAL           QUX
+
+      CALL BAR(II)
+
+      IF (M .EQ. 0) THEN
+         IF (N .EQ. 0) THEN
+            DO 140 KK = II, II + MP
+               W(KK) = 0
+ 140        CONTINUE
+         ELSE
+            KK = II + MP
+         END IF
+
+         DO 130 JI = KK, KK + MP
+            DO 120 LL = JJ, JJ + MP
+               DO 110 KK = II, II + MP
+                  W(KK) = (A(KK))
+ 110           CONTINUE
+ 120        CONTINUE
+ 130     CONTINUE
+
+         IF (W(KK) .EQ. 0) THEN
+            FOO = W(QUX(MP, W, 1))
+         END IF
+
+      END IF
+
+      RETURN
+
+      END
diff --git a/gcc/tree-ssa-dse.cc b/gcc/tree-ssa-dse.cc
index 47997df2125..2b22a61ad97 100644
--- a/gcc/tree-ssa-dse.cc
+++ b/gcc/tree-ssa-dse.cc
@@ -44,6 +44,7 @@  along with GCC; see the file COPYING3.  If not see
 #include "ipa-modref-tree.h"
 #include "ipa-modref.h"
 #include "target.h"
+#include "tree-ssa-loop-niter.h"
 
 /* This file implements dead store elimination.
 
@@ -1418,6 +1419,8 @@  unsigned int
 pass_dse::execute (function *fun)
 {
   unsigned todo = 0;
+  bool released_def = false;
+
   need_eh_cleanup = BITMAP_ALLOC (NULL);
   need_ab_cleanup = BITMAP_ALLOC (NULL);
   auto_sbitmap live_bytes (param_dse_max_object_size);
@@ -1460,6 +1463,7 @@  pass_dse::execute (function *fun)
 		  if (gsi_remove (&gsi, true) && need_eh_cleanup)
 		    bitmap_set_bit (need_eh_cleanup, bb->index);
 		  release_defs (stmt);
+		  released_def = true;
 		}
 	    }
 	  if (gsi_end_p (gsi))
@@ -1481,6 +1485,7 @@  pass_dse::execute (function *fun)
 		}
 	      remove_phi_node (&si, true);
 	      removed_phi = true;
+	      released_def = true;
 	    }
 	  else
 	    gsi_next (&si);
@@ -1506,6 +1511,9 @@  pass_dse::execute (function *fun)
   BITMAP_FREE (need_eh_cleanup);
   BITMAP_FREE (need_ab_cleanup);
 
+  if (released_def)
+    free_numbers_of_iterations_estimates (fun);
+
   return todo;
 }
 
diff --git a/gcc/tree-ssa.cc b/gcc/tree-ssa.cc
index 8fe0682981d..430875ae37a 100644
--- a/gcc/tree-ssa.cc
+++ b/gcc/tree-ssa.cc
@@ -272,7 +272,7 @@  target_for_debug_bind (tree var)
 /* Called via walk_tree, look for SSA_NAMEs that have already been
    released.  */
 
-static tree
+tree
 find_released_ssa_name (tree *tp, int *walk_subtrees, void *data_)
 {
   struct walk_stmt_info *wi = (struct walk_stmt_info *) data_;
diff --git a/gcc/tree-ssa.h b/gcc/tree-ssa.h
index 36ddea276b5..008535454a8 100644
--- a/gcc/tree-ssa.h
+++ b/gcc/tree-ssa.h
@@ -49,6 +49,7 @@  extern void init_tree_ssa (function *, int size = 0);
 extern void delete_tree_ssa (function *);
 extern bool tree_ssa_useless_type_conversion (tree);
 extern tree tree_ssa_strip_useless_type_conversions (tree);
+extern tree find_released_ssa_name (tree *, int *, void *);
 
 
 extern bool ssa_defined_default_def_p (tree t);