[PATCH] Move substitute_and_fold over to use simple_dce_from_worklist

[Andrew Pinski <apinski@marvell.com>]

While looking into a different issue, I noticed that it
would take until the second forwprop pass to do some
forward proping and it was because the ssa name was
used more than once but the second statement was
"dead" and we don't remove that until much later.

So this uses simple_dce_from_worklist instead of manually
removing of the known unused statements instead.
Propagate engine does not do a cleanupcfg afterwards either but manually
cleans up possible EH edges so simple_dce_from_worklist
needs to communicate that back to the propagate engine.

Some testcases needed to be updated/changed even because of better optimization.
gcc.dg/pr81192.c even had to be changed to be using the gimple FE so it would
be less fragile in the future too.
gcc.dg/tree-ssa/pr98737-1.c was failing because __atomic_fetch_ was being matched
but in those cases, the result was not being used so both __atomic_fetch_ and
__atomic_x_and_fetch_ are valid choices and would not make a code generation difference.
evrp7.c, evrp8.c, vrp35.c, vrp36.c: just needed a slightly change as the removal message
is different slightly.
kernels-alias-8.c: ccp1 is able to remove an unused load which causes ealias to have
one less load to analysis so update the expected scan #.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

gcc/ChangeLog:

	PR tree-optimization/109691
	* tree-ssa-dce.cc (simple_dce_from_worklist): Add need_eh_cleanup
	argument.
	If the removed statement can throw, have need_eh_cleanup
	include the bb of that statement.
	* tree-ssa-dce.h (simple_dce_from_worklist): Update declaration.
	* tree-ssa-propagate.cc (struct prop_stats_d): Remove
	num_dce.
	(substitute_and_fold_dom_walker::substitute_and_fold_dom_walker):
	Initialize dceworklist instead of stmts_to_remove.
	(substitute_and_fold_dom_walker::~substitute_and_fold_dom_walker):
	Destore dceworklist instead of stmts_to_remove.
	(substitute_and_fold_dom_walker::before_dom_children):
	Set dceworklist instead of adding to stmts_to_remove.
	(substitute_and_fold_engine::substitute_and_fold):
	Call simple_dce_from_worklist instead of poping
	from the list.
	Don't update the stat on removal statements.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/evrp7.c: Update for output change.
	* gcc.dg/tree-ssa/evrp8.c: Likewise.
	* gcc.dg/tree-ssa/vrp35.c: Likewise.
	* gcc.dg/tree-ssa/vrp36.c: Likewise.
	* gcc.dg/tree-ssa/pr98737-1.c: Update scan-tree-dump-not
	to check for assignment too instead of just a call.
	* c-c++-common/goacc/kernels-alias-8.c: Update test
	for removal of load.
	* gcc.dg/pr81192.c: Rewrite testcase in gimple based test.
---
 .../c-c++-common/goacc/kernels-alias-8.c      |  6 +-
 gcc/testsuite/gcc.dg/pr81192.c                | 64 ++++++++++++++++---
 gcc/testsuite/gcc.dg/tree-ssa/evrp7.c         |  2 +-
 gcc/testsuite/gcc.dg/tree-ssa/evrp8.c         |  2 +-
 gcc/testsuite/gcc.dg/tree-ssa/pr98737-1.c     |  7 +-
 gcc/testsuite/gcc.dg/tree-ssa/vrp35.c         |  2 +-
 gcc/testsuite/gcc.dg/tree-ssa/vrp36.c         |  2 +-
 gcc/tree-ssa-dce.cc                           |  7 +-
 gcc/tree-ssa-dce.h                            |  2 +-
 gcc/tree-ssa-propagate.cc                     | 39 ++---------
 10 files changed, 82 insertions(+), 51 deletions(-)

diff --git a/gcc/testsuite/c-c++-common/goacc/kernels-alias-8.c b/gcc/testsuite/c-c++-common/goacc/kernels-alias-8.c
index 69200ccf192..c3922e33241 100644
--- a/gcc/testsuite/c-c++-common/goacc/kernels-alias-8.c
+++ b/gcc/testsuite/c-c++-common/goacc/kernels-alias-8.c
@@ -16,7 +16,9 @@ foo (int *a, size_t n)
   }
 }
 
-/* Only the omp_data_i related loads should be annotated with cliques.  */
-/* { dg-final { scan-tree-dump-times "clique 1 base 1" 2 "ealias" } } */
+/* Only the omp_data_i related loads should be annotated with cliques.
+   Note ccp can remove one of the omp_data_i loads which is why there
+   is there only one clique base still there.  */
+/* { dg-final { scan-tree-dump-times "clique 1 base 1" 1 "ealias" } } */
 /* { dg-final { scan-tree-dump-times "(?n)clique 1 base 0" 2 "ealias" } } */
 
diff --git a/gcc/testsuite/gcc.dg/pr81192.c b/gcc/testsuite/gcc.dg/pr81192.c
index 6cab6056558..f6d201ee71a 100644
--- a/gcc/testsuite/gcc.dg/pr81192.c
+++ b/gcc/testsuite/gcc.dg/pr81192.c
@@ -1,5 +1,58 @@
-/* { dg-options "-Os -fdump-tree-pre-details -fdisable-tree-evrp -fno-tree-dse" } */
+/* { dg-options "-Os -fgimple -fdump-tree-pre-details -fdisable-tree-evrp -fno-tree-dse" } */
 
+#if __SIZEOF_INT__ == 2
+#define unsigned __UINT32_TYPE__
+#define int __INT32_TYPE__
+#endif
+
+unsigned a;
+int b, c;
+
+void __GIMPLE(ssa, startwith("pre")) fn2   ()
+{
+  int b_lsm6;
+  int j;
+  int c0_1;
+  int iftmp2_8;
+
+  __BB(2):
+  a = _Literal (unsigned)30;
+  c0_1 = c;
+  b_lsm6_9 = b;
+  goto __BB7;
+
+  __BB(3):
+  if (j_6(D) != 2147483647)
+    goto __BB4;
+  else
+    goto __BB5;
+
+  __BB(4):
+  iftmp2_8 = j_6(D) + 1;
+  goto __BB5;
+
+  __BB(5):
+  b_lsm6_10 = 2147483647;
+  goto __BB6;
+
+  __BB(6):
+  if (c0_1 != 0)
+    goto __BB3;
+  else
+    goto __BB8;
+
+  __BB(8):
+  goto __BB7;
+
+  __BB(7):
+  goto __BB6;
+
+}
+
+#if 0
+/* This used to be a C based testcase but ccp3 would now would remove
+   the setting of iftmp2_8 (in the above gimple) which would cause PRE
+   not to test what PRE was doing incorrectly. The original code is below. */
 /* Disable tree-evrp because the new version of evrp sees
 <bb 3> :
   if (j_8(D) != 2147483647)
@@ -18,14 +71,6 @@ which causes the situation being tested to dissapear before we get to PRE.  */
 
 /* Likewise disable DSE which also elides the tail merging "opportunity".  */
 
-#if __SIZEOF_INT__ == 2
-#define unsigned __UINT32_TYPE__
-#define int __INT32_TYPE__
-#endif
-
-unsigned a;
-int b, c;
-
 static int
 fn1 (int p1, int p2)
 {
@@ -41,5 +86,6 @@ fn2 (void)
     for (; c; b = fn1 (j, 1))
       ;
 }
+#endif
 
 /* { dg-final { scan-tree-dump-times "(?n)find_duplicates: <bb .*> duplicate of <bb .*>" 1 "pre" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/evrp7.c b/gcc/testsuite/gcc.dg/tree-ssa/evrp7.c
index 16fbe65e4d9..07314304bcf 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/evrp7.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/evrp7.c
@@ -11,4 +11,4 @@ int test1(int i, int k)
   return 1;
 }
 
-/* { dg-final { scan-tree-dump "Removing dead stmt \[^\r\n\]* = j_.* == 10" "evrp" } } */
+/* { dg-final { scan-tree-dump "Removing dead stmt:\[^\r\n\]* = j_.* == 10" "evrp" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/evrp8.c b/gcc/testsuite/gcc.dg/tree-ssa/evrp8.c
index b7e5c7aa2de..a968346fea6 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/evrp8.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/evrp8.c
@@ -8,4 +8,4 @@ int foo(int i)
   return 1;
 }
 
-/* { dg-final { scan-tree-dump "Removing dead stmt \[^\r\n\]* = i_.* == 1" "evrp" } } */
+/* { dg-final { scan-tree-dump "Removing dead stmt:\[^\r\n\]* = i_.* == 1" "evrp" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr98737-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr98737-1.c
index e313a7fa79d..8e105b46a8b 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr98737-1.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr98737-1.c
@@ -2,8 +2,11 @@
 /* { dg-do compile { target i?86-*-* x86_64-*-* powerpc*-*-* aarch64*-*-* } } */
 /* { dg-options "-O2 -fdump-tree-optimized -fcompare-debug" } */
 /* { dg-additional-options "-march=i686" { target ia32 } } */
-/* { dg-final { scan-tree-dump-not "__atomic_fetch_" "optimized" } } */
-/* { dg-final { scan-tree-dump-not "__sync_fetch_and_" "optimized" } } */
+/* Note the choice between __atomic_fetch_and_* and __atomic_and_*_fetch
+   if the result is not used does not matter. so check if make sure we don't
+   have __atomic_fetch_ with an assignment */
+/* { dg-final { scan-tree-dump-not "= __atomic_fetch_" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "= __sync_fetch_and_" "optimized" } } */
 
 typedef signed char schar;
 typedef unsigned long ulong;
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp35.c b/gcc/testsuite/gcc.dg/tree-ssa/vrp35.c
index a372a18cc43..1d76677bd3d 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/vrp35.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp35.c
@@ -11,4 +11,4 @@ int test1(int i, int k)
   return 1;
 }
 
-/* { dg-final { scan-tree-dump "Removing dead stmt \[^\r\n\]* = j_.* == 10" "vrp1" } } */
+/* { dg-final { scan-tree-dump "Removing dead stmt:\[^\r\n\]* = j_.* == 10" "vrp1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/vrp36.c b/gcc/testsuite/gcc.dg/tree-ssa/vrp36.c
index 1f77b539d70..1e9c7f424bb 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/vrp36.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/vrp36.c
@@ -8,4 +8,4 @@ int foo(int i)
   return 1;
 }
 
-/* { dg-final { scan-tree-dump "Removing dead stmt \[^\r\n\]* = i_.* == 1" "vrp1" } } */
+/* { dg-final { scan-tree-dump "Removing dead stmt:\[^\r\n\]* = i_.* == 1" "vrp1" } } */
diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
index e4c32e630df..6554b5db03e 100644
--- a/gcc/tree-ssa-dce.cc
+++ b/gcc/tree-ssa-dce.cc
@@ -2097,7 +2097,7 @@ make_pass_cd_dce (gcc::context *ctxt)
    use operands number.  */
 
 void
-simple_dce_from_worklist (bitmap worklist)
+simple_dce_from_worklist (bitmap worklist, bitmap need_eh_cleanup)
 {
   int phiremoved = 0;
   int stmtremoved = 0;
@@ -2127,6 +2127,11 @@ simple_dce_from_worklist (bitmap worklist)
       if (stmt_unremovable_because_of_non_call_eh_p (cfun, t))
 	continue;
 
+      /* Tell the caller that we removed a statement that might
+	 throw so it could cleanup the cfg for that block. */
+      if (need_eh_cleanup && stmt_could_throw_p (cfun, t))
+	bitmap_set_bit (need_eh_cleanup, gimple_bb (t)->index);
+
       /* Add uses to the worklist.  */
       ssa_op_iter iter;
       use_operand_p use_p;
diff --git a/gcc/tree-ssa-dce.h b/gcc/tree-ssa-dce.h
index f2542157608..5522359f5b2 100644
--- a/gcc/tree-ssa-dce.h
+++ b/gcc/tree-ssa-dce.h
@@ -18,5 +18,5 @@ along with GCC; see the file COPYING3.  If not see
 
 #ifndef TREE_SSA_DCE_H
 #define TREE_SSA_DCE_H
-extern void simple_dce_from_worklist (bitmap);
+extern void simple_dce_from_worklist (bitmap, bitmap = nullptr);
 #endif
diff --git a/gcc/tree-ssa-propagate.cc b/gcc/tree-ssa-propagate.cc
index 76708ca185f..5573d360699 100644
--- a/gcc/tree-ssa-propagate.cc
+++ b/gcc/tree-ssa-propagate.cc
@@ -38,6 +38,7 @@
 #include "cfgloop.h"
 #include "tree-cfgcleanup.h"
 #include "cfganal.h"
+#include "tree-ssa-dce.h"
 
 /* This file implements a generic value propagation engine based on
    the same propagation used by the SSA-CCP algorithm [1].
@@ -527,7 +528,6 @@ struct prop_stats_d
   long num_const_prop;
   long num_copy_prop;
   long num_stmts_folded;
-  long num_dce;
 };
 
 static struct prop_stats_d prop_stats;
@@ -641,14 +641,14 @@ public:
           something_changed (false),
 	  substitute_and_fold_engine (engine)
     {
-      stmts_to_remove.create (0);
+      dceworklist = BITMAP_ALLOC (NULL);
       stmts_to_fixup.create (0);
       need_eh_cleanup = BITMAP_ALLOC (NULL);
       need_ab_cleanup = BITMAP_ALLOC (NULL);
     }
     ~substitute_and_fold_dom_walker ()
     {
-      stmts_to_remove.release ();
+      BITMAP_FREE (dceworklist);
       stmts_to_fixup.release ();
       BITMAP_FREE (need_eh_cleanup);
       BITMAP_FREE (need_ab_cleanup);
@@ -661,7 +661,7 @@ public:
     }
 
     bool something_changed;
-    vec<gimple *> stmts_to_remove;
+    bitmap dceworklist;
     vec<gimple *> stmts_to_fixup;
     bitmap need_eh_cleanup;
     bitmap need_ab_cleanup;
@@ -760,7 +760,7 @@ substitute_and_fold_dom_walker::before_dom_children (basic_block bb)
 		  print_generic_expr (dump_file, sprime);
 		  fprintf (dump_file, "\n");
 		}
-	      stmts_to_remove.safe_push (phi);
+	      bitmap_set_bit (dceworklist, SSA_NAME_VERSION (res));
 	      continue;
 	    }
 	}
@@ -802,7 +802,7 @@ substitute_and_fold_dom_walker::before_dom_children (basic_block bb)
 		  print_generic_expr (dump_file, sprime);
 		  fprintf (dump_file, "\n");
 		}
-	      stmts_to_remove.safe_push (stmt);
+	      bitmap_set_bit (dceworklist, SSA_NAME_VERSION (lhs));
 	      continue;
 	    }
 	}
@@ -970,30 +970,7 @@ substitute_and_fold_engine::substitute_and_fold (basic_block block)
   substitute_and_fold_dom_walker walker (CDI_DOMINATORS, this);
   walker.walk (block ? block : ENTRY_BLOCK_PTR_FOR_FN (cfun));
 
-  /* We cannot remove stmts during the BB walk, especially not release
-     SSA names there as that destroys the lattice of our callers.
-     Remove stmts in reverse order to make debug stmt creation possible.  */
-  while (!walker.stmts_to_remove.is_empty ())
-    {
-      gimple *stmt = walker.stmts_to_remove.pop ();
-      if (dump_file && dump_flags & TDF_DETAILS)
-	{
-	  fprintf (dump_file, "Removing dead stmt ");
-	  print_gimple_stmt (dump_file, stmt, 0);
-	  fprintf (dump_file, "\n");
-	}
-      prop_stats.num_dce++;
-      gimple_stmt_iterator gsi = gsi_for_stmt (stmt);
-      if (gimple_code (stmt) == GIMPLE_PHI)
-	remove_phi_node (&gsi, true);
-      else
-	{
-	  unlink_stmt_vdef (stmt);
-	  gsi_remove (&gsi, true);
-	  release_defs (stmt);
-	}
-    }
-
+  simple_dce_from_worklist (walker.dceworklist, walker.need_eh_cleanup);
   if (!bitmap_empty_p (walker.need_eh_cleanup))
     gimple_purge_all_dead_eh_edges (walker.need_eh_cleanup);
   if (!bitmap_empty_p (walker.need_ab_cleanup))
@@ -1021,8 +998,6 @@ substitute_and_fold_engine::substitute_and_fold (basic_block block)
 			    prop_stats.num_copy_prop);
   statistics_counter_event (cfun, "Statements folded",
 			    prop_stats.num_stmts_folded);
-  statistics_counter_event (cfun, "Statements deleted",
-			    prop_stats.num_dce);
 
   return walker.something_changed;
 }
-- 
2.39.1