if-conv: Fix -fcompare-debug bugs in ifcvt_local_dce [PR94283]

The following testcase shows -fcompare-debug bugs in ifcvt_local_dce,
where the decisions what statements are needed is based also on debug stmt
operands, which is wrong.
So, this patch makes sure to never add debug stmt to the worklist, or never
add an assign to worklist just because it is used in a debug stmt in another
bb.

2020-03-24  Jakub Jelinek  <jakub@redhat.com>

	PR debug/94283
	* tree-if-conv.c (ifcvt_local_dce): For gimple debug stmts, just set
	GF_PLF_2, but don't add them to worklist.  Don't add an assigment to
	worklist or set GF_PLF_2 just because it is used in a debug stmt in
	another bb.  Formatting improvements.

	* gcc.target/i386/pr94283.c: New test.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a45d7ba..51cb52d 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,11 @@
 2020-03-24  Jakub Jelinek  <jakub@redhat.com>
 
+       PR debug/94283
+       * tree-if-conv.c (ifcvt_local_dce): For gimple debug stmts, just set
+       GF_PLF_2, but don't add them to worklist.  Don't add an assigment to
+       worklist or set GF_PLF_2 just because it is used in a debug stmt in
+       another bb.  Formatting improvements.
+
        PR debug/94277
        * cgraphunit.c (check_global_declaration): For DECL_EXTERNAL and
        non-TREE_PUBLIC non-DECL_ARTIFICIAL FUNCTION_DECLs, set TREE_PUBLIC

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 13e6090..e050d15 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2020-03-24  Jakub Jelinek  <jakub@redhat.com>
 
+       PR debug/94283
+       * gcc.target/i386/pr94283.c: New test.
+
        PR debug/94277
        * gcc.dg/pr94277.c: New test.
 

diff --git a/gcc/testsuite/gcc.target/i386/pr94283.c b/gcc/testsuite/gcc.target/i386/pr94283.c
new file mode 100644 (file)
index 0000000..4982f7d
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr94283.c
@@ -0,0 +1,5 @@
+/* PR debug/94283 */
+/* { dg-do compile } */
+/* { dg-options "-O3 -fcompare-debug -mavx2" } */
+
+#include "../../gcc.dg/fold-bopcond-1.c"

diff --git a/gcc/tree-if-conv.c b/gcc/tree-if-conv.c
index 8d24c18..dd11d80 100644 (file)
--- a/gcc/tree-if-conv.c
+++ b/gcc/tree-if-conv.c
@@ -2917,9 +2917,12 @@ ifcvt_local_dce (class loop *loop)
   for (gsi = gsi_start_bb (bb); !gsi_end_p (gsi); gsi_next (&gsi))
     {
       stmt = gsi_stmt (gsi);
-      if (gimple_store_p (stmt)
-         || gimple_assign_load_p (stmt)
-         || is_gimple_debug (stmt))
+      if (is_gimple_debug (stmt))
+       {
+         gimple_set_plf (stmt, GF_PLF_2, true);
+         continue;
+       }
+      if (gimple_store_p (stmt) || gimple_assign_load_p (stmt))
        {
          gimple_set_plf (stmt, GF_PLF_2, true);
          worklist.safe_push (stmt);
@@ -2940,7 +2943,7 @@ ifcvt_local_dce (class loop *loop)
          FOR_EACH_IMM_USE_FAST (use_p, imm_iter, lhs)
            {
              stmt1 = USE_STMT (use_p);
-             if (gimple_bb (stmt1) != bb)
+             if (!is_gimple_debug (stmt1) && gimple_bb (stmt1) != bb)
                {
                  gimple_set_plf (stmt, GF_PLF_2, true);
                  worklist.safe_push (stmt);
@@ -2963,8 +2966,7 @@ ifcvt_local_dce (class loop *loop)
          if (TREE_CODE (use) != SSA_NAME)
            continue;
          stmt1 = SSA_NAME_DEF_STMT (use);
-         if (gimple_bb (stmt1) != bb
-             || gimple_plf (stmt1, GF_PLF_2))
+         if (gimple_bb (stmt1) != bb || gimple_plf (stmt1, GF_PLF_2))
            continue;
          gimple_set_plf (stmt1, GF_PLF_2, true);
          worklist.safe_push (stmt1);