re PR tree-optimization/81987 (ICE in verify_ssa with -O3 -march=skylake-avx512)

[gcc]

2017-08-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/81987
	* gimple-ssa-strength-reduction.c (insert_initializers): Don't
	insert an initializer in a location not dominated by the stride
	definition.

[gcc/testsuite]

2017-08-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>

	PR tree-optimization/81987
	* g++.dg/torture/pr81987.C: New file.

From-SVN: r251547

4 files changed, 90 insertions, 0 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 9106eb73..379be0a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2017-08-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR tree-optimization/81987
+	* gimple-ssa-strength-reduction.c (insert_initializers): Don't
+	insert an initializer in a location not dominated by the stride
+	definition.
+
 2017-08-30  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* tree-eh.c (lower_try_finally_switch): Set the location of the finally
diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c
index 8fe7c17..6e3e93d 100644
--- a/gcc/gimple-ssa-strength-reduction.c
+++ b/gcc/gimple-ssa-strength-reduction.c
@@ -3340,6 +3340,23 @@ insert_initializers (slsr_cand_t c)
 	 that block, the earliest one will be returned in WHERE.  */
       bb = nearest_common_dominator_for_cands (c, incr, &where);
 
+      /* If the NCD is not dominated by the block containing the
+	 definition of the stride, we can't legally insert a
+	 single initializer.  Mark the increment as unprofitable
+	 so we don't make any replacements.  FIXME: Multiple
+	 initializers could be placed with more analysis.  */
+      gimple *stride_def = SSA_NAME_DEF_STMT (c->stride);
+      basic_block stride_bb = gimple_bb (stride_def);
+
+      if (stride_bb && !dominated_by_p (CDI_DOMINATORS, bb, stride_bb))
+	{
+	  if (dump_file && (dump_flags & TDF_DETAILS))
+	    fprintf (dump_file,
+		     "Initializer #%d cannot be legally placed\n", i);
+	  incr_vec[i].cost = COST_INFINITE;
+	  continue;
+	}
+
       /* If the nominal stride has a different type than the recorded
 	 stride type, build a cast from the nominal stride to that type.  */
       if (!types_compatible_p (TREE_TYPE (c->stride), c->stride_type))
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 0fab4d4..afaa919 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2017-08-30  Bill Schmidt  <wschmidt@linux.vnet.ibm.com>
+
+	PR tree-optimization/81987
+	* g++.dg/torture/pr81987.C: New file.
+
 2017-08-30  Eric Botcazou  <ebotcazou@adacore.com>
 
 	* gnat.dg/aggr22.ad[sb]: New test.
diff --git a/gcc/testsuite/g++.dg/torture/pr81987.C b/gcc/testsuite/g++.dg/torture/pr81987.C
new file mode 100644
index 0000000..4579332
--- /dev/null
+++ b/gcc/testsuite/g++.dg/torture/pr81987.C
@@ -0,0 +1,61 @@
+extern short var_1;
+extern const short var_3;
+extern unsigned long int var_9;
+extern short var_13;
+extern const unsigned long int var_15;
+extern const unsigned long int var_37;
+extern unsigned long int var_40;
+extern long long int var_47;
+extern short var_48;
+extern const short var_54;
+extern long long int var_79;
+extern long long int var_81;
+extern long long int var_94;
+extern long long int var_95;
+extern long long int var_701;
+extern unsigned long int var_786;
+extern short var_788;
+extern long long int var_844;
+
+struct struct_1 {
+  short member_1_2 : 15;
+  static long long int member_1_3;
+};
+
+extern struct_1 struct_obj_6;
+extern struct_1 struct_obj_8;
+
+void foo() {
+  int a = var_3 <= 602154393864UL;
+  if (var_81 ? 0 : var_3 && var_9)
+    ;
+  else {
+    var_94 = 0;
+    if (var_3 && var_48 || var_13) {
+      if (var_48)
+	var_95 = 0;
+      short b((2364461588881776511UL + var_3) * (2 ? var_13 : 0) || var_1);
+      struct_obj_8.member_1_2 = b;
+      if (var_15) {
+	if (var_81)
+	  if (var_47)
+	    ;
+	  else if (var_40)
+	    var_701 = 0;
+      } else {
+	if (var_40)
+	  var_79 = 0;
+	if (var_54) {
+	  if (var_37)
+	    var_786 = 0;
+	  else
+	    var_788 = 0;
+	            struct_obj_6.member_1_3 =
+		      (2364461588881776511UL + var_3) * (2 ? var_13 : 0);
+	}
+      }
+      if ((2364461588881776511UL + var_3) * (2 ? var_13 : 0))
+	var_844 = 0;
+    }
+  }
+}