re PR tree-optimization/87977 (ICE: verify_ssa failed (error: definition in…

re PR tree-optimization/87977 (ICE: verify_ssa failed (error: definition in block 4 follows the use))

	PR tree-optimization/87977
	* tree-ssa-math-opts.c (optimize_recip_sqrt): Don't reuse division
	stmt, build a new one and replace the old one with it.  Formatting fix.
	Call release_ssa_name (x) if !has_other_use and !delete_div.
	(pass_cse_reciprocals::execute): Before calling optimize_recip_sqrt
	verify lhs of stmt is still def.

	* gcc.dg/recip_sqrt_mult_1.c: Add -fcompare-debug to dg-options.
	* gcc.dg/recip_sqrt_mult_2.c: Likewise.
	* gcc.dg/recip_sqrt_mult_3.c: Likewise.
	* gcc.dg/recip_sqrt_mult_4.c: Likewise.
	* gcc.dg/recip_sqrt_mult_5.c: Likewise.

From-SVN: r266098

gcc/ChangeLog

+2018-11-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/87977
+	* tree-ssa-math-opts.c (optimize_recip_sqrt): Don't reuse division
+	stmt, build a new one and replace the old one with it.  Formatting fix.
+	Call release_ssa_name (x) if !has_other_use and !delete_div.
+	(pass_cse_reciprocals::execute): Before calling optimize_recip_sqrt
+	verify lhs of stmt is still def.
+
 2018-11-13  Peter Bergner  <bergner@linux.ibm.com>
 
 	PR rtl-optimization/87507

gcc/testsuite/ChangeLog

+2018-11-14  Jakub Jelinek  <jakub@redhat.com>
+
+	PR tree-optimization/87977
+	* gcc.dg/recip_sqrt_mult_1.c: Add -fcompare-debug to dg-options.
+	* gcc.dg/recip_sqrt_mult_2.c: Likewise.
+	* gcc.dg/recip_sqrt_mult_3.c: Likewise.
+	* gcc.dg/recip_sqrt_mult_4.c: Likewise.
+	* gcc.dg/recip_sqrt_mult_5.c: Likewise.
+
 2018-11-13  Peter Bergner  <bergner@linux.ibm.com>
 
 	PR rtl-optimization/87507

gcc/testsuite/gcc.dg/recip_sqrt_mult_1.c

 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-recip" } */
+/* { dg-options "-Ofast -fdump-tree-recip -fcompare-debug" } */
 
 double res, res2, tmp;
 void

gcc/testsuite/gcc.dg/recip_sqrt_mult_2.c

 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-optimized" } */
+/* { dg-options "-Ofast -fdump-tree-optimized -fcompare-debug" } */
 
 float
 foo (float a)

gcc/testsuite/gcc.dg/recip_sqrt_mult_3.c

 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-optimized" } */
+/* { dg-options "-Ofast -fdump-tree-optimized -fcompare-debug" } */
 
 double
 foo (double a)

gcc/testsuite/gcc.dg/recip_sqrt_mult_4.c

 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-recip" } */
+/* { dg-options "-Ofast -fdump-tree-recip -fcompare-debug" } */
 
 /* The main path doesn't have any multiplications.
    Avoid introducing them in the recip pass.  */

gcc/testsuite/gcc.dg/recip_sqrt_mult_5.c

 /* { dg-do compile } */
-/* { dg-options "-Ofast -fdump-tree-recip" } */
+/* { dg-options "-Ofast -fdump-tree-recip -fcompare-debug" } */
 
 /* We want to do the recip_sqrt transformations here there is already
    a multiplication on the main path.  */

gcc/tree-ssa-math-opts.c

@@ -652,8 +652,12 @@ optimize_recip_sqrt (gimple_stmt_iterator *def_gsi, tree def)
 	  print_gimple_stmt (dump_file, stmt, 0, TDF_NONE);
 	  fprintf (dump_file, "with new division\n");
 	}
-      gimple_assign_set_lhs (stmt, sqr_ssa_name);
-      gimple_assign_set_rhs2 (stmt, a);
+      stmt
+	= gimple_build_assign (sqr_ssa_name, gimple_assign_rhs_code (stmt),
+			       gimple_assign_rhs1 (stmt), a);
+      gsi_insert_before (def_gsi, stmt, GSI_SAME_STMT);
+      gsi_remove (def_gsi, true);
+      *def_gsi = gsi_for_stmt (stmt);
       fold_stmt_inplace (def_gsi);
       update_stmt (stmt);
 
@@ -704,7 +708,7 @@ optimize_recip_sqrt (gimple_stmt_iterator *def_gsi, tree def)
 
       gimple *new_stmt
 	= gimple_build_assign (x, MULT_EXPR,
-				orig_sqrt_ssa_name, sqr_ssa_name);
+			       orig_sqrt_ssa_name, sqr_ssa_name);
       gsi_insert_after (def_gsi, new_stmt, GSI_NEW_STMT);
       update_stmt (stmt);
     }
@@ -715,6 +719,8 @@ optimize_recip_sqrt (gimple_stmt_iterator *def_gsi, tree def)
       gsi_remove (&gsi2, true);
       release_defs (stmt);
     }
+  else
+    release_ssa_name (x);
 }
 
 /* Look for floating-point divisions among DEF's uses, and try to
@@ -951,6 +957,7 @@ pass_cse_reciprocals::execute (function *fun)
 	      stmt = gsi_stmt (gsi);
 	      if (flag_unsafe_math_optimizations
 		  && is_gimple_assign (stmt)
+		  && gimple_assign_lhs (stmt) == def
 		  && !stmt_can_throw_internal (cfun, stmt)
 		  && gimple_assign_rhs_code (stmt) == RDIV_EXPR)
 		optimize_recip_sqrt (&gsi, def);