[tree-ssa-mathopts] PR tree-optimization/87259: Call execute_cse_reciprocals_1…

[tree-ssa-mathopts] PR tree-optimization/87259: Call execute_cse_reciprocals_1 before trying optimize_recip_sqrt

	PR tree-optimization/87259
	PR lto/87283
	(pass_cse_reciprocals::execute): Run optimize_recip_sqrt after
	execute_cse_reciprocals_1 has tried transforming.

	PR tree-optimization/87259
	* gcc.dg/pr87259.c: New test.

From-SVN: r264312

gcc/ChangeLog

+2018-09-14  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR tree-optimization/87259
+	PR lto/87283
+	(pass_cse_reciprocals::execute): Run optimize_recip_sqrt after
+	execute_cse_reciprocals_1 has tried transforming.
+
 2018-09-14  Aldy Hernandez  <aldyh@redhat.com>
 
 	* tree-vrp.c (extract_range_from_binary_expr_1): Normalize

gcc/testsuite/ChangeLog

+2018-09-14  Kyrylo Tkachov  <kyrylo.tkachov@arm.com>
+
+	PR tree-optimization/87259
+	* gcc.dg/pr87259.c: New test.
+
 2018-09-13  Martin Sebor  <msebor@redhat.com>
 	    Jeff Law  <law@redhat.com>
 

gcc/testsuite/gcc.dg/pr87259.c

+/* { dg-do compile } */
+/* { dg-options "-Ofast" } */
+
+int a, b, c;
+int *e;
+float f;
+void h() {
+  for (int g;;) {
+    float d = b, i = 0 / f, j = a / (f * f), k, l = 0 / d;
+    c = i + j;
+    g = l;
+    e[g] = c / d * k / d;
+  }
+}

gcc/tree-ssa-math-opts.c

@@ -547,7 +547,7 @@ free_bb (struct occurrence *occ)
    depending on the uses of x, r1, r2.  This removes one multiplication and
    allows the sqrt and division operations to execute in parallel.
    DEF_GSI is the gsi of the initial division by sqrt that defines
-   DEF (x in the example abovs).  */
+   DEF (x in the example above).  */
 
 static void
 optimize_recip_sqrt (gimple_stmt_iterator *def_gsi, tree def)
@@ -947,13 +947,13 @@ pass_cse_reciprocals::execute (function *fun)
 	      && FLOAT_TYPE_P (TREE_TYPE (def))
 	      && TREE_CODE (def) == SSA_NAME)
 	    {
+	      execute_cse_reciprocals_1 (&gsi, def);
+	      stmt = gsi_stmt (gsi);
 	      if (flag_unsafe_math_optimizations
 		  && is_gimple_assign (stmt)
 		  && !stmt_can_throw_internal (stmt)
 		  && gimple_assign_rhs_code (stmt) == RDIV_EXPR)
 		optimize_recip_sqrt (&gsi, def);
-	      else
-		execute_cse_reciprocals_1 (&gsi, def);
 	    }
 	}