re PR tree-optimization/86489 (ICE in gimple_phi_arg starting with r261682 when…

re PR tree-optimization/86489 (ICE in gimple_phi_arg starting with r261682 when building 531.deepsjeng_r with FDO + LTO)

gcc/ChangeLog:

2018-07-13  Kugan Vivekanandarajah  <kuganv@linaro.org>
	    Richard Biener  <rguenther@suse.de>

	PR middle-end/86489
	* tree-ssa-loop-niter.c (number_of_iterations_popcount): Check
	that the loop latch destination where phi is defined.

gcc/testsuite/ChangeLog:

2018-07-13  Kugan Vivekanandarajah  <kuganv@linaro.org>

	PR middle-end/86489
	* gcc.dg/pr86489.c: New test.


Co-Authored-By: Richard Biener <rguenther@suse.de>

From-SVN: r262622

gcc/ChangeLog

+2018-07-13  Kugan Vivekanandarajah  <kuganv@linaro.org>
+	    Richard Biener  <rguenther@suse.de>
+
+	PR middle-end/86489
+	* tree-ssa-loop-niter.c (number_of_iterations_popcount): Check
+	that the loop latch destination where phi is defined.
+
 2018-07-12  Kito Cheng  <kito.cheng@gmail.com>
 
         * config/riscv/riscv.c (enum riscv_privilege_levels): Add UNKNOWN_MODE.

gcc/testsuite/ChangeLog

+2018-07-13  Kugan Vivekanandarajah  <kuganv@linaro.org>
+
+	PR middle-end/86489
+	* gcc.dg/pr86489.c: New test.
+
 2018-07-12  Martin Sebor  <msebor@redhat.com>
 
 	PR testsuite/86510

gcc/testsuite/gcc.dg/pr86489.c

+
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+int a = 0, b = 0;
+void fn1() {
+    int c = 0;
+    for (; a; a--)
+      c += b;
+    while ((c - 1) & c)
+      ;
+}

gcc/tree-ssa-loop-niter.c

@@ -2555,6 +2555,7 @@ number_of_iterations_popcount (loop_p loop, edge exit,
    ... = PHI <b_5(2), b_6(3)>.  */
   gimple *phi = SSA_NAME_DEF_STMT (b_11);
   if (gimple_code (phi) != GIMPLE_PHI
+      || (gimple_bb (phi) != loop_latch_edge (loop)->dest)
       || (gimple_assign_lhs (and_stmt)
 	  != gimple_phi_arg_def (phi, loop_latch_edge (loop)->dest_idx)))
     return false;