Handle equal-argument loop exit phi in expand_omp_for_static_chunk

2017-07-18  Tom de Vries  <tom@codesourcery.com>

	PR middle-end/81464
	* omp-expand.c (expand_omp_for_static_chunk): Handle equal-argument loop
	exit phi.

	* gfortran.dg/pr81464.f90: New test.

From-SVN: r250335

gcc/ChangeLog

+2017-07-18  Tom de Vries  <tom@codesourcery.com>
+
+	PR middle-end/81464
+	* omp-expand.c (expand_omp_for_static_chunk): Handle equal-argument loop
+	exit phi.
+
 2017-07-18  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/81471

gcc/omp-expand.c

@@ -4206,6 +4206,10 @@ expand_omp_for_static_chunk (struct omp_region *region,
 	  source_location locus;
 
 	  phi = psi.phi ();
+	  if (operand_equal_p (gimple_phi_arg_def (phi, 0),
+			       redirect_edge_var_map_def (vm), 0))
+	    continue;
+
 	  t = gimple_phi_result (phi);
 	  gcc_assert (t == redirect_edge_var_map_result (vm));
 

gcc/testsuite/ChangeLog

+2017-07-18  Tom de Vries  <tom@codesourcery.com>
+
+	PR middle-end/81464
+	* gfortran.dg/pr81464.f90: New test.
+
 2017-07-18  Uros Bizjak  <ubizjak@gmail.com>
 
 	PR target/81471

gcc/testsuite/gfortran.dg/pr81464.f90

+! { dg-do compile }
+! { dg-options "--param parloops-chunk-size=2 -ftree-parallelize-loops=2 -O1" }
+
+program main
+  implicit none
+  real, dimension(:,:),allocatable :: a, b, c
+  real :: sm
+
+  allocate (a(2,2), b(2,2), c(2,2))
+
+  call random_number(a)
+  call random_number(b)
+
+  c = matmul(a,b)
+  sm = sum(c)
+
+  deallocate(a,b,c)
+
+end program main