Fix PR42640: Correctly initialize the value of the new induction variable.

2010-03-02  Reza Yazdani  <reza.yazdani@amd.com>

	PR middle-end/42640
	* tree-loop-distribution.c (update_phis_for_loop_copy): Replaced
	the assignment from the new induction variable to the assignment
	of the value from the original loop PHI function.

	* gcc.dg/tree-ssa/pr42640.c: New.

From-SVN: r157161

4 files changed, 75 insertions, 5 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 47e217f..9e9755a 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2010-03-02  Reza Yazdani  <reza.yazdani@amd.com>
+
+	PR middle-end/42640
+	* tree-loop-distribution.c (update_phis_for_loop_copy): Replaced
+	the assignment from the new induction variable to the assignment
+	of the value from the original loop PHI function.
+
 2010-03-01  Janis Johnson  <janis187@us.ibm.com>
 	    Daniel Jacobowitz  <dan@codesourcery.com>
 
@@ -27,7 +34,7 @@
 2010-03-01  Christian Bruel  <christian.bruel@st.com>
 
 	* except.c (dw2_build_landing_pads): set LABEL_PRESERVE_P.
-	
+
 2010-03-01  H.J. Lu  <hongjiu.lu@intel.com>
 
 	* config/i386/linux64.h (ASM_SPEC): Use SPEC_32 and SPEC_64.
@@ -47,7 +54,7 @@
 	64-bit, SPARC and x86.
 	(sol_gt_pch_get_address): New function.
 
-2010-03-01  Marco Poletti  <poletti.marco@gmail.com> 
+2010-03-01  Marco Poletti  <poletti.marco@gmail.com>
 
 	* toplev.h (inform_n, error_n): Declare.
 	* diagnostic.c (inform_n, error_n): New function.
@@ -133,7 +140,7 @@
 	* doc/standards.texi: Likewise.
 	* doc/extend.texi: Likewise.
 	* doc/trouble.texi: Likewise.
-	* doc/cppopts.texi: Likewise. 
+	* doc/cppopts.texi: Likewise.
 	* doc/install.texi: Likewise.
 	* c.opt (std=c90,std=gnu90): New options.
 	* c-opts.c (c_common_handle_option): Handle them.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 6e72856..63ceb9a 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2010-03-02  Reza Yazdani  <reza.yazdani@amd.com>
+
+	PR middle-end/42640
+	* gcc.dg/tree-ssa/pr42640.c: New.
+
 2010-03-01  Richard Guenther  <rguenther@suse.de>
 
 	PR tree-optimization/43220
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr42640.c b/gcc/testsuite/gcc.dg/tree-ssa/pr42640.c
new file mode 100644
index 0000000..70807c0
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr42640.c
@@ -0,0 +1,58 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -ftree-loop-distribution" } */
+
+/* Checks if loop distribution works correctly if the subscript used
+   is assigned to a loop invariant value.  */
+
+extern void abort (void);
+struct S { int a; int b; int c; };
+
+int get_rr_node_index (int i)
+{
+  return i;
+}
+
+struct S nodes[8];
+struct S *rr_node = nodes;
+volatile int io_rat = 2;
+void
+doit (int i, int j)
+{
+  int s_node, p_node, inode, ipad, iloop;
+
+  for (ipad = 0; ipad < io_rat; ipad++)
+    {
+      p_node = get_rr_node_index (ipad+2);
+      inode = get_rr_node_index (ipad);
+
+      for (iloop = 1; iloop <= 2; iloop++)
+	{
+	  rr_node[inode].a = i;
+	  rr_node[inode].b = j;
+	  rr_node[inode].c = ipad;
+	  inode = p_node;
+	}
+    }
+}
+
+int
+main ()
+{
+  int i;
+
+  doit (1, 2);
+
+  if (rr_node[0].a != rr_node[1].a
+      || rr_node[2].a != rr_node[3].a
+      || rr_node[1].a != 1
+      || rr_node[0].b != rr_node[1].b
+      || rr_node[2].b != rr_node[3].b
+      || rr_node[1].b != 2
+      || rr_node[0].c != 0
+      || rr_node[1].c != 1
+      || rr_node[2].c != 0
+      || rr_node[3].c != 1)
+    abort ();
+
+  return 0;
+}
diff --git a/gcc/tree-loop-distribution.c b/gcc/tree-loop-distribution.c
index 13ac7ea..920ab8c 100644
--- a/gcc/tree-loop-distribution.c
+++ b/gcc/tree-loop-distribution.c
@@ -118,8 +118,8 @@ update_phis_for_loop_copy (struct loop *orig_loop, struct loop *new_loop)
 
 	  if (!new_ssa_name)
 	    /* This only happens if there are no definitions inside the
-	       loop.  Use the phi_result in this case.  */
-	    new_ssa_name = PHI_RESULT (phi_new);
+	       loop.  Use the the invariant in the new loop as is.  */
+	    new_ssa_name = def;
 	}
       else
 	/* Could be an integer.  */