[PATCH] Fix PR57214

[Richard Biener]

This fixes PR57214 - the simple constant propagation pass we perform
over unrolled loop bodies does not properly avoid propagating across
abnormal edges.

Bootstrap & regtest running on x86_64-unknown-linux-gnu, I'll install
this on trunk and the 4.8 branch where the bug is latent.

Richard.

2013-05-10  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/57214
        * tree-ssa-loop-ivcanon.c (propagate_constants_for_unrolling): Do
        not propagate from SSA names that occur in abnormal PHI nodes.

Index: gcc/tree-ssa-loop-ivcanon.c
===================================================================
*** gcc/tree-ssa-loop-ivcanon.c (revision 198768)
--- gcc/tree-ssa-loop-ivcanon.c (working copy)
*************** propagate_constants_for_unrolling (basic
*** 1085,1092 ****
        tree lhs;
  
        if (is_gimple_assign (stmt)
          && (lhs = gimple_assign_lhs (stmt), TREE_CODE (lhs) == SSA_NAME)
!         && gimple_assign_rhs_code (stmt) == INTEGER_CST)
        {
          propagate_into_all_uses (lhs, gimple_assign_rhs1 (stmt));
          gsi_remove (&gsi, true);
--- 1085,1093 ----
        tree lhs;
  
        if (is_gimple_assign (stmt)
+         && gimple_assign_rhs_code (stmt) == INTEGER_CST
          && (lhs = gimple_assign_lhs (stmt), TREE_CODE (lhs) == SSA_NAME)
!         && !SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
        {
          propagate_into_all_uses (lhs, gimple_assign_rhs1 (stmt));
          gsi_remove (&gsi, true);
Index: gcc/testsuite/gcc.dg/torture/pr57214.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr57214.c      (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr57214.c      (working copy)
***************
*** 0 ****
--- 1,25 ----
+ /* { dg-do compile } */
+ 
+ extern int baz (void);
+ extern int foo (void) __attribute__ ((returns_twice));
+ 
+ void
+ bar (_Bool b)
+ {
+   int buf[1];
+   while (1)
+     {
+       _Bool x = 1;
+       if (b)
+       baz ();
+       b = 1;
+       baz ();
+       x = 0;
+       int i;
+       while (buf[i] && i)
+       i++;
+       foo ();
+       if (!x)
+       b = 0;
+     }
+ }