re PR tree-optimization/56962 (SLSR caused miscompilation of fftw)

	PR tree-optimization/56962
	* gimple-ssa-strength-reduction.c (record_increment): Only set
	initializer if gimple_assign_rhs_code is {,POINTER_}PLUS_EXPR and
	either rhs1 or rhs2 is equal to c->base_expr.

	* gcc.c-torture/execute/pr56962.c: New test.

From-SVN: r197978

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index db1b37325b45a674f1c851bb59b00727b7b6f6f8..58f811efd80a9bf21ef87ec7bb967ca862a6d009 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2013-04-15  Jakub Jelinek  <jakub@redhat.com>
+
+       PR tree-optimization/56962
+       * gimple-ssa-strength-reduction.c (record_increment): Only set
+       initializer if gimple_assign_rhs_code is {,POINTER_}PLUS_EXPR and
+       either rhs1 or rhs2 is equal to c->base_expr.
+
 2013-04-15  Richard Biener  <rguenther@suse.de>
 
        PR tree-optimization/56933

diff --git a/gcc/gimple-ssa-strength-reduction.c b/gcc/gimple-ssa-strength-reduction.c
index 873b8bcd7e91898cb67f352f76ab883a724ebe63..57b343ab5cf78167c42850f7faec46588b76f39f 100644 (file)
--- a/gcc/gimple-ssa-strength-reduction.c
+++ b/gcc/gimple-ssa-strength-reduction.c
@@ -1829,16 +1829,20 @@ record_increment (slsr_cand_t c, double_int increment)
       if (c->kind == CAND_ADD
          && c->index == increment
          && (increment.sgt (double_int_one)
-             || increment.slt (double_int_minus_one)))
+             || increment.slt (double_int_minus_one))
+         && (gimple_assign_rhs_code (c->cand_stmt) == PLUS_EXPR
+             || gimple_assign_rhs_code (c->cand_stmt) == POINTER_PLUS_EXPR))
        {
-         tree t0;
+         tree t0 = NULL_TREE;
          tree rhs1 = gimple_assign_rhs1 (c->cand_stmt);
          tree rhs2 = gimple_assign_rhs2 (c->cand_stmt);
          if (operand_equal_p (rhs1, c->base_expr, 0))
            t0 = rhs2;
-         else
+         else if (operand_equal_p (rhs2, c->base_expr, 0))
            t0 = rhs1;
-         if (SSA_NAME_DEF_STMT (t0) && gimple_bb (SSA_NAME_DEF_STMT (t0)))
+         if (t0
+             && SSA_NAME_DEF_STMT (t0)
+             && gimple_bb (SSA_NAME_DEF_STMT (t0)))
            {
              incr_vec[incr_vec_len].initializer = t0;
              incr_vec[incr_vec_len++].init_bb

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 46135933624725768fbb9cdb20ea6ec35e5b8d03..af446d7a752d179fff49e0d25c5a7b63dcdfa503 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2013-04-15  Jakub Jelinek  <jakub@redhat.com>
+
+       PR tree-optimization/56962
+       * gcc.c-torture/execute/pr56962.c: New test.
+
 2013-04-15  Richard Biener  <rguenther@suse.de>
 
        PR tree-optimization/56933

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr56962.c b/gcc/testsuite/gcc.c-torture/execute/pr56962.c
new file mode 100644 (file)
index 0000000..7c6da48
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr56962.c
@@ -0,0 +1,30 @@
+/* PR tree-optimization/56962 */
+
+extern void abort (void);
+long long v[144];
+
+__attribute__((noinline, noclone)) void
+bar (long long *x)
+{
+  if (x != &v[29])
+    abort ();
+}
+
+__attribute__((noinline, noclone)) void
+foo (long long *x, long y, long z)
+{
+  long long a, b, c;
+  a = x[z * 4 + y * 3];
+  b = x[z * 5 + y * 3];
+  c = x[z * 5 + y * 4];
+  x[y * 4] = a;
+  bar (&x[z * 5 + y]);
+  x[z * 5 + y * 5] = b + c;
+}
+
+int
+main ()
+{
+  foo (v, 24, 1);
+  return 0;
+}