PR tree-optimization/51624

	* tree-sra.c (build_ref_for_model): When replicating a chain of
	COMPONENT_REFs, stop as soon as the offset would become negative.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@182889 138bc75d-0d04-0410-961f-82ee72b054a4

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index fc64179..3d9bc63 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2012-01-04  Eric Botcazou  <ebotcazou@adacore.com>
+
+       PR tree-optimization/51624
+       * tree-sra.c (build_ref_for_model): When replicating a chain of
+       COMPONENT_REFs, stop as soon as the offset would become negative.
+
 2012-01-04  Jakub Jelinek  <jakub@redhat.com>
 
        PR debug/51695

diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
index db9b9bf..accbc1e 100644 (file)
--- a/gcc/tree-sra.c
+++ b/gcc/tree-sra.c
@@ -1520,11 +1520,16 @@ build_ref_for_model (location_t loc, tree base, HOST_WIDE_INT offset,
       do {
        tree field = TREE_OPERAND (expr, 1);
        tree cr_offset = component_ref_field_offset (expr);
-       gcc_assert (cr_offset && host_integerp (cr_offset, 1));
+       HOST_WIDE_INT bit_pos
+         = tree_low_cst (cr_offset, 1) * BITS_PER_UNIT
+             + TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field));
 
-       offset -= TREE_INT_CST_LOW (cr_offset) * BITS_PER_UNIT;
-       offset -= TREE_INT_CST_LOW (DECL_FIELD_BIT_OFFSET (field));
+       /* We can be called with a model different from the one associated
+          with BASE so we need to avoid going up the chain too far.  */
+       if (offset - bit_pos < 0)
+         break;
 
+       offset -= bit_pos;
        VEC_safe_push (tree, stack, cr_stack, expr);
 
        expr = TREE_OPERAND (expr, 0);