Re: [PATCH] Don't create out-of-bounds BIT_FIELD_REFs

[Tom de Vries]

On 03-12-13 13:49, Jakub Jelinek wrote:

On Thu, Nov 28, 2013 at 12:23:43AM +0100, Tom de Vries wrote:

Committed to trunk.

Also ok for 4.8 branch? It's a 4.8/4.9 regression.

Ok, but I guess you need to adjust your patch for 4.8 (tree_to_*
and tree_fits_* to host_integerp/tree_low_cst), so please make sure
you test it before commiting.

Jakub,

Richard B. already ok'ed the patch, but with the checking bit left out.

The functions you mention were in that checking bit.

I've tested and committed attached patch.

Thanks,
- Tom

        Jakub

2013-11-27  Tom de Vries  <t...@codesourcery.com>
	    Marc Glisse  <marc.gli...@inria.fr>

	PR middle-end/59037
	* semantics.c (cxx_fold_indirect_ref): Don't create out-of-bounds
	BIT_FIELD_REF.

	* fold-const.c (fold_indirect_ref_1): Don't create out-of-bounds
	BIT_FIELD_REF.
	* gimplify.c (gimple_fold_indirect_ref): Same.

	* c-c++-common/pr59037.c: New testcase.

diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index 571fc7c..e7e2034 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -7543,7 +7543,7 @@ cxx_fold_indirect_ref (location_t loc, tree type, tree op0, bool *empty_base)
 	      unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT;
 	      tree index = bitsize_int (indexi);
 
-	      if (offset/part_widthi <= TYPE_VECTOR_SUBPARTS (op00type))
+	      if (offset / part_widthi < TYPE_VECTOR_SUBPARTS (op00type))
 		return fold_build3_loc (loc,
 					BIT_FIELD_REF, type, op00,
 					part_width, index);
diff --git a/gcc/fold-const.c b/gcc/fold-const.c
index f666429..7433686 100644
--- a/gcc/fold-const.c
+++ b/gcc/fold-const.c
@@ -16595,7 +16595,7 @@ fold_indirect_ref_1 (location_t loc, tree type, tree op0)
 	      unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT;
 	      tree index = bitsize_int (indexi);
 
-	      if (offset/part_widthi <= TYPE_VECTOR_SUBPARTS (op00type))
+	      if (offset / part_widthi < TYPE_VECTOR_SUBPARTS (op00type))
 		return fold_build3_loc (loc,
 					BIT_FIELD_REF, type, op00,
 					part_width, index);
diff --git a/gcc/gimplify.c b/gcc/gimplify.c
index e711928..1f1deb8 100644
--- a/gcc/gimplify.c
+++ b/gcc/gimplify.c
@@ -4369,7 +4369,7 @@ gimple_fold_indirect_ref (tree t)
           unsigned HOST_WIDE_INT indexi = offset * BITS_PER_UNIT;
           tree index = bitsize_int (indexi);
           if (offset / part_widthi
-              <= TYPE_VECTOR_SUBPARTS (TREE_TYPE (addrtype)))
+              < TYPE_VECTOR_SUBPARTS (TREE_TYPE (addrtype)))
             return fold_build3 (BIT_FIELD_REF, type, TREE_OPERAND (addr, 0),
                                 part_width, index);
 	}
diff --git a/gcc/testsuite/c-c++-common/pr59037.c b/gcc/testsuite/c-c++-common/pr59037.c
new file mode 100644
index 0000000..fae13c2
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/pr59037.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O3" } */
+
+typedef int v4si __attribute__ ((vector_size (16)));
+
+int
+main (int argc, char** argv)
+{
+  v4si x = {0,1,2,3};
+  x = (v4si) {(x)[3], (x)[2], (x)[1], (x)[0]};
+  return x[4];
+}