This is the trunk variant of the 54515 fix - we shouldn't really
return NULL_TREE from get_base_address apart from for invalid
inputs (and then it's just GIGO). This makes us go half-way to
fix the PR, I'll followup with a patch to look through
WITH_SIZE_EXPR (after thinking about effects on alias analysis).
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2012-09-11 Richard Guenther <rguent...@suse.de>
PR middle-end/54515
* gimple.c (get_base_address): Do not return NULL_TREE apart
from for WITH_SIZE_EXPR.
* gimple-fold.c (canonicalize_constructor_val): Do not call
get_base_address when not necessary.
* g++.dg/tree-ssa/pr54515.C: New testcase.
Index: gcc/gimple.c
===================================================================
--- gcc/gimple.c (revision 191143)
+++ gcc/gimple.c (working copy)
@@ -2878,16 +2878,12 @@ get_base_address (tree t)
&& TREE_CODE (TREE_OPERAND (t, 0)) == ADDR_EXPR)
t = TREE_OPERAND (TREE_OPERAND (t, 0), 0);
- if (TREE_CODE (t) == SSA_NAME
- || DECL_P (t)
- || TREE_CODE (t) == STRING_CST
- || TREE_CODE (t) == CONSTRUCTOR
- || INDIRECT_REF_P (t)
- || TREE_CODE (t) == MEM_REF
- || TREE_CODE (t) == TARGET_MEM_REF)
- return t;
- else
+ /* ??? Either the alias oracle or all callers need to properly deal
+ with WITH_SIZE_EXPRs before we can look through those. */
+ if (TREE_CODE (t) == WITH_SIZE_EXPR)
return NULL_TREE;
+
+ return t;
}
void
Index: gcc/gimple-fold.c
===================================================================
--- gcc/gimple-fold.c (revision 191143)
+++ gcc/gimple-fold.c (working copy)
@@ -154,13 +154,15 @@ canonicalize_constructor_val (tree cval,
}
if (TREE_CODE (cval) == ADDR_EXPR)
{
- tree base = get_base_address (TREE_OPERAND (cval, 0));
- if (!base && TREE_CODE (TREE_OPERAND (cval, 0)) == COMPOUND_LITERAL_EXPR)
+ tree base = NULL_TREE;
+ if (TREE_CODE (TREE_OPERAND (cval, 0)) == COMPOUND_LITERAL_EXPR)
{
base = COMPOUND_LITERAL_EXPR_DECL (TREE_OPERAND (cval, 0));
if (base)
TREE_OPERAND (cval, 0) = base;
}
+ else
+ base = get_base_address (TREE_OPERAND (cval, 0));
if (!base)
return NULL_TREE;
Index: gcc/testsuite/g++.dg/tree-ssa/pr54515.C
===================================================================
--- gcc/testsuite/g++.dg/tree-ssa/pr54515.C (revision 0)
+++ gcc/testsuite/g++.dg/tree-ssa/pr54515.C (working copy)
@@ -0,0 +1,19 @@
+// { dg-do compile }
+// { dg-options "-O2" }
+
+template < typename T > T h2le (T)
+{
+ T a;
+ unsigned short &b = a;
+ short c = 0;
+ unsigned char (&d)[2] = reinterpret_cast < unsigned char (&)[2] > (c);
+ unsigned char (&e)[2] = reinterpret_cast < unsigned char (&)[2] > (b);
+ e[0] = d[0];
+ return a;
+}
+
+void
+bar ()
+{
+ h2le ((unsigned short) 0);
+}
