Hi!
On Wed, Nov 02, 2016 at 10:46:40AM +0100, Richard Biener wrote:
> Yeah, plus if a followup test would have disambiguated things (the
> dispatch to the tree oracle for example).
After discussing this on IRC that the dse.c and sched-deps.c (call (mem ...) )
changes are probably not safe, I'm proposing following patch which should be
safe to backport to release branches too, the only occurrences of
!DECL_RTL_SET_P where DECL_RTL worked fine in my bootstraps/regtests were
FUNCTION_DECLs, so the patch should only turn ICEs into returning the safe
return value that the expressions might overlap.
If/once this is in, I'm planning to test/submit a patch adding
/* If one decl is known to be a function or label in a function and
the other is some kind of data, they can't overlap. */
if ((TREE_CODE (exprx) == FUNCTION_DECL
|| TREE_CODE (exprx) == LABEL_DECL)
!= (TREE_CODE (expry) == FUNCTION_DECL
|| TREE_CODE (expry) == LABEL_DECL))
return 1;
before that.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2016-11-04 Jakub Jelinek <[email protected]>
PR target/77834
* alias.c (nonoverlapping_memrefs_p): Return 0 if exprx or expry
doesn't have rtl set.
* gcc.dg/pr77834.c: New test.
--- gcc/alias.c.jj 2016-10-21 17:06:27.000000000 +0200
+++ gcc/alias.c 2016-10-31 11:38:29.448031590 +0100
@@ -2755,6 +2755,13 @@ nonoverlapping_memrefs_p (const_rtx x, c
|| TREE_CODE (expry) == CONST_DECL)
return 1;
+ /* If either of the decls doesn't have DECL_RTL set (e.g. marked as
+ living in multiple places), we can't tell anything. Exception
+ are FUNCTION_DECLs for which we can create DECL_RTL on demand. */
+ if ((!DECL_RTL_SET_P (exprx) && TREE_CODE (exprx) != FUNCTION_DECL)
+ || (!DECL_RTL_SET_P (expry) && TREE_CODE (expry) != FUNCTION_DECL))
+ return 0;
+
rtlx = DECL_RTL (exprx);
rtly = DECL_RTL (expry);
--- gcc/testsuite/gcc.dg/pr77834.c.jj 2016-10-31 11:41:46.290521464 +0100
+++ gcc/testsuite/gcc.dg/pr77834.c 2016-10-31 11:41:24.000000000 +0100
@@ -0,0 +1,18 @@
+/* PR target/77834 */
+/* { dg-do compile } */
+/* { dg-options "-O -ftree-pre -Wno-psabi" } */
+/* { dg-additional-options "-mstringop-strategy=libcall" { target i?86-*-*
x86_64-*-* } } */
+
+typedef int V __attribute__ ((vector_size (64)));
+
+V
+foo (V u, V v, int w)
+{
+ do
+ {
+ if (u[0]) v ^= u[w];
+ }
+ while ((V) { 0, u[w] }[1]);
+ u = (V) { v[v[0]], u[u[0]] };
+ return v + u;
+}
Jakub
