My sincere apologies to everyone (again). As diagnosed by
Jakub Jelinek, my recent patch to fold the signedness of LSHIFT_EXPR
needs to be careful not to attempt transforming a left shift in an
integer type into an invalid left shift of a pointer type.
This patch has been committed as obvious, after testing that a
"make bootstrap" on x86_64-pc-linux-gnu is unaffected [make -k check
is underway].
Sorry (yet) again.
2021-08-23 Roger Sayle <ro...@nextmovesoftware.com>
Jakub Jelinek <ja...@redhat.com>
gcc/ChangeLog
PR middle-end/102029
* match.pd (shift transformations): Add an additional check for
!POINTER_TYPE_P in the recently added left shift transformation.
gcc/testsuite/ChangeLog
PR middle-end/102029
* gcc.dg/fold-convlshift-3.c: New test case.
Roger
--
diff --git a/gcc/match.pd b/gcc/match.pd
index 978a1b0..e5bbb12 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3389,7 +3389,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
the form that minimizes the number of conversions. */
(simplify
(convert (lshift:s@0 (convert:s@1 @2) INTEGER_CST@3))
- (if (tree_nop_conversion_p (type, TREE_TYPE (@0))
+ (if (INTEGRAL_TYPE_P (type)
+ && !POINTER_TYPE_P (type)
+ && tree_nop_conversion_p (type, TREE_TYPE (@0))
&& INTEGRAL_TYPE_P (TREE_TYPE (@2))
&& TYPE_PRECISION (TREE_TYPE (@2)) <= TYPE_PRECISION (type))
(lshift (convert @2) @3)))
/* PR middle-end/102029 */
/* { dg-do compile } */
/* { dg-options "-O2" } */
int *
foo (const __PTRDIFF_TYPE__ l)
{
return (int *) (l << 2);
}
