Bootstrapped and tested on x86_64-unknown-linux-gnu, applied.
Richard.
2017-03-27 Richard Biener <rguent...@suse.de>
PR tree-optimization/80181
* tree-ssa-ccp.c (likely_value): UNDEFINED ^ X is UNDEFINED.
* gcc.dg/torture/pr80181.c: New testcase.
Index: gcc/tree-ssa-ccp.c
===================================================================
*** gcc/tree-ssa-ccp.c (revision 246490)
--- gcc/tree-ssa-ccp.c (working copy)
*************** likely_value (gimple *stmt)
*** 741,749 ****
case PLUS_EXPR:
case MINUS_EXPR:
case POINTER_PLUS_EXPR:
/* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected.
Not bitwise operators, one VARYING operand may specify the
! result completely. Not logical operators for the same reason.
Not COMPLEX_EXPR as one VARYING operand makes the result partly
not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because
the undefined operand may be promoted. */
--- 741,751 ----
case PLUS_EXPR:
case MINUS_EXPR:
case POINTER_PLUS_EXPR:
+ case BIT_XOR_EXPR:
/* Not MIN_EXPR, MAX_EXPR. One VARYING operand may be selected.
Not bitwise operators, one VARYING operand may specify the
! result completely.
! Not logical operators for the same reason, apart from XOR.
Not COMPLEX_EXPR as one VARYING operand makes the result partly
not UNDEFINED. Not *DIV_EXPR, comparisons and shifts because
the undefined operand may be promoted. */
Index: gcc/testsuite/gcc.dg/torture/pr80181.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr80181.c (nonexistent)
--- gcc/testsuite/gcc.dg/torture/pr80181.c (working copy)
***************
*** 0 ****
--- 1,19 ----
+ /* { dg-do compile } */
+
+ int
+ nr (void)
+ {
+ }
+
+ void
+ it (int dl)
+ {
+ int vp = 0;
+
+ for (;;)
+ {
+ dl = vp ^ nr ();
+ dl ^= vp;
+ vp = 1;
+ }
+ }
