On 02/17/14 02:28, Eric Botcazou wrote:
Although it's probably time to concede defeat in this particular case, I don't
think we should use the NONJUMP_INSN_P big hammer because we want to eliminate
branches if possible. So I'd just add the minimal test to the two existing
conditions so as to prevent the invalid RTL from being created, e.g.
&& (!JUMP_P (i3) || SET_DEST (set[01]) == pc_rtx)
Done. Attached is the final iteration that got installed.
Verified with a cross compiler. Bootstrap on m68k will start at some
point and finish in the next week or so.
jeff
diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index a20cee3..16c499b 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,10 @@
+2014-02-27 Jeff Law <l...@redhat.com>
+
+ PR rtl-optimization/52714
+ * combine.c (try_combine): When splitting an unrecognized PARALLEL
+ into two independent simple sets, if I3 is a jump, ensure the
+ pattern we place into I3 is a (set (pc) ...)
+
2014-02-27 Mikael Pettersson <mi...@it.uu.se>
Jeff Law <l...@redhat.com>
diff --git a/gcc/combine.c b/gcc/combine.c
index 1b598b4..fc473b6 100644
--- a/gcc/combine.c
+++ b/gcc/combine.c
@@ -3712,6 +3712,9 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
*new_direct_jump_p,
#ifdef HAVE_cc0
&& !reg_referenced_p (cc0_rtx, set0)
#endif
+ /* If I3 is a jump, ensure that set0 is a jump so that
+ we do not create invalid RTL. */
+ && (!JUMP_P (i3) || SET_DEST (set0) == pc_rtx)
)
{
newi2pat = set1;
@@ -3726,6 +3729,9 @@ try_combine (rtx i3, rtx i2, rtx i1, rtx i0, int
*new_direct_jump_p,
#ifdef HAVE_cc0
&& !reg_referenced_p (cc0_rtx, set1)
#endif
+ /* If I3 is a jump, ensure that set1 is a jump so that
+ we do not create invalid RTL. */
+ && (!JUMP_P (i3) || SET_DEST (set1) == pc_rtx)
)
{
newi2pat = set0;
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index be4cb12..b95bcfd 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2014-02-27 Jeff Law <l...@redhat.com>
+
+ PR rtl-optimization/52714
+ * gcc.c-torture/compile/pr52714.c: New test.
+
2014-02-27 Mikael Pettersson <mi...@it.uu.se>
Jeff Law <l...@redhat.com>
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr52714.c
b/gcc/testsuite/gcc.c-torture/compile/pr52714.c
new file mode 100644
index 0000000..03d4990
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr52714.c
@@ -0,0 +1,25 @@
+
+int __re_compile_fastmap(unsigned char *p)
+{
+ unsigned char **stack;
+ unsigned size;
+ unsigned avail;
+
+ stack = __builtin_alloca(5 * sizeof(unsigned char*));
+ if (stack == 0)
+ return -2;
+ size = 5;
+ avail = 0;
+
+ for (;;) {
+ switch (*p++) {
+ case 0:
+ if (avail == size)
+ return -2;
+ stack[avail++] = p;
+ }
+ }
+
+ return 0;
+}
+
