Hi!
On this testcase on aarch64-linux, we have a bb end like:
(insn 119 80 120 5 (set (reg:DI 110)
(high:DI (label_ref:DI 19))) -1
(insn_list:REG_LABEL_OPERAND 19 (nil)))
(insn 120 119 121 5 (set (reg:DI 109)
(lo_sum:DI (reg:DI 110)
(label_ref:DI 19))) -1
(insn_list:REG_LABEL_OPERAND 19 (expr_list:REG_EQUAL (label_ref:DI 19)
(nil))))
(jump_insn/j 121 120 19 5 (set (pc)
(reg:DI 109)) -1
(nil)
-> 19)
and try to redirect that CROSSING_JUMP_P to another label. As it is not
considered a computed jump (as it has a JUMP_LABEL), but it is hard to
adjust it (we'd need to generate new insns to compute that label into a
register and replace the old ones with it (and find them)), redirect_jump
fails, but patch_jump_insn assumes it must not fail.
I think it is best to allow it to fail, at least until somebody writes code
to redirect_jump even this kind of calls.
Bootstrapped/regtested on x86_64-linux and i686-linux + tested with
aarch64-linux cross on the testcase. Ok for trunk?
2018-11-16 Jakub Jelinek <ja...@redhat.com>
PR rtl-optimization/87475
* cfgrtl.c (patch_jump_insn): Allow redirection failure for
CROSSING_JUMP_P insns.
(cfg_layout_redirect_edge_and_branch): Don't ICE if ret is NULL.
* g++.dg/opt/pr87475.C: New test.
--- gcc/cfgrtl.c.jj 2018-11-15 09:46:46.383739915 +0100
+++ gcc/cfgrtl.c 2018-11-15 16:58:08.972980656 +0100
@@ -1268,11 +1268,13 @@ patch_jump_insn (rtx_insn *insn, rtx_ins
/* If the substitution doesn't succeed, die. This can happen
if the back end emitted unrecognizable instructions or if
- target is exit block on some arches. */
+ target is exit block on some arches. Or for crossing
+ jumps. */
if (!redirect_jump (as_a <rtx_jump_insn *> (insn),
block_label (new_bb), 0))
{
- gcc_assert (new_bb == EXIT_BLOCK_PTR_FOR_FN (cfun));
+ gcc_assert (new_bb == EXIT_BLOCK_PTR_FOR_FN (cfun)
+ || CROSSING_JUMP_P (insn));
return false;
}
}
@@ -4460,6 +4462,9 @@ cfg_layout_redirect_edge_and_branch (edg
else
ret = redirect_branch_edge (e, dest);
+ if (!ret)
+ return NULL;
+
fixup_partition_crossing (ret);
/* We don't want simplejumps in the insn stream during cfglayout. */
gcc_assert (!simplejump_p (BB_END (src)) || CROSSING_JUMP_P (BB_END (src)));
--- gcc/testsuite/g++.dg/opt/pr87475.C.jj 2018-11-15 17:05:51.793393450
+0100
+++ gcc/testsuite/g++.dg/opt/pr87475.C 2018-11-15 17:05:34.713673436 +0100
@@ -0,0 +1,7 @@
+// PR rtl-optimization/87475
+// { dg-do compile { target freorder } }
+// { dg-options "-O2 -freorder-blocks-and-partition -fmodulo-sched" }
+
+struct A { A (); ~A (); };
+int foo (A, A);
+void bar (bool x) { x ? foo (A (), A ()) : 0; }
Jakub
