On 8/28/18 12:10 PM, Richard Biener wrote:
> On Tue, Aug 28, 2018 at 9:11 AM Martin Liška <mli...@suse.cz> wrote:
>>
>> On 08/27/2018 05:21 PM, Richard Biener wrote:
>>> On Mon, Aug 27, 2018 at 4:05 PM Martin Liška <mli...@suse.cz> wrote:
>>>>
>>>> Hi.
>>>>
>>>> Now we should not meet a degenerated gswitch statements.
>>>>
>>>> Patch can bootstrap on x86_64-linux-gnu and survives regression tests.
>>>>
>>>> Ready to be installed?
>>>
>>> Hum. This relies on us doing CFG cleanup. Do we really want
>>> find_taken_edge to ICE when called between CFG construction
>>> and the first such call? That is, I think this kind of "verification"
>>> belongs in the CFG verifier. Note that there's GIMPLE switches
>>> before we have a CFG and those are not sanitized (at least
>>> not that I know of). So we cannot really declare single-case
>>> switch stmts invalid?
>>
>> Thanks for explanation. In case of switch_conversion::expand, may I apply
>> patch for that? It should not see a degenerated switch, or do I miss
>> something?
>
> Hopefully not.
I missed as it caused PR87686. Thus I'm reverting that.
Patch is tested on x86_64-linux-gnu.
Martin
>
> So that part is OK.
>
> Richard.
>
>> Martin
>>
>>>
>>> Thanks,
>>> Richard.
>>>
>>>> Martin
>>>>
>>>> gcc/ChangeLog:
>>>>
>>>> 2018-08-27 Martin Liska <mli...@suse.cz>
>>>>
>>>> * tree-cfg.c (find_taken_edge_switch_expr): Replace not possible
>>>> condition with assert.
>>>> * tree-switch-conversion.c (switch_conversion::expand):
>>>> Likewise.
>>>> ---
>>>> gcc/tree-cfg.c | 17 +++++++----------
>>>> gcc/tree-switch-conversion.c | 9 +--------
>>>> 2 files changed, 8 insertions(+), 18 deletions(-)
>>>>
>>>>
>>
>From 1a1f856006be42bb2f94d9df7bad314651fa8e8c Mon Sep 17 00:00:00 2001
From: marxin <mli...@suse.cz>
Date: Mon, 22 Oct 2018 13:13:08 +0200
Subject: [PATCH] Revert r263947.
gcc/ChangeLog:
2018-10-22 Martin Liska <mli...@suse.cz>
Revert
2018-08-29 Martin Liska <mli...@suse.cz>
* tree-switch-conversion.c (switch_conversion::expand):
Strenghten assumption about gswitch statements.
gcc/testsuite/ChangeLog:
2018-10-22 Martin Liska <mli...@suse.cz>
* g++.dg/tree-ssa/pr87686.C: New test.
---
gcc/testsuite/g++.dg/tree-ssa/pr87686.C | 21 +++++++++++++++++++++
gcc/tree-switch-conversion.c | 9 ++++++++-
2 files changed, 29 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/tree-ssa/pr87686.C
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr87686.C b/gcc/testsuite/g++.dg/tree-ssa/pr87686.C
new file mode 100644
index 00000000000..65160a79855
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr87686.C
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+class a {
+public:
+ enum b { c, g, d, e } f;
+ a(b h) : f(h) {}
+ a i() {
+ switch (f) {
+ case d:
+ return c;
+ case e:
+ return g;
+ }
+ } /* { dg-warning "control reaches end of non-void function" } */
+};
+struct k {
+ a j;
+ k l() { j.i(); } /* { dg-warning "no return statement in function returning non-void" } */
+};
+void m(k h) { h.l(); }
diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c
index 64169a6cd3d..ac2aa585257 100644
--- a/gcc/tree-switch-conversion.c
+++ b/gcc/tree-switch-conversion.c
@@ -913,7 +913,14 @@ switch_conversion::expand (gswitch *swtch)
/* Group case labels so that we get the right results from the heuristics
that decide on the code generation approach for this switch. */
m_cfg_altered |= group_case_labels_stmt (swtch);
- gcc_assert (gimple_switch_num_labels (swtch) >= 2);
+
+ /* If this switch is now a degenerate case with only a default label,
+ there is nothing left for us to do. */
+ if (gimple_switch_num_labels (swtch) < 2)
+ {
+ m_reason = "switch is a degenerate case";
+ return;
+ }
collect (swtch);
--
2.19.0
