Hi,
this patch fixes PR65802.
The problem described in PR65802 is that when compiling the test-case (included
in the patch below) at -O0, the compiler runs into a gcc_assert ICE in
redirect_eh_edge_1 during pass_cleanup_eh:
...
gcc_assert (lookup_stmt_eh_lp (throw_stmt) == old_lp_nr);
...
In more detail, during compilation the ifn_va_arg is marked at as a throwing
function. That causes exception handling code to be generated, with exception
handling edges:
...
;; basic block 2, loop depth 0, count 0, freq 0, maybe hot
;; prev block 0, next block 3, flags: (NEW, REACHABLE)
;; pred: ENTRY (FALLTHRU)
[LP 1] # .MEM_5 = VDEF <.MEM_4(D)>
# USE = anything
# CLB = anything
_6 = VA_ARG (&cD.2333, 0B);
;; succ: 7 (EH)
;; 3 (FALLTHRU)
...
After pass_lower_vaarg, the expansion of ifn_va_arg is spread over several basic
blocks:
...
;; basic block 2, loop depth 0, count 0, freq 0, maybe hot
;; prev block 0, next block 11, flags: (NEW, REACHABLE)
;; pred: ENTRY (FALLTHRU)
;; succ: 11 [100.0%] (FALLTHRU)
;; basic block 11, loop depth 0, count 0, freq 0, maybe hot
;; prev block 2, next block 12, flags: (NEW)
;; pred: 2 [100.0%] (FALLTHRU)
# VUSE <.MEM_4(D)>
_22 = cD.2333.gp_offsetD.5;
if (_22 >= 48)
goto <bb 13> (<L6>);
else
goto <bb 12> (<L5>);
;; succ: 13 (TRUE_VALUE)
;; 12 (FALSE_VALUE)
;; basic block 12, loop depth 0, count 0, freq 0, maybe hot
;; prev block 11, next block 13, flags: (NEW)
;; pred: 11 (FALSE_VALUE)
<L5>:
# VUSE <.MEM_4(D)>
_23 = cD.2333.reg_save_areaD.8;
# VUSE <.MEM_4(D)>
_24 = cD.2333.gp_offsetD.5;
_25 = (sizetype) _24;
addr.1_26 = _23 + _25;
# VUSE <.MEM_4(D)>
_27 = cD.2333.gp_offsetD.5;
_28 = _27 + 8;
# .MEM_29 = VDEF <.MEM_4(D)>
cD.2333.gp_offsetD.5 = _28;
goto <bb 14> (<L7>);
;; succ: 14 (FALLTHRU)
;; basic block 13, loop depth 0, count 0, freq 0, maybe hot
;; prev block 12, next block 14, flags: (NEW)
;; pred: 11 (TRUE_VALUE)
<L6>:
# VUSE <.MEM_4(D)>
_30 = cD.2333.overflow_arg_areaD.7;
addr.1_31 = _30;
_32 = _30 + 8;
# .MEM_33 = VDEF <.MEM_4(D)>
cD.2333.overflow_arg_areaD.7 = _32;
;; succ: 14 (FALLTHRU)
;; basic block 14, loop depth 0, count 0, freq 0, maybe hot
;; prev block 13, next block 15, flags: (NEW)
;; pred: 12 (FALLTHRU)
;; 13 (FALLTHRU)
# .MEM_20 = PHI <.MEM_29(12), .MEM_33(13)>
# addr.1_21 = PHI <addr.1_26(12), addr.1_31(13)>
<L7>:
# VUSE <.MEM_20>
_6 = MEM[(intD.9 * * {ref-all})addr.1_21];
;; succ: 15 (FALLTHRU)
;; basic block 15, loop depth 0, count 0, freq 0, maybe hot
;; prev block 14, next block 3, flags: (NEW)
;; pred: 14 (FALLTHRU)
;; succ: 7 (EH)
;; 3 (FALLTHRU)
...
And an ICE is triggered in redirect_eh_edge_1, because the code expects the last
statement in a BB with an outgoing EH edge to be a throwing statement.
That's obviously not the case, since bb15 is empty. But also all the other
statements in the expansion are non-throwing.
Looking at the representation before the ifn_va_arg, VA_ARG_EXPR is non-throwing
(even with -fnon-call-exceptions).
And looking at the situation before the introduction of ifn_va_arg, the
expansion of VA_ARG_EXPR also didn't contain any throwing statements.
This patch fixes the ICE by marking ifn_va_arg with ECF_NOTHROW.
Bootstrapped and reg-tested on x86_64.
OK for trunk?
Thanks,
- Tom
Mark ifn_va_arg with ECF_NOTHROW
2015-04-20 Tom de Vries <t...@codesourcery.com>
PR tree-optimization/65802
* internal-fn.def (VA_ARG): Add ECF_NOTROW to flags.
* g++.dg/pr65802.C: New test.
---
gcc/internal-fn.def | 2 +-
gcc/testsuite/g++.dg/pr65802.C | 29 +++++++++++++++++++++++++++++
2 files changed, 30 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/g++.dg/pr65802.C
diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index f557c64..7e19313 100644
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -62,4 +62,4 @@ DEF_INTERNAL_FN (ADD_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
DEF_INTERNAL_FN (SUB_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
DEF_INTERNAL_FN (MUL_OVERFLOW, ECF_CONST | ECF_LEAF | ECF_NOTHROW, NULL)
DEF_INTERNAL_FN (TSAN_FUNC_EXIT, ECF_NOVOPS | ECF_LEAF | ECF_NOTHROW, NULL)
-DEF_INTERNAL_FN (VA_ARG, 0, NULL)
+DEF_INTERNAL_FN (VA_ARG, ECF_NOTHROW, NULL)
diff --git a/gcc/testsuite/g++.dg/pr65802.C b/gcc/testsuite/g++.dg/pr65802.C
new file mode 100644
index 0000000..26e5317
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr65802.C
@@ -0,0 +1,29 @@
+// { dg-do compile }
+// { dg-options "-O0" }
+
+typedef int tf ();
+
+struct S
+{
+ tf m_fn1;
+} a;
+
+void
+fn1 ()
+{
+ try
+ {
+ __builtin_va_list c;
+ {
+ int *d = __builtin_va_arg (c, int *);
+ int **e = &d;
+ __asm__("" : "=d"(e));
+ a.m_fn1 ();
+ }
+ a.m_fn1 ();
+ }
+ catch (...)
+ {
+
+ }
+}
--
1.9.1
