Hi,
Could a gatekeeper please help review the following bug?
Bug case:
typedef signed char int8_t;
typedef int int32_t;
typedef long int int64_t;
typedef unsigned long int uint64_t;
struct S0 {
};
struct S1 {
int8_t f2;
};
int32_t g_45 = 4L;
struct S0 * const g_376[9][1] = {
};
struct S0 * const *g_375 = &g_376[7][0];
struct S1 g_611 = { 0U};
void func_75()
{
uint64_t l_79 = 0x024CA9A92ED16080LL;
int32_t *l_80 = &g_45;
lbl_732: (*l_80) &= l_79;
for (g_45 = (-28);
(g_45 <= (-6));
g_45 = safe_add_func_int32_t_s_s(g_45, 1)) {
for (l_79 = 0;
l_79 < 10;
l_79 += 10) {
struct S0 l_731[4] = {
};
(**g_375) = l_731[1];
}
if (l_79) goto lbl_732;
for (g_611.f2 = 5;
g_611.f2 < 6;
g_611.f2 += 1) {
}
}
}
opencc asserts:
### Assertion failure at line 921 of
/fc/proj/ctires/open64/o64guru/src/Sun/trunk/osprey/be/opt/opt_verify.cxx:
### Compiler Error in file bug889-2.c during Global Optimization -- Verify
Live-Range phase:
### sym9v3(cr16) live range overlapped with cur_version sym9v2(cr9) in bb3
line 22
Analysis:
sym9 is the return_vsym and the assertion occurs at the second round DCE
after the CFG optimisation. The Chi/Phis to return_vsym are marked live
only when the return stmt in the exit BB is marked live and then propagated
back to references in other BBs. However, in this case, the return stmt is
deleted by DCE or (unreachable from the first BB). So, remaining stmts with
Chi to return_vsym will get a reference error.
Suggested patch:
Since these are relative rarely-seen cases from auto-generated program and
we'd better don't change the DCE algorithm for other good run cases.
we accept this corner case and it does still preserve the right compiling.
osprey/be/opt/opt_verify.cxx -- 85c7d86..bd8b8ed 100644
--- INDEX:/osprey/be/opt/opt_verify.cxx
+++ WORKDIR:/osprey/be/opt/opt_verify.cxx
@@ -915,6 +917,19 @@ Verify_version_CR(CODEREP *cr, OPT_STAB *opt_stab,
BB_NODE *bb, INT32 linenum)
return;
}
+ // open64.net bug889. The Chi/Phis to return_vsym are marked live only
+ // when the return stmt in the exit BB is marked live and
+ // then propagated back to references in other BBs. However, in the case
of
+ // return stmt is deleted by DCE or (unreachable from the first BB),
+ // remaining stmts with Chi to return_vsym will get a reference error
+ // we allow this corner case since we don't want change the main DCE
algorithm
+ // and allow this still do right compiling.
+
+ if (cr->Aux_id() == opt_stab->Return_vsym() &&
+ !(opt_stab->Cfg()->Exit_bb()->Reached() ||
+ opt_stab->Cfg()->Fake_exit_bb()->Reached()))
+ return;
+
thanks.
Regards
Gang
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