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| author | Aldy Hernandez <aldyh@redhat.com> | 2018-01-10 21:39:20 +0000 |
|---|---|---|
| committer | Aldy Hernandez <aldyh@gcc.gnu.org> | 2018-01-10 21:39:20 +0000 |
| commit | e7c6abad7f0bcbf0e60d27bc8cff1087c5195f76 (patch) | |
| tree | 4b719a808b76f3cf629aba03fa7b178fe0ecf8ba /gcc | |
| parent | 266404a8d62b99ab6dd6579bbd33fca32e91ca3b (diff) | |
| download | gcc-e7c6abad7f0bcbf0e60d27bc8cff1087c5195f76.zip gcc-e7c6abad7f0bcbf0e60d27bc8cff1087c5195f76.tar.gz gcc-e7c6abad7f0bcbf0e60d27bc8cff1087c5195f76.tar.bz2 | |
re PR middle-end/81897 (spurious -Wmaybe-uninitialized warning)
PR middle-end/81897
* tree-ssa-uninit.c (convert_control_dep_chain_into_preds): Skip
empty blocks.
From-SVN: r256456
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/uninit-pr81897-2.c | 35 | ||||
| -rw-r--r-- | gcc/tree-ssa-uninit.c | 9 |
3 files changed, 49 insertions, 1 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 413f24c..ba1a844 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2018-01-10 Aldy Hernandez <aldyh@redhat.com> + + PR middle-end/81897 + * tree-ssa-uninit.c (convert_control_dep_chain_into_preds): Skip + empty blocks. + 2018-01-10 Eric Botcazou <ebotcazou@adacore.com> * dwarf2out.c (dwarf2out_var_location): Do not pass NULL to fprintf. diff --git a/gcc/testsuite/gcc.dg/uninit-pr81897-2.c b/gcc/testsuite/gcc.dg/uninit-pr81897-2.c new file mode 100644 index 0000000..3960af4 --- /dev/null +++ b/gcc/testsuite/gcc.dg/uninit-pr81897-2.c @@ -0,0 +1,35 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -fno-tree-ccp -Wmaybe-uninitialized" } */ + +int oo; + +void +pc (int *tt) +{ + int cf = 0; + + if (*tt != 0) + { + if (0) + { + int *qg; + int uj = 0; + + t6: + tt = &cf; + if (oo != 0) + { + ++uj; /* { dg-warning "may be used uninit" } */ + *qg = !!oo && !!uj; /* { dg-warning "may be used uninit" } */ + } + } + cf = 0; + goto t6; + } + + if (oo != 0) + { + *tt = 1; + goto t6; + } +} diff --git a/gcc/tree-ssa-uninit.c b/gcc/tree-ssa-uninit.c index 3823947..8ccbc85 100644 --- a/gcc/tree-ssa-uninit.c +++ b/gcc/tree-ssa-uninit.c @@ -669,9 +669,16 @@ convert_control_dep_chain_into_preds (vec<edge> *dep_chains, e = one_cd_chain[j]; guard_bb = e->src; gsi = gsi_last_bb (guard_bb); - /* Ignore empty BBs as they're basically forwarder blocks. */ + /* Ignore empty forwarder blocks. */ if (empty_block_p (guard_bb) && single_succ_p (guard_bb)) continue; + /* An empty basic block here is likely a PHI, and is not one + of the cases we handle below. */ + if (gsi_end_p (gsi)) + { + has_valid_pred = false; + break; + } cond_stmt = gsi_stmt (gsi); if (is_gimple_call (cond_stmt) && EDGE_COUNT (e->src->succs) >= 2) /* Ignore EH edge. Can add assertion on the other edge's flag. */ |