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| author | Jakub Jelinek <jakub@redhat.com> | 2024-02-05 10:57:39 +0100 |
|---|---|---|
| committer | Jakub Jelinek <jakub@redhat.com> | 2024-02-05 10:57:39 +0100 |
| commit | dede174fbb57bdd3e26f322b6096d53edf0089c4 (patch) | |
| tree | 4049fb91d868d79972e48773ec2da8ed10e5099c | |
| parent | d413df070ba5efadd2fb8b6c6aa6003b8cae617b (diff) | |
| download | gcc-dede174fbb57bdd3e26f322b6096d53edf0089c4.zip gcc-dede174fbb57bdd3e26f322b6096d53edf0089c4.tar.gz gcc-dede174fbb57bdd3e26f322b6096d53edf0089c4.tar.bz2 | |
lower-bitint: Remove single label _BitInt switches [PR113737]
The following testcase ICEs, because group_case_labels_stmt optimizes
switch (a.0_7) <default: <L6> [50.00%], case 0: <L7> [50.00%], case 2: <L7> [50.00%]>
where L7 block starts with __builtin_unreachable (); to
switch (a.0_7) <default: <L6> [50.00%]>
and single label GIMPLE_SWITCH is something the switch expansion refuses to
lower:
if (gimple_switch_num_labels (m_switch) == 1
|| range_check_type (index_type) == NULL_TREE)
return false;
(range_check_type never returns NULL for BITINT_TYPE), but the gimple
lowering pass relies on all large/huge _BitInt switches to be lowered
by that pass.
The following patch just removes those after making the single successor
edge EDGE_FALLTHRU. I've done it even if !optimize just in case in case
we'd end up with single case label from earlier passes.
2024-02-05 Jakub Jelinek <jakub@redhat.com>
PR tree-optimization/113737
* gimple-lower-bitint.cc (gimple_lower_bitint): If GIMPLE_SWITCH
has just a single label, remove it and make single successor edge
EDGE_FALLTHRU.
* gcc.dg/bitint-84.c: New test.
| -rw-r--r-- | gcc/gimple-lower-bitint.cc | 9 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/bitint-84.c | 32 |
2 files changed, 40 insertions, 1 deletions
diff --git a/gcc/gimple-lower-bitint.cc b/gcc/gimple-lower-bitint.cc index a7cc5ce..e92f573 100644 --- a/gcc/gimple-lower-bitint.cc +++ b/gcc/gimple-lower-bitint.cc @@ -5832,7 +5832,14 @@ gimple_lower_bitint (void) if (optimize) group_case_labels_stmt (swtch); - switch_statements.safe_push (swtch); + if (gimple_switch_num_labels (swtch) == 1) + { + single_succ_edge (bb)->flags |= EDGE_FALLTHRU; + gimple_stmt_iterator gsi = gsi_for_stmt (swtch); + gsi_remove (&gsi, true); + } + else + switch_statements.safe_push (swtch); } } diff --git a/gcc/testsuite/gcc.dg/bitint-84.c b/gcc/testsuite/gcc.dg/bitint-84.c new file mode 100644 index 0000000..dffdf16 --- /dev/null +++ b/gcc/testsuite/gcc.dg/bitint-84.c @@ -0,0 +1,32 @@ +/* PR tree-optimization/113737 */ +/* { dg-do compile { target bitint } } */ +/* { dg-options "-O2 -std=c23" } */ + +#if __BITINT_MAXWIDTH__ >= 129 +_BitInt(129) a; +#else +_BitInt(63) a; +#endif + +int b[1], c; + +int +foo (void) +{ + switch (a) + case 0: + case 2: + return 1; + return 0; +} + +void +bar (int i) +{ + for (;; ++i) + { + c = b[i]; + if (!foo ()) + __asm__ (""); + } +} |