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author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2020-01-06 01:01:18 +0100 |
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committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2020-11-29 23:06:59 +0100 |
commit | 701ce0cadbd5eb0655ab0c33de5c8a337a498a34 (patch) | |
tree | 5e398f1e90946d6fd85c6dd8dc52587dd897df4a | |
parent | 540c2c4bf47f0c517c042ff689679b2900bb36a5 (diff) | |
download | sparse-701ce0cadbd5eb0655ab0c33de5c8a337a498a34.tar.gz |
memops: kill dead loads before phi-node conversion
During load simplification it may happen that a load is unused
but if this fact is ignored and the usual conversion to a phi-node
is made, then this value may seem to be needed and can't anymore
be simplified away.
Fix this by removing dead loads during load simplification.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
-rw-r--r-- | memops.c | 5 | ||||
-rw-r--r-- | validation/memops/kill-dead-loads00.c | 22 |
2 files changed, 27 insertions, 0 deletions
@@ -111,6 +111,11 @@ static void simplify_loads(struct basic_block *bb) if (insn->is_volatile) continue; + if (!has_users(insn->target)) { + kill_instruction(insn); + continue; + } + RECURSE_PTR_REVERSE(insn, dom) { int dominance; if (!dom->bb) diff --git a/validation/memops/kill-dead-loads00.c b/validation/memops/kill-dead-loads00.c new file mode 100644 index 00000000..df7ec037 --- /dev/null +++ b/validation/memops/kill-dead-loads00.c @@ -0,0 +1,22 @@ +void fun(void); + +void foo(int *p) +{ + for (*p; *p; *p) { +l: + fun(); + } + + if (0) + goto l; +} + +/* + * check-name: kill-dead-loads00 + * check-command: test-linearize -Wno-decl $file + * + * check-output-ignore + * check-output-excludes: phi\\. + * check-output-pattern(1): load\\. + * check-output-end + */ |