EVRP records some ranges from asserts into SSA_NAME_RANGE_INFO
but fails to assert that the condition the range is derived from
is always true after the SSA names definition. The patch implements
the simplest post-dominance check, basic-block equality.
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
2020-11-26 Richard Biener <rguent...@suse.de>
PR tree-optimizataion/97953
* gimple-ssa-evrp-analyze.c
(evrp_range_analyzer::record_ranges_from_incoming_edge): Make
sure the condition post-dominates the SSA definition before
recording into SSA_NAME_RANGE_INFO.
* gcc.dg/pr97953.c: New testcase.
---
gcc/gimple-ssa-evrp-analyze.c | 6 +++++-
gcc/testsuite/gcc.dg/pr97953.c | 24 ++++++++++++++++++++++++
2 files changed, 29 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.dg/pr97953.c
diff --git a/gcc/gimple-ssa-evrp-analyze.c b/gcc/gimple-ssa-evrp-analyze.c
index 485774d3f22..b998e0b6594 100644
--- a/gcc/gimple-ssa-evrp-analyze.c
+++ b/gcc/gimple-ssa-evrp-analyze.c
@@ -218,7 +218,11 @@ evrp_range_analyzer::record_ranges_from_incoming_edge
(basic_block bb)
push_value_range (vrs[i].first, vrs[i].second);
if (is_fallthru
&& m_update_global_ranges
- && all_uses_feed_or_dominated_by_stmt (vrs[i].first, stmt))
+ && all_uses_feed_or_dominated_by_stmt (vrs[i].first, stmt)
+ /* The condition must post-dominate the definition point. */
+ && (SSA_NAME_IS_DEFAULT_DEF (vrs[i].first)
+ || (gimple_bb (SSA_NAME_DEF_STMT (vrs[i].first))
+ == pred_e->src)))
{
set_ssa_range_info (vrs[i].first, vrs[i].second);
maybe_set_nonzero_bits (pred_e, vrs[i].first);
diff --git a/gcc/testsuite/gcc.dg/pr97953.c b/gcc/testsuite/gcc.dg/pr97953.c
new file mode 100644
index 00000000000..6219619d67b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr97953.c
@@ -0,0 +1,24 @@
+/* { dg-do run } */
+/* { dg-options "-O2 -fno-tree-fre" } */
+
+int __attribute__((noipa))
+foo (int flag, int *p)
+{
+ int val = *p;
+ if (flag)
+ {
+ if (val != 1)
+ __builtin_unreachable ();
+ return 0;
+ }
+ int val2 = *p;
+ return val2 == 2;
+}
+
+int main()
+{
+ int i = 2;
+ if (foo (0, &i) != 1)
+ __builtin_abort ();
+ return 0;
+}
--
2.26.2
