https://gcc.gnu.org/g:07a14a490b8f57dfe2a5b853fb4b88e9e124a92b
commit r16-238-g07a14a490b8f57dfe2a5b853fb4b88e9e124a92b
Author: Andrew Pinski <quic_apin...@quicinc.com>
Date: Sat Apr 5 04:47:59 2025 -0700
Add testcase for bogus Warray-bounds warning dealing with
__builtin_unreachable [PR100038]
After EVRP was switched to the ranger (r12-2305-g398572c1544d8b), we are
better handling the case
where __builtin_unreachable comes after a loop. Instead of removing
__builtin_unreachable and having
the loop become an infinite one; it is kept around longer and allows GCC to
unroll the loop 2 times instead
of 3 times. When GCC unrolled the loop 3 times, GCC would produce a bogus
Warray-bounds warning for the 3rd
iteration.
This adds the testcase to make sure we don't regress on this case. It is
originally extracted from LLVM source
code too.
PR tree-optimization/100038
gcc/testsuite/ChangeLog:
* g++.dg/tree-ssa/pr100038.C: New test.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
Diff:
---
gcc/testsuite/g++.dg/tree-ssa/pr100038.C | 17 +++++++++++++++++
1 file changed, 17 insertions(+)
diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr100038.C
b/gcc/testsuite/g++.dg/tree-ssa/pr100038.C
new file mode 100644
index 000000000000..7024c4db2b21
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/pr100038.C
@@ -0,0 +1,17 @@
+// { dg-do compile }
+// { dg-options "-O2 -Wextra -Wall -Warray-bounds" }
+
+struct SparseBitVectorElement {
+ long Bits[2];
+ int find_first() const;
+};
+
+// we should not get an `array subscript 2 is above array bounds of`
+// warning here because we have an unreachable at that point
+
+int SparseBitVectorElement::find_first() const {
+ for (unsigned i = 0; i < 2; ++i)
+ if (Bits[i]) // { dg-bogus "is above array bounds of" }
+ return i;
+ __builtin_unreachable();
+}
