[gcc r15-6546] testsuite: torture: add LLVM testcase for DSE vs. -ftrivial-auto-var-init=

[Sam James via Gcc-cvs]

https://gcc.gnu.org/g:26ca00eeedb01f9d5102586b76ae2a6e787111af

commit r15-6546-g26ca00eeedb01f9d5102586b76ae2a6e787111af
Author: Sam James <s...@gentoo.org>
Date:   Fri Dec 13 04:42:29 2024 +0000

    testsuite: torture: add LLVM testcase for DSE vs. -ftrivial-auto-var-init=
    
    This testcase came up in a recent LLVM bug report [0] for DSE vs
    -ftrivial-auto-var-init=. Add it to our testsuite given that area
    could do with better coverage.
    
    [0] https://github.com/llvm/llvm-project/issues/119646
    
    gcc/testsuite/ChangeLog:
    
            * gcc.dg/torture/dse-trivial-auto-var-init.c: New test.
    
    Co-authored-by: Andrew Pinski <pins...@gmail.com>

Diff:
---
 .../gcc.dg/torture/dse-trivial-auto-var-init.c          | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/gcc/testsuite/gcc.dg/torture/dse-trivial-auto-var-init.c 
b/gcc/testsuite/gcc.dg/torture/dse-trivial-auto-var-init.c
new file mode 100644
index 000000000000..5a3d4c4e3ecb
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/dse-trivial-auto-var-init.c
@@ -0,0 +1,17 @@
+/* Testcase for LLVM bug: https://github.com/llvm/llvm-project/issues/119646 */
+/* { dg-do run } */
+/* { dg-additional-options "-ftrivial-auto-var-init=zero" } */
+
+int b = 208;
+[[gnu::noinline]]
+void f(int *e, int a) {
+  *e = !!b;
+  if (a)
+    __builtin_trap();
+}
+int main(void) {
+  b = 0;
+  f(&b, 0);
+  if (b != 0)
+    __builtin_trap();
+}