[gcc r16-1097] Use MEM_EXPR only if MEM_P is true

[H.J. Lu via Gcc-cvs]

https://gcc.gnu.org/g:f7df645956459c559f254d622090d4dd09159890

commit r16-1097-gf7df645956459c559f254d622090d4dd09159890
Author: H.J. Lu <hjl.to...@gmail.com>
Date:   Wed Jun 4 08:48:40 2025 +0800

    Use MEM_EXPR only if MEM_P is true
    
    On s390x, for input:
    
    (call_insn/u 7 6 11 2 (parallel [
                (set (reg:SI 2 %r2)
                    (call (subreg:QI (symbol_ref:SI ("__tls_get_offset") [flags 
0x1]) 3)
                        (const_int 0 [0])))
                (clobber (reg:SI 14 %r14))
                (use (unspec:SI [
                            (const_int 0 [0])
                        ] UNSPEC_TLSLDM))
            ]) "/tmp/foo.c":12:26 2602 {*brasl_tls}
         (expr_list:REG_EH_REGION (const_int -2147483648 [0xffffffff80000000])
            (nil))
        (expr_list (use (reg:SI 2 %r2))
            (expr_list (use (reg:SI 12 %r12))
                (nil))))
    
    after r16-1041-g2da641d0170090, get_call_rtx_from returns:
    
    (call (subreg:QI (symbol_ref:SI ("__tls_get_offset") [flags 0x1]) 3)
        (const_int 0 [0]))
    
    and we got
    
    Program received signal SIGSEGV, Segmentation fault.
    0x000000000131174f in prepare_call_arguments (
        bb=<basic_block 0x7fffe99dfba0 (2)>, insn=0x7fffe980cc60)
        at /export/gnu/import/git/sources/gcc/gcc/var-tracking.cc:6277
    6277            fndecl = MEM_EXPR (XEXP (call, 0));
    (gdb) bt
        bb=<basic_block 0x7fffe99dfba0 (2)>, insn=0x7fffe980cc60)
        at /export/gnu/import/git/sources/gcc/gcc/var-tracking.cc:6277
        at /export/gnu/import/git/sources/gcc/gcc/var-tracking.cc:10297
        at /export/gnu/import/git/sources/gcc/gcc/var-tracking.cc:10526
        at /export/gnu/import/git/sources/gcc/gcc/var-tracking.cc:10579
        at /export/gnu/import/git/sources/gcc/gcc/var-tracking.cc:10616
    
    Update prepare_call_arguments to check MEM_P before using MEM_EXPR.
    
    gcc/
    
            PR debug/120525
            * var-tracking.cc (prepare_call_arguments): Use MEM_EXPR only
            if MEM_P is true.
    
    gcc/testsuite/
    
            PR debug/120525
            * gcc.dg/pr120525.c: New test.
    
    Signed-off-by: H.J. Lu <hjl.to...@gmail.com>

Diff:
---
 gcc/testsuite/gcc.dg/pr120525.c | 22 ++++++++++++++++++++++
 gcc/var-tracking.cc             |  2 +-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/gcc/testsuite/gcc.dg/pr120525.c b/gcc/testsuite/gcc.dg/pr120525.c
new file mode 100644
index 000000000000..5ab7a2244dc2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr120525.c
@@ -0,0 +1,22 @@
+/* { dg-do compile { target fpic } } */
+/* { dg-options "-O2 -fpic -g" } */
+/* { dg-additional-options "-m31" { target s390x-*-* } } */
+
+typedef __SIZE_TYPE__ uintptr_t;
+static __thread uintptr_t start_sp;
+static inline uintptr_t
+__thread_stack_pointer (void)
+{
+  return (uintptr_t) __builtin_frame_address (0);
+}
+
+void
+update_data (void)
+{
+  if (__builtin_expect ((!start_sp), 0))
+    start_sp = __thread_stack_pointer ();
+
+  uintptr_t sp = __thread_stack_pointer ();
+  if (__builtin_expect ((sp > start_sp), 0))
+    start_sp = sp;
+}
diff --git a/gcc/var-tracking.cc b/gcc/var-tracking.cc
index d70ed02e98cd..8732c3ba62aa 100644
--- a/gcc/var-tracking.cc
+++ b/gcc/var-tracking.cc
@@ -6273,7 +6273,7 @@ prepare_call_arguments (basic_block bb, rtx_insn *insn)
          if (SYMBOL_REF_DECL (symbol))
            fndecl = SYMBOL_REF_DECL (symbol);
        }
-      if (fndecl == NULL_TREE)
+      if (fndecl == NULL_TREE && MEM_P (XEXP (call, 0)))
        fndecl = MEM_EXPR (XEXP (call, 0));
       if (fndecl
          && TREE_CODE (TREE_TYPE (fndecl)) != FUNCTION_TYPE