[gcc r13-10145] ipa/111036 - strip nop conversions around __builtin_constant_p arguments

[Richard Biener]

https://gcc.gnu.org/g:453b952a787d28e9a3081f0b0786cd3ed7ffa7b9

commit r13-10145-g453b952a787d28e9a3081f0b0786cd3ed7ffa7b9
Author: Richard Biener <rguenther@suse.de>
Date:   Wed Jan 28 10:55:56 2026 +0100

    ipa/111036 - strip nop conversions around __builtin_constant_p arguments
    
    The PR is about inconsistent behavior wrt inline predicate analysis
    and later folding of __builtin_constant_p which ultimatively results
    from fold_builtin_constant_p stripping nops off its argument but
    this not being done on GIMPLE.  The following adds a match.pd pattern
    for this.
    
            PR ipa/111036
            * match.pd (__builtin_constant_p ((T)x)): Strip nop-conversions
            from __builtin_constant_p arguments.
    
            * gcc.dg/torture/pr111036.c: New testcase.
    
    (cherry picked from commit 8c0458505a9b1b276fbad81d20849b88eda12d24)

Diff:
---
 gcc/match.pd                            |  5 +++++
 gcc/testsuite/gcc.dg/torture/pr111036.c | 24 ++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/gcc/match.pd b/gcc/match.pd
index bbcc6587569d..b3c755e75bc8 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -8528,3 +8528,8 @@ and,
       }
       (if (full_perm_p)
 	(vec_perm (op@3 @0 @1) @3 @2))))))
+
+/* Strip nop-conversions __builtin_constant_p arguments.  */
+(simplify
+ (BUILT_IN_CONSTANT_P (nop_convert@1 @0))
+ (BUILT_IN_CONSTANT_P @0))
diff --git a/gcc/testsuite/gcc.dg/torture/pr111036.c b/gcc/testsuite/gcc.dg/torture/pr111036.c
new file mode 100644
index 000000000000..f3a0e61705d2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr111036.c
@@ -0,0 +1,24 @@
+/* { dg-do run } */
+
+#include <stdlib.h>
+
+__attribute__((aligned(32))) static struct
+{
+  unsigned long long available_cmd_ids_per_core[2];
+} _rl2c_cmd_id_data;
+
+static inline void __attribute__((always_inline))
+foo (void *base, size_t length)
+{
+  unsigned long int p = (unsigned long int) base;
+  if (__builtin_constant_p(p) && (p & 31) == 0) { exit (0); } 
+  else if (__builtin_constant_p(length)) { exit (0); } 
+  else { exit (0); }
+}
+
+int main(int argc, char **argv)
+{
+  foo(&_rl2c_cmd_id_data, sizeof(*(&_rl2c_cmd_id_data)));
+  return 0;
+}
+