Hi! While gimple_call_combined_fn already do call gimple_builtin_call_types_compatible_p and for most of builtins ensures the right types of arguments, for type generic builtins it does not, from POV of that function those functions are rettype (...). Now, while the FE does some number of argument checking for the type generic builtins, as the testcase below shows, it can be gamed.
So, this patch checks the number of arguments for type generic builtins and does nothing if they have unexpected number of arguments. Also for the returns arg verifies it can access the first argument. Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk? 2026-01-10 Jakub Jelinek <[email protected]> PR tree-optimization/123431 * gimple-range-op.cc (gimple_range_op_handler::maybe_builtin_call): Punt if type-generic builtins with a single argument don't have exactly one argument. For returns_arg punt if call doesn't have at least one argument. * gcc.dg/pr123431.c: New test. --- gcc/gimple-range-op.cc.jj 2026-01-02 09:56:10.182336262 +0100 +++ gcc/gimple-range-op.cc 2026-01-09 15:00:01.166808500 +0100 @@ -1410,6 +1410,8 @@ gimple_range_op_handler::maybe_builtin_c switch (func) { case CFN_BUILT_IN_CONSTANT_P: + if (gimple_call_num_args (call) != 1) + return; m_op1 = gimple_call_arg (call, 0); if (irange::supports_p (TREE_TYPE (m_op1))) m_operator = &op_cfn_constant_p; @@ -1420,21 +1422,29 @@ gimple_range_op_handler::maybe_builtin_c break; CASE_FLT_FN (CFN_BUILT_IN_SIGNBIT): + if (gimple_call_num_args (call) != 1) + return; m_op1 = gimple_call_arg (call, 0); m_operator = &op_cfn_signbit; break; CASE_FLT_FN (CFN_BUILT_IN_ISINF): + if (gimple_call_num_args (call) != 1) + return; m_op1 = gimple_call_arg (call, 0); m_operator = &op_cfn_isinf; break; case CFN_BUILT_IN_ISFINITE: + if (gimple_call_num_args (call) != 1) + return; m_op1 = gimple_call_arg (call, 0); m_operator = &op_cfn_isfinite; break; case CFN_BUILT_IN_ISNORMAL: + if (gimple_call_num_args (call) != 1) + return; m_op1 = gimple_call_arg (call, 0); m_operator = &op_cfn_isnormal; break; @@ -1565,7 +1575,9 @@ gimple_range_op_handler::maybe_builtin_c default: { unsigned arg; - if (gimple_call_fnspec (call).returns_arg (&arg) && arg == 0) + if (gimple_call_fnspec (call).returns_arg (&arg) + && arg == 0 + && gimple_call_num_args (call) > 0) { m_op1 = gimple_call_arg (call, 0); m_operator = &op_cfn_pass_through_arg1; --- gcc/testsuite/gcc.dg/pr123431.c.jj 2026-01-09 15:10:58.084406597 +0100 +++ gcc/testsuite/gcc.dg/pr123431.c 2026-01-09 15:10:20.589057380 +0100 @@ -0,0 +1,19 @@ +/* PR tree-optimization/123431 */ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +extern void foo (int); + +extern inline __attribute__((always_inline)) void +bar (int x, ...) +{ + if (__builtin_constant_p (__builtin_va_arg_pack ())) + foo (x); +} + +void +baz (int x) +{ + bar (1, 2); + bar (3, x); +} Jakub
