- Give error messages for all causes of non sibling call generation
- When giving error messages clear the musttail flag to avoid ICEs
- Error out when tree-tailcall failed to mark a must-tail call
sibcall. In this case it doesn't know the true reason and only gives
a vague message.
PR83324
gcc/ChangeLog:
* calls.cc (maybe_complain_about_tail_call): Clear must tail
flag on error.
(expand_call): Give error messages for all musttail failures.
---
gcc/calls.cc | 32 ++++++++++++++++++++++++++------
1 file changed, 26 insertions(+), 6 deletions(-)
diff --git a/gcc/calls.cc b/gcc/calls.cc
index 21d78f9779fe..883eb9971257 100644
--- a/gcc/calls.cc
+++ b/gcc/calls.cc
@@ -1249,6 +1249,7 @@ maybe_complain_about_tail_call (tree call_expr, const
char *reason)
return;
error_at (EXPR_LOCATION (call_expr), "cannot tail-call: %s", reason);
+ CALL_EXPR_MUST_TAIL_CALL (call_expr) = 0;
}
/* Fill in ARGS_SIZE and ARGS array based on the parameters found in
@@ -2650,7 +2651,13 @@ expand_call (tree exp, rtx target, int ignore)
/* The type of the function being called. */
tree fntype;
bool try_tail_call = CALL_EXPR_TAILCALL (exp);
- bool must_tail_call = CALL_EXPR_MUST_TAIL_CALL (exp);
+ /* tree-tailcall decided not to do tail calls. Error for the musttail case,
+ unfortunately we don't know the reason so it's fairly vague.
+ When tree-tailcall reported an error it already cleared the flag,
+ so this shouldn't really happen unless the
+ the musttail pass gave up walking before finding the call. */
+ if (!try_tail_call)
+ maybe_complain_about_tail_call (exp, "other reasons");
int pass;
/* Register in which non-BLKmode value will be returned,
@@ -3022,10 +3029,21 @@ expand_call (tree exp, rtx target, int ignore)
pushed these optimizations into -O2. Don't try if we're already
expanding a call, as that means we're an argument. Don't try if
there's cleanups, as we know there's code to follow the call. */
- if (currently_expanding_call++ != 0
- || (!flag_optimize_sibling_calls && !CALL_FROM_THUNK_P (exp))
- || args_size.var
- || dbg_cnt (tail_call) == false)
+ if (currently_expanding_call++ != 0)
+ {
+ maybe_complain_about_tail_call (exp, "inside another call");
+ try_tail_call = 0;
+ }
+ if (!flag_optimize_sibling_calls
+ && !CALL_FROM_THUNK_P (exp)
+ && !CALL_EXPR_MUST_TAIL_CALL (exp))
+ try_tail_call = 0;
+ if (args_size.var)
+ {
+ maybe_complain_about_tail_call (exp, "variable size arguments");
+ try_tail_call = 0;
+ }
+ if (dbg_cnt (tail_call) == false)
try_tail_call = 0;
/* Workaround buggy C/C++ wrappers around Fortran routines with
@@ -3046,13 +3064,15 @@ expand_call (tree exp, rtx target, int ignore)
if (MEM_P (*iter))
{
try_tail_call = 0;
+ maybe_complain_about_tail_call (exp,
+ "hidden string length argument passed on
stack");
break;
}
}
/* If the user has marked the function as requiring tail-call
optimization, attempt it. */
- if (must_tail_call)
+ if (CALL_EXPR_MUST_TAIL_CALL (exp))
try_tail_call = 1;
/* Rest of purposes for tail call optimizations to fail. */
--
2.45.2
