This splits out the non-constant folding part of an earlier approved patch
to make -ftrapv work better.
The constant folding case is still broken (also ubsan doesn't handle it
correctly).
Bootstrapped and tested on x86_64-unknown-linux-gnu, applied to trunk.
Richard.
2015-10-22 Richard Biener <rguent...@suse.de>
PR middle-end/68046
PR middle-end/61893
* optabs.c (emit_libcall_block_1): Allow a NULL_RTX equiv.
(expand_binop): For -ftrapv optabs do not record an REG_EQUAL note.
(expand_unop): Likewise.
* gcc.dg/torture/ftrapv-2.c: New testcase.
Index: gcc/optabs.c
===================================================================
--- gcc/optabs.c (revision 229166)
+++ gcc/optabs.c (working copy)
@@ -1748,11 +1748,12 @@ expand_binop (machine_mode mode, optab b
insns = get_insns ();
end_sequence ();
+ bool trapv = trapv_binoptab_p (binoptab);
target = gen_reg_rtx (mode);
emit_libcall_block_1 (insns, target, value,
- gen_rtx_fmt_ee (optab_to_code (binoptab),
- mode, op0, op1),
- trapv_binoptab_p (binoptab));
+ trapv ? NULL_RTX
+ : gen_rtx_fmt_ee (optab_to_code (binoptab),
+ mode, op0, op1), trapv);
return target;
}
@@ -2880,13 +2881,19 @@ expand_unop (machine_mode mode, optab un
end_sequence ();
target = gen_reg_rtx (outmode);
- eq_value = gen_rtx_fmt_e (optab_to_code (unoptab), mode, op0);
- if (GET_MODE_SIZE (outmode) < GET_MODE_SIZE (mode))
- eq_value = simplify_gen_unary (TRUNCATE, outmode, eq_value, mode);
- else if (GET_MODE_SIZE (outmode) > GET_MODE_SIZE (mode))
- eq_value = simplify_gen_unary (ZERO_EXTEND, outmode, eq_value, mode);
- emit_libcall_block_1 (insns, target, value, eq_value,
- trapv_unoptab_p (unoptab));
+ bool trapv = trapv_unoptab_p (unoptab);
+ if (trapv)
+ eq_value = NULL_RTX;
+ else
+ {
+ eq_value = gen_rtx_fmt_e (optab_to_code (unoptab), mode, op0);
+ if (GET_MODE_SIZE (outmode) < GET_MODE_SIZE (mode))
+ eq_value = simplify_gen_unary (TRUNCATE, outmode, eq_value, mode);
+ else if (GET_MODE_SIZE (outmode) > GET_MODE_SIZE (mode))
+ eq_value = simplify_gen_unary (ZERO_EXTEND,
+ outmode, eq_value, mode);
+ }
+ emit_libcall_block_1 (insns, target, value, eq_value, trapv);
return target;
}
@@ -3573,7 +3580,8 @@ emit_libcall_block_1 (rtx_insn *insns, r
}
last = emit_move_insn (target, result);
- set_dst_reg_note (last, REG_EQUAL, copy_rtx (equiv), target);
+ if (equiv)
+ set_dst_reg_note (last, REG_EQUAL, copy_rtx (equiv), target);
if (final_dest != target)
emit_move_insn (final_dest, target);
Index: gcc/testsuite/gcc.dg/torture/ftrapv-2.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/ftrapv-2.c (revision 0)
--- gcc/testsuite/gcc.dg/torture/ftrapv-2.c (working copy)
***************
*** 0 ****
--- 1,32 ----
+ /* { dg-do run } */
+ /* With -flto this degenerates to constant folding which doesn't work. */
+ /* { dg-skip-if "" { *-*-* } { "-flto" } { "" } } */
+ /* { dg-additional-options "-ftrapv" } */
+ /* { dg-require-effective-target trapping } */
+ /* { dg-require-fork unused } */
+
+ #include <stdlib.h>
+ #include <unistd.h>
+ #include <sys/types.h>
+ #include <sys/wait.h>
+
+ /* Verify SImode operations properly trap. PR middle-end/68046 */
+
+ int i = 0x7fffffff;
+
+ int main(void)
+ {
+ pid_t child = fork ();
+ int status = 0;
+ if (child == 0)
+ {
+ volatile int x = i + 1 < i;
+ exit (0);
+ }
+ else if (child == -1)
+ return 0;
+ if (wait (&status) == child
+ && status == 0)
+ abort ();
+ return 0;
+ }
