On Tue, Jul 25, 2017 at 2:19 PM, Marek Polacek <pola...@redhat.com> wrote:
> On Thu, Jul 20, 2017 at 08:22:59PM +0200, Richard Biener wrote:
>> No, we shouldn't. Maybe trapping ops shouldn't be marked TREE_CONSTANT?
>> (Make sure to test with Ada...)
>
> That works for both testcases, but I can't say I really like the idea of
> modifying build2... but it's where the TREE_CONSTANT comes from.
Yes, I know.
> The tree_could_trap_p bit is because the C++ FE can pass "< x" around, e.g.
> a LT_EXPR with the first operand null.
Eh... :/
> Bootstrapped/regtested on x86_64-linux (Ada included) and
> powerpc64le-unknown-linux-gnu,
> ok for trunk?
Eric, any comments?
We could also avoid tree_could_trap_p by special-casing only
*_DIV_EXPR and *_MOD_EXPR
with integer zero 2nd operand explicitely in build2 given there's no
"constant" value for this. That is,
for FP 1./0. is NaN (a "constant" value) even if the operation might trap.
Thanks,
Richard.
> 2017-07-25 Marek Polacek <pola...@redhat.com>
>
> PR c/70992
> * tree-eh.c (tree_could_trap_p): Check if the first operand is null.
> * tree.c: Include "tree-eh.h".
> (build2_stat): Only set TREE_CONSTANT if the tree couldn't trap.
>
> * gcc.dg/overflow-warn-1.c: Adjust dg-error.
> * gcc.dg/overflow-warn-2.c: Likewise.
> * gcc.dg/overflow-warn-3.c: Likewise.
> * gcc.dg/overflow-warn-4.c: Likewise.
> * gcc.dg/torture/pr70992-2.c: New test.
> * gcc.dg/torture/pr70992.c: New test.
>
> diff --git gcc/testsuite/gcc.dg/overflow-warn-1.c
> gcc/testsuite/gcc.dg/overflow-warn-1.c
> index 8eb322579cf..a5cd5738636 100644
> --- gcc/testsuite/gcc.dg/overflow-warn-1.c
> +++ gcc/testsuite/gcc.dg/overflow-warn-1.c
> @@ -49,7 +49,7 @@ static int sc = INT_MAX + 1; /* { dg-warning "25:integer
> overflow in expression"
> void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in
> expression" } */
> /* { dg-warning "initialization makes pointer from integer without a cast"
> "null" { target *-*-* } .-1 } */
> void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
> -/* { dg-error "initializer element is not computable at load time"
> "constant" { target *-*-* } .-1 } */
> +/* { dg-error "initializer element is not constant" "constant" { target
> *-*-* } .-1 } */
> /* { dg-warning "initialization makes pointer from integer without a cast"
> "null" { target *-*-* } .-2 } */
> void *r = (1 ? 0 : INT_MAX+1);
>
> diff --git gcc/testsuite/gcc.dg/overflow-warn-2.c
> gcc/testsuite/gcc.dg/overflow-warn-2.c
> index f048d6dae2a..05ab104fa4a 100644
> --- gcc/testsuite/gcc.dg/overflow-warn-2.c
> +++ gcc/testsuite/gcc.dg/overflow-warn-2.c
> @@ -49,7 +49,7 @@ static int sc = INT_MAX + 1; /* { dg-warning "integer
> overflow in expression" }
> void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer overflow in
> expression" } */
> /* { dg-warning "initialization makes pointer from integer without a cast"
> "null" { target *-*-* } .-1 } */
> void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
> -/* { dg-error "initializer element is not computable at load time"
> "constant" { target *-*-* } .-1 } */
> +/* { dg-error "initializer element is not constant" "constant" { target
> *-*-* } .-1 } */
> /* { dg-warning "initialization makes pointer from integer without a cast"
> "null" { target *-*-* } .-2 } */
> void *r = (1 ? 0 : INT_MAX+1);
>
> diff --git gcc/testsuite/gcc.dg/overflow-warn-3.c
> gcc/testsuite/gcc.dg/overflow-warn-3.c
> index 664011e401d..fd4a34f67e2 100644
> --- gcc/testsuite/gcc.dg/overflow-warn-3.c
> +++ gcc/testsuite/gcc.dg/overflow-warn-3.c
> @@ -55,7 +55,7 @@ void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer
> overflow in expression" }
> /* { dg-warning "overflow in constant expression" "constant" { target *-*-*
> } .-1 } */
> /* { dg-warning "initialization makes pointer from integer without a cast"
> "null" { target *-*-* } .-2 } */
> void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
> -/* { dg-error "initializer element is not computable at load time"
> "constant" { target *-*-* } .-1 } */
> +/* { dg-error "initializer element is not constant" "constant" { target
> *-*-* } .-1 } */
> /* { dg-warning "initialization makes pointer from integer without a cast"
> "null" { target *-*-* } .-2 } */
> void *r = (1 ? 0 : INT_MAX+1);
>
> diff --git gcc/testsuite/gcc.dg/overflow-warn-4.c
> gcc/testsuite/gcc.dg/overflow-warn-4.c
> index 52677ce897a..018e3e1e4cd 100644
> --- gcc/testsuite/gcc.dg/overflow-warn-4.c
> +++ gcc/testsuite/gcc.dg/overflow-warn-4.c
> @@ -55,7 +55,7 @@ void *p = 0 * (INT_MAX + 1); /* { dg-warning "integer
> overflow in expression" }
> /* { dg-error "overflow in constant expression" "constant" { target *-*-* }
> .-1 } */
> /* { dg-error "initialization makes pointer from integer without a cast"
> "null" { target *-*-* } .-2 } */
> void *q = 0 * (1 / 0); /* { dg-warning "division by zero" } */
> -/* { dg-error "initializer element is not computable at load time"
> "constant" { target *-*-* } .-1 } */
> +/* { dg-error "initializer element is not constant" "constant" { target
> *-*-* } .-1 } */
> /* { dg-error "initialization makes pointer from integer without a cast"
> "null" { target *-*-* } .-2 } */
> void *r = (1 ? 0 : INT_MAX+1);
>
> diff --git gcc/testsuite/gcc.dg/torture/pr70992-2.c
> gcc/testsuite/gcc.dg/torture/pr70992-2.c
> index e69de29bb2d..c5d2c5f2683 100644
> --- gcc/testsuite/gcc.dg/torture/pr70992-2.c
> +++ gcc/testsuite/gcc.dg/torture/pr70992-2.c
> @@ -0,0 +1,9 @@
> +/* PR middle-end/70992 */
> +/* { dg-do compile } */
> +
> +unsigned int *od;
> +int
> +fn (void)
> +{
> + return (0 % 0 + 1) * *od * 2; /* { dg-warning "division by zero" } */
> +}
> diff --git gcc/testsuite/gcc.dg/torture/pr70992.c
> gcc/testsuite/gcc.dg/torture/pr70992.c
> index e69de29bb2d..56728e09d1b 100644
> --- gcc/testsuite/gcc.dg/torture/pr70992.c
> +++ gcc/testsuite/gcc.dg/torture/pr70992.c
> @@ -0,0 +1,41 @@
> +/* PR middle-end/70992 */
> +/* { dg-do compile } */
> +
> +typedef unsigned int uint32_t;
> +typedef int int32_t;
> +
> +uint32_t
> +fn (uint32_t so)
> +{
> + return (so + so) * (0x80000000 / 0 + 1); /* { dg-warning "division by
> zero" } */
> +}
> +
> +uint32_t
> +fn5 (uint32_t so)
> +{
> + return (0x80000000 / 0 + 1) * (so + so); /* { dg-warning "division by
> zero" } */
> +}
> +
> +uint32_t
> +fn6 (uint32_t so)
> +{
> + return (0x80000000 / 0 - 1) * (so + so); /* { dg-warning "division by
> zero" } */
> +}
> +
> +uint32_t
> +fn2 (uint32_t so)
> +{
> + return (so + so) * (0x80000000 / 0 - 1); /* { dg-warning "division by
> zero" } */
> +}
> +
> +int32_t
> +fn3 (int32_t so)
> +{
> + return (so + so) * (0x80000000 / 0 + 1); /* { dg-warning "division by
> zero" } */
> +}
> +
> +int32_t
> +fn4 (int32_t so)
> +{
> + return (so + so) * (0x80000000 / 0 - 1); /* { dg-warning "division by
> zero" } */
> +}
> diff --git gcc/tree-eh.c gcc/tree-eh.c
> index c68d71a5e54..cde4ef3f387 100644
> --- gcc/tree-eh.c
> +++ gcc/tree-eh.c
> @@ -2599,7 +2599,7 @@ tree_could_trap_p (tree expr)
>
> if (t)
> {
> - if (COMPARISON_CLASS_P (expr))
> + if (COMPARISON_CLASS_P (expr) && TREE_OPERAND (expr, 0))
> fp_operation = FLOAT_TYPE_P (TREE_TYPE (TREE_OPERAND (expr, 0)));
> else
> fp_operation = FLOAT_TYPE_P (t);
> diff --git gcc/tree.c gcc/tree.c
> index b7de2840ac6..205ba7fd79d 100644
> --- gcc/tree.c
> +++ gcc/tree.c
> @@ -62,6 +62,7 @@ along with GCC; see the file COPYING3. If not see
> #include "print-tree.h"
> #include "ipa-utils.h"
> #include "selftest.h"
> +#include "tree-eh.h"
>
> /* Tree code classes. */
>
> @@ -4505,7 +4506,7 @@ build2_stat (enum tree_code code, tree tt, tree arg0,
> tree arg1 MEM_STAT_DECL)
> else
> {
> TREE_READONLY (t) = read_only;
> - TREE_CONSTANT (t) = constant;
> + TREE_CONSTANT (t) = constant && !tree_could_trap_p (t);
> TREE_THIS_VOLATILE (t)
> = (TREE_CODE_CLASS (code) == tcc_reference
> && arg0 && TREE_THIS_VOLATILE (arg0));
>
> Marek
