On Tue, Jul 25, 2017 at 03:47:31PM +0200, Richard Biener wrote:
> On Tue, Jul 25, 2017 at 3:30 PM, Eric Botcazou <ebotca...@adacore.com> wrote:
> >> Eric, any comments?
> >
> > No objection for the build2_stat hunk, I think it's in keeping with the Ada
> > semantics. But the tree_could_trap_p hunk is certainly an abomination...
> >
> >> 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.
> >
> > Yes, that would be faster & simpler and avoids the abomination.
>
> Ok, then let's go with that slightly uglier but less abominal variant ;)
Like this then?
Bootstrapped/regtested on x86_64-linux (including Ada) and
powerpc64le-unknown-linux-gnu,
ok for trunk?
2017-07-26 Marek Polacek <pola...@redhat.com>
PR middle-end/70992
* tree.c (build2_stat): Don't set TREE_CONSTANT on divisions by zero.
* 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.c gcc/tree.c
index b7de2840ac6..48fb2ce0651 100644
--- gcc/tree.c
+++ gcc/tree.c
@@ -4456,7 +4456,7 @@ build1_stat (enum tree_code code, tree type, tree node
MEM_STAT_DECL)
tree
build2_stat (enum tree_code code, tree tt, tree arg0, tree arg1 MEM_STAT_DECL)
{
- bool constant, read_only, side_effects;
+ bool constant, read_only, side_effects, div_by_zero;
tree t;
gcc_assert (TREE_CODE_LENGTH (code) == 2);
@@ -4489,6 +4489,23 @@ build2_stat (enum tree_code code, tree tt, tree arg0,
tree arg1 MEM_STAT_DECL)
read_only = 1;
side_effects = TREE_SIDE_EFFECTS (t);
+ switch (code)
+ {
+ case TRUNC_DIV_EXPR:
+ case CEIL_DIV_EXPR:
+ case FLOOR_DIV_EXPR:
+ case ROUND_DIV_EXPR:
+ case EXACT_DIV_EXPR:
+ case CEIL_MOD_EXPR:
+ case FLOOR_MOD_EXPR:
+ case ROUND_MOD_EXPR:
+ case TRUNC_MOD_EXPR:
+ div_by_zero = integer_zerop (arg1);
+ break;
+ default:
+ div_by_zero = false;
+ }
+
PROCESS_ARG (0);
PROCESS_ARG (1);
@@ -4505,7 +4522,8 @@ 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;
+ /* Don't mark X / 0 as constant. */
+ TREE_CONSTANT (t) = constant && !div_by_zero;
TREE_THIS_VOLATILE (t)
= (TREE_CODE_CLASS (code) == tcc_reference
&& arg0 && TREE_THIS_VOLATILE (arg0));
Marek
