On Fri, Feb 12, 2016 at 03:20:07PM +0100, Bernd Schmidt wrote:
> >>- mode1 = GET_MODE (xop1) != VOIDmode ? GET_MODE (xop1) : mode;
> >>+ mode1 = GET_MODE (xop1) != VOIDmode ? GET_MODE (xop1) : mode1;
> >> if (xmode1 != VOIDmode && xmode1 != mode1)
> >> {
>
> Here, things aren't so clear, and the fact that the mode1 calculation now
> differs from the mode0 one may be overlooked by someone in the future.
>
> Rather than use codes like "mode variable is VOIDmode", I'd prefer to use
> booleans with descriptive names, like "op1_may_need_conversion".
So do you prefer e.g. following? Bootstrapped/regtested on x86_64-linux and
i686-linux.
2016-02-12 Jakub Jelinek <ja...@redhat.com>
PR rtl-optimization/69764
PR rtl-optimization/69771
* optabs.c (expand_binop_directly): For shift_optab_p, force
convert_modes with VOIDmode if xop1 has VOIDmode.
* c-c++-common/pr69764.c: New test.
* gcc.dg/torture/pr69771.c: New testcase.
--- gcc/optabs.c.jj 2016-02-12 00:50:30.410240366 +0100
+++ gcc/optabs.c 2016-02-12 10:33:32.743492532 +0100
@@ -993,6 +993,7 @@ expand_binop_directly (machine_mode mode
bool commutative_p;
rtx_insn *pat;
rtx xop0 = op0, xop1 = op1;
+ bool canonicalize_op1 = false;
/* If it is a commutative operator and the modes would match
if we would swap the operands, we can save the conversions. */
@@ -1006,6 +1007,11 @@ expand_binop_directly (machine_mode mode
xop0 = avoid_expensive_constant (xmode0, binoptab, 0, xop0, unsignedp);
if (!shift_optab_p (binoptab))
xop1 = avoid_expensive_constant (xmode1, binoptab, 1, xop1, unsignedp);
+ else
+ /* Shifts and rotates often use a different mode for op1 from op0;
+ for VOIDmode constants we don't know the mode, so force it
+ to be canonicalized using convert_modes. */
+ canonicalize_op1 = true;
/* In case the insn wants input operands in modes different from
those of the actual operands, convert the operands. It would
@@ -1020,7 +1026,8 @@ expand_binop_directly (machine_mode mode
mode0 = xmode0;
}
- mode1 = GET_MODE (xop1) != VOIDmode ? GET_MODE (xop1) : mode;
+ mode1 = (GET_MODE (xop1) != VOIDmode || canonicalize_op1)
+ ? GET_MODE (xop1) : mode;
if (xmode1 != VOIDmode && xmode1 != mode1)
{
xop1 = convert_modes (xmode1, mode1, xop1, unsignedp);
--- gcc/testsuite/c-c++-common/pr69764.c.jj 2016-02-12 10:27:34.522587995
+0100
+++ gcc/testsuite/c-c++-common/pr69764.c 2016-02-12 10:27:34.522587995
+0100
@@ -0,0 +1,38 @@
+/* PR rtl-optimization/69764 */
+/* { dg-do compile { target int32plus } } */
+
+unsigned char
+fn1 (unsigned char a)
+{
+ return a >> ~6; /* { dg-warning "right shift count is negative" } */
+}
+
+unsigned short
+fn2 (unsigned short a)
+{
+ return a >> ~6; /* { dg-warning "right shift count is negative" } */
+}
+
+unsigned int
+fn3 (unsigned int a)
+{
+ return a >> ~6; /* { dg-warning "right shift count is negative" } */
+}
+
+unsigned char
+fn4 (unsigned char a)
+{
+ return a >> 0xff03; /* { dg-warning "right shift count >= width of type" }
*/
+}
+
+unsigned short
+fn5 (unsigned short a)
+{
+ return a >> 0xff03; /* { dg-warning "right shift count >= width of type" }
*/
+}
+
+unsigned int
+fn6 (unsigned int a)
+{
+ return a >> 0xff03; /* { dg-warning "right shift count >= width of type" }
*/
+}
--- gcc/testsuite/gcc.dg/torture/pr69771.c.jj 2016-02-12 10:27:34.522587995
+0100
+++ gcc/testsuite/gcc.dg/torture/pr69771.c 2016-02-12 10:27:34.522587995
+0100
@@ -0,0 +1,12 @@
+/* PR rtl-optimization/69771 */
+/* { dg-do compile } */
+
+unsigned char a = 5, c;
+unsigned short b = 0;
+unsigned d = 0x76543210;
+
+void
+foo (void)
+{
+ c = d >> ~(a || ~b); /* { dg-warning "shift count is negative" } */
+}
Jakub
