Hi!
On Fri, Jan 28, 2022 at 11:38:23AM -0700, Jeff Law wrote:
> Thanks. Given the original submission and most of the review work was done
> prior to stage3 closing, I went ahead and installed this on the trunk.
Unfortunately this breaks quite a lot of things.
The main problem is that GIMPLE allows EQ_EXPR etc. only with BOOLEAN_TYPE
or with TYPE_PRECISION == 1 integral type (or vector boolean).
Violating this causes verification failures in tree-cfg.cc in some cases,
in other cases wrong-code issues because before it is verified we e.g.
transform
1U / x
into
x == 1U
and later into
x (because we assume that == type must be one of the above cases and
when it is the same type as the type of the first operand, for boolean-ish
cases it should be equivalent).
Fixed by changing that
(eq @1 { build_one_cst (type); })
into
(convert (eq:boolean_type_node @1 { build_one_cst (type); }))
Note, I'm not 100% sure if :boolean_type_node is required in that case,
I see some spots in match.pd that look exactly like this, while there is
e.g. (convert (le ...)) that supposedly does the right thing too.
The signed integer 1/X case doesn't need changes changes, for
(cond (le ...) ...)
le gets correctly boolean_type_node and cond should use type.
I've also reformatted it, some lines were too long, match.pd uses
indentation by 1 column instead of 2 etc.
Bootstrapped/regtested on powerpc64le-linux and tested on the testcases
on x86_64-linux, ok for trunk?
2022-01-29 Jakub Jelinek <[email protected]>
Andrew Pinski <[email protected]>
PR tree-optimization/104279
PR tree-optimization/104280
PR tree-optimization/104281
* match.pd (1 / X -> X == 1 for unsigned X): Build eq with
boolean_type_node and convert to type. Formatting fixes.
* gcc.dg/torture/pr104279.c: New test.
* gcc.dg/torture/pr104280.c: New test.
* gcc.dg/torture/pr104281.c: New test.
--- gcc/match.pd.jj 2022-01-29 11:11:39.316628007 +0100
+++ gcc/match.pd 2022-01-29 12:19:46.662096678 +0100
@@ -435,18 +435,22 @@ (define_operator_list SYNC_FETCH_AND_AND
&& TYPE_UNSIGNED (type))
(trunc_divmod @0 @1))))
- /* 1 / X -> X == 1 for unsigned integer X.
- 1 / X -> X >= -1 && X <= 1 ? X : 0 for signed integer X.
- But not for 1 / 0 so that we can get proper warnings and errors,
- and not for 1-bit integers as they are edge cases better handled
elsewhere. */
+/* 1 / X -> X == 1 for unsigned integer X.
+ 1 / X -> X >= -1 && X <= 1 ? X : 0 for signed integer X.
+ But not for 1 / 0 so that we can get proper warnings and errors,
+ and not for 1-bit integers as they are edge cases better handled
+ elsewhere. */
(simplify
- (trunc_div integer_onep@0 @1)
- (if (INTEGRAL_TYPE_P (type) && !integer_zerop (@1) && TYPE_PRECISION (type)
> 1)
- (if (TYPE_UNSIGNED (type))
- (eq @1 { build_one_cst (type); })
- (with { tree utype = unsigned_type_for (type); }
- (cond (le (plus (convert:utype @1) { build_one_cst (utype); }) {
build_int_cst (utype, 2); })
- @1 { build_zero_cst (type); })))))
+ (trunc_div integer_onep@0 @1)
+ (if (INTEGRAL_TYPE_P (type)
+ && !integer_zerop (@1)
+ && TYPE_PRECISION (type) > 1)
+ (if (TYPE_UNSIGNED (type))
+ (convert (eq:boolean_type_node @1 { build_one_cst (type); }))
+ (with { tree utype = unsigned_type_for (type); }
+ (cond (le (plus (convert:utype @1) { build_one_cst (utype); })
+ { build_int_cst (utype, 2); })
+ @1 { build_zero_cst (type); })))))
/* Combine two successive divisions. Note that combining ceil_div
and floor_div is trickier and combining round_div even more so. */
--- gcc/testsuite/gcc.dg/torture/pr104279.c.jj 2022-01-29 12:25:36.388174312
+0100
+++ gcc/testsuite/gcc.dg/torture/pr104279.c 2022-01-29 12:25:53.206937588
+0100
@@ -0,0 +1,12 @@
+/* PR tree-optimization/104279 */
+/* { dg-do compile } */
+
+unsigned a, b;
+
+int
+main ()
+{
+ b = ~(0 || ~0);
+ a = ~b / ~a;
+ return 0;
+}
--- gcc/testsuite/gcc.dg/torture/pr104280.c.jj 2022-01-29 12:24:36.190021595
+0100
+++ gcc/testsuite/gcc.dg/torture/pr104280.c 2022-01-29 12:25:28.681282783
+0100
@@ -0,0 +1,16 @@
+/* PR tree-optimization/104280 */
+/* { dg-do run } */
+
+int
+foo (unsigned b, int c)
+{
+ return b / c;
+}
+
+int
+main ()
+{
+ if (foo (1, 2) != 0)
+ __builtin_abort ();
+ return 0;
+}
--- gcc/testsuite/gcc.dg/torture/pr104281.c.jj 2022-01-29 12:27:29.840577473
+0100
+++ gcc/testsuite/gcc.dg/torture/pr104281.c 2022-01-29 12:27:24.526652267
+0100
@@ -0,0 +1,22 @@
+/* PR tree-optimization/104281 */
+/* { dg-do run } */
+
+unsigned a = 1;
+int b, c = 2;
+long d;
+
+int
+main ()
+{
+ while (1)
+ {
+ int m = a;
+ L:
+ a = ~(-(m || b & d));
+ b = ((1 ^ a) / c);
+ if (b)
+ goto L;
+ break;
+ }
+ return 0;
+}
Jakub
