match.pd: Fix up 1 / X for unsigned X optimization [PR104280]

match.pd: Fix up 1 / X for unsigned X optimization [PR104280]

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.

2022-01-29  Jakub Jelinek  <jakub@redhat.com>
	    Andrew Pinski  <apinski@marvell.com>

	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.