commit f1555d4013ed3cae2589270436387063d1c2f1a3
author Aldy Hernandez <aldyh@redhat.com> Thu May 13 13:47:41 2021 -0400
committer Aldy Hernandez <aldyh@redhat.com> Thu Jun 17 12:10:41 2021 +0200
tree ce352c9735b2095b6952b2b84a660240dd8be3b8
parent 8eac92a07e386301f7b09f7ef6146e6e3ac6b6cd

Cleanup clz and ctz code in range_of_builtin_call.

These are various cleanups to the clz/ctz code.

First, ranges from range_of_expr are always numeric so we
should adjust.  Also, the checks for non-zero were assuming the argument
was unsigned, which in the PR's testcase is clearly not.  I've cleaned
this up, so that it works either way.

I've also removed the following annoying idiom:

-         int newmini = prec - 1 - wi::floor_log2 (r.upper_bound ());
-         if (newmini == prec)

This is really a check for r.upper_bound() == 0, as floor_log2(0)
returns -1.  It's confusing.

Tested on x86-64 Linux.

gcc/ChangeLog:

	PR tree-optimization/100790
	* gimple-range.cc (range_of_builtin_call): Cleanup clz and ctz
	code.

gcc/testsuite/ChangeLog:

	* gcc.dg/pr100790.c: New test.