aarch64: Fix folding of degenerate svwhilele case [PR117045]

The svwhilele folder mishandled the degenerate case in which
the second argument is the maximum integer.  In that case,
the result is all-true regardless of the first parameter:

  If the second scalar operand is equal to the maximum signed integer
  value then a condition which includes an equality test can never fail
  and the result will be an all-true predicate.

This is because the conceptual "increment the first operand
by 1 after each element" is done modulo the range of the operand.
The GCC code was instead treating it as infinite precision.
whilele_5.c even had a test for the incorrect behaviour.

The easiest fix seemed to be to handle that case specially before
doing constant folding.  This also copes with variable first operands.

gcc/
	PR target/116999
	PR target/117045
	* config/aarch64/aarch64-sve-builtins-base.cc
	(svwhilelx_impl::fold): Check for WHILELTs of the minimum value
	and WHILELEs of the maximum value.  Fold them to all-false and
	all-true respectively.

gcc/testsuite/
	PR target/116999
	PR target/117045
	* gcc.target/aarch64/sve/acle/general/whilele_5.c: Fix bogus
	expected result.
	* gcc.target/aarch64/sve/acle/general/whilele_11.c: New test.
	* gcc.target/aarch64/sve/acle/general/whilele_12.c: Likewise.

0 files changed, 0 insertions, 0 deletions