rs6000: Fix wrong code generation for vec_sel [PR94613]

The vsel instruction is a bit-wise select instruction.  Using an
IF_THEN_ELSE to express it in RTL is wrong and leads to wrong code
being generated in the combine pass.  Per element selection is a
subset of per bit-wise selection,with the patch the pattern is
written using bit operations.  But there are 8 different patterns
to define "op0 := (op1 & ~op3) | (op2 & op3)":

(~op3&op1) | (op3&op2),
(~op3&op1) | (op2&op3),
(op3&op2) | (~op3&op1),
(op2&op3) | (~op3&op1),
(op1&~op3) | (op3&op2),
(op1&~op3) | (op2&op3),
(op3&op2) | (op1&~op3),
(op2&op3) | (op1&~op3),

The latter 4 cases does not follow canonicalisation rules, non-canonical
RTL is invalid RTL in vregs pass.  Secondly, combine pass will swap
(op1&~op3) to (~op3&op1) by commutative canonical, which could reduce
it to the FIRST 4 patterns, but it won't swap (op2&op3) | (~op3&op1) to
(~op3&op1) | (op2&op3), so this patch handles it with 4 patterns with
different NOT op3 position and check equality inside it.

Tested pass on P7, P8 and P9.

gcc/ChangeLog:

2021-10-28  Xionghu Luo  <luoxhu@linux.ibm.com>

	PR target/94613
	* config/rs6000/altivec.md (*altivec_vsel<mode>): Change to ...
	(altivec_vsel<mode>): ... this and update define.
	(*altivec_vsel<mode>_uns): Delete.
	(altivec_vsel<mode>2): New define_insn.
	(altivec_vsel<mode>3): Likewise.
	(altivec_vsel<mode>4): Likewise.
	* config/rs6000/rs6000-call.c (altivec_expand_vec_sel_builtin): New.
	(altivec_expand_builtin): Call altivec_expand_vec_sel_builtin to expand
	vel_sel.
	* config/rs6000/rs6000.c (rs6000_emit_vector_cond_expr): Use bit-wise
	selection instead of per element.
	* config/rs6000/vector.md:
	* config/rs6000/vsx.md (*vsx_xxsel<mode>): Change to ...
	(vsx_xxsel<mode>): ... this and update define.
	(*vsx_xxsel<mode>_uns): Delete.
	(vsx_xxsel<mode>2): New define_insn.
	(vsx_xxsel<mode>3): Likewise.
	(vsx_xxsel<mode>4): Likewise.

gcc/testsuite/ChangeLog:

2021-10-28  Xionghu Luo  <luoxhu@linux.ibm.com>

	PR target/94613
	* gcc.target/powerpc/pr94613.c: New test.

0 files changed, 0 insertions, 0 deletions