[PATCH] Handle const0_operand for *avx2_pcmp<mode>3_1.

[liuhongt]

*<avx512>_eq<mode>3<mask_scalar_merge_name>_1 supports
nonimm_or_0_operand for op1 and op2, pass_combine would fail to lower
avx512 comparision back to avx2 one when op1/op2 is const0_rtx. It's
because the splitter only support nonimmediate_operand.

Failed to match this instruction:
(set (reg/i:V16QI 20 xmm0)
    (vec_merge:V16QI (const_vector:V16QI [
                (const_int -1 [0xffffffffffffffff]) repeated x16
            ])
        (const_vector:V16QI [
                (const_int 0 [0]) repeated x16
            ])
        (unspec:HI [
                (reg:V16QI 105 [ a ])
                (const_vector:V16QI [
                        (const_int 0 [0]) repeated x16
                    ])
                (const_int 0 [0])
            ] UNSPEC_PCMP)))

The patch extend predicates of the splitter to handles that.

Bootstrapped and regtested on x86_64-pc-linux-gnu{-m32,}.
Ready push to trunk.

gcc/ChangeLog:

	PR target/115517
	* config/i386/sse.md (*avx2_pcmp<mode>3_1): Change predicate
	of operands[1] and operands[2] from nonimmdiate_operand to
	nonimm_or_0_operand.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr115517.c: New test.
---
 gcc/config/i386/sse.md                   |  9 ++++--
 gcc/testsuite/gcc.target/i386/pr115517.c | 38 ++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/i386/pr115517.c

diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index 3bf95f0b0e5..1946d3513be 100644
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -17908,8 +17908,8 @@ (define_insn_and_split "*avx2_pcmp<mode>3_1"
 	  (match_operand:VI_128_256 1 "vector_all_ones_operand")
 	  (match_operand:VI_128_256 2 "const0_operand")
 	  (unspec:<avx512fmaskmode>
-	    [(match_operand:VI_128_256 3 "nonimmediate_operand")
-	     (match_operand:VI_128_256 4 "nonimmediate_operand")
+	    [(match_operand:VI_128_256 3 "nonimm_or_0_operand")
+	     (match_operand:VI_128_256 4 "nonimm_or_0_operand")
 	     (match_operand:SI 5 "const_0_to_7_operand")]
 	     UNSPEC_PCMP)))]
   "TARGET_AVX512VL && ix86_pre_reload_split ()
@@ -17928,6 +17928,11 @@ (define_insn_and_split "*avx2_pcmp<mode>3_1"
 {
   if (INTVAL (operands[5]) == 1)
     std::swap (operands[3], operands[4]);
+
+  operands[3] = force_reg (<MODE>mode, operands[3]);
+  if (operands[4] == CONST0_RTX (<MODE>mode))
+    operands[4] = force_reg (<MODE>mode, operands[4]);
+
   enum rtx_code code = INTVAL (operands[5]) ? GT : EQ;
   emit_move_insn (operands[0], gen_rtx_fmt_ee (code, <MODE>mode,
 					       operands[3], operands[4]));
diff --git a/gcc/testsuite/gcc.target/i386/pr115517.c b/gcc/testsuite/gcc.target/i386/pr115517.c
new file mode 100644
index 00000000000..e91d2c23a6b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/pr115517.c
@@ -0,0 +1,38 @@
+/* { dg-do compile } */
+/* { dg-options "-march=x86-64-v4 -O2" } */
+/* { dg-final { scan-assembler-times "vpcmpeq" 4 } } */
+/* { dg-final { scan-assembler-not {(?n)%k[0-9]} } } */
+
+typedef char v16qi __attribute__((vector_size(16)));
+typedef short v8hi __attribute__((vector_size(16)));
+typedef int v4si __attribute__((vector_size(16)));
+typedef long long v2di __attribute__((vector_size(16)));
+
+v16qi
+foo (v16qi a)
+{
+  v16qi b = {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};
+  return a == b;
+}
+
+v8hi
+foo2 (v8hi a)
+{
+  v8hi b = {0, 0, 0, 0, 0, 0, 0, 0};
+  return a == b;
+}
+
+v4si
+foo3 (v4si a)
+{
+  v4si b = {0, 0, 0, 0};
+  return a == b;
+}
+
+v2di
+foo4 (v2di a)
+{
+  v2di b = {0, 0};
+  return a == b;
+}
+
-- 
2.31.1