Improved V1TI (and V2DI) mode equality/inequality on x86_64.

This patch improves support for vector equality and inequality of
V1TImode vectors, and V2DImode vectors with sse2 but not sse4.
Consider the three functions below:

typedef unsigned int uv4si __attribute__ ((__vector_size__ (16)));
typedef unsigned long long uv2di __attribute__ ((__vector_size__ (16)));
typedef unsigned __int128 uv1ti __attribute__ ((__vector_size__ (16)));

uv4si eq_v4si(uv4si x, uv4si y) { return x == y; }
uv2di eq_v2di(uv2di x, uv2di y) { return x == y; }
uv1ti eq_v1ti(uv1ti x, uv1ti y) { return x == y; }

These all perform vector comparisons of 128bit SSE2 registers, generating
the result as a vector, where ~0 (all 1 bits) represents true and a zero
represents false.  eq_v4si is trivially implemented by x86_64's pcmpeqd
instruction. This patch improves the other two cases:

For v2di, gcc -O2 currently generates:

	movq    %xmm0, %rdx
        movq    %xmm1, %rax
        movdqa  %xmm0, %xmm2
        cmpq    %rax, %rdx
        movhlps %xmm2, %xmm3
        movhlps %xmm1, %xmm4
        sete    %al
        movq    %xmm3, %rdx
        movzbl  %al, %eax
        negq    %rax
        movq    %rax, %xmm0
        movq    %xmm4, %rax
        cmpq    %rax, %rdx
        sete    %al
        movzbl  %al, %eax
        negq    %rax
        movq    %rax, %xmm5
        punpcklqdq      %xmm5, %xmm0
        ret

but with this patch we now generate:

        pcmpeqd %xmm0, %xmm1
        pshufd  $177, %xmm1, %xmm0
        pand    %xmm1, %xmm0
        ret

where the results of a V4SI comparison are shuffled and bit-wise ANDed
to produce the desired result.  There's no change in the code generated
for "-O2 -msse4" where the compiler generates a single "pcmpeqq" insn.

For V1TI mode, the results are equally dramatic, where the current -O2
output looks like:

        movaps  %xmm0, -40(%rsp)
        movq    -40(%rsp), %rax
        movq    -32(%rsp), %rdx
        movaps  %xmm1, -24(%rsp)
        movq    -24(%rsp), %rcx
        movq    -16(%rsp), %rsi
        xorq    %rcx, %rax
        xorq    %rsi, %rdx
        orq     %rdx, %rax
        sete    %al
        xorl    %edx, %edx
        movzbl  %al, %eax
        negq    %rax
        adcq    $0, %rdx
        movq    %rax, %xmm2
        negq    %rdx
        movq    %rdx, -40(%rsp)
        movhps  -40(%rsp), %xmm2
        movdqa  %xmm2, %xmm0
        ret

with this patch we now generate:

        pcmpeqd %xmm0, %xmm1
        pshufd  $177, %xmm1, %xmm0
        pand    %xmm1, %xmm0
        pshufd  $78, %xmm0, %xmm1
        pand    %xmm1, %xmm0
        ret

performing a V2DI comparison, followed by a shuffle and pand, and with
-O2 -msse4 take advantages of SSE4.1's pcmpeqq:

        pcmpeqq %xmm0, %xmm1
        pshufd  $78, %xmm1, %xmm0
        pand    %xmm1, %xmm0
        ret

2022-05-13  Roger Sayle  <roger@nextmovesoftware.com>
	    Uroš Bizjak  <ubizjak@gmail.com>

gcc/ChangeLog
	* config/i386/sse.md (vec_cmpeqv2div2di): Enable for TARGET_SSE2.
	For !TARGET_SSE4_1, expand as a V4SI vector comparison, followed
	by a pshufd and pand.
	(vec_cmpeqv1tiv1ti): New define_expand implementing V1TImode
	vector equality as a V2DImode vector comparison (see above),
	followed by a pshufd and pand.

gcc/testsuite/ChangeLog
	* gcc.target/i386/sse2-v1ti-veq.c: New test case.
	* gcc.target/i386/sse2-v1ti-vne.c: New test case.

diff --git a/gcc/config/i386/sse.md b/gcc/config/i386/sse.md
index 6578104fee26eb087302c41ad2a0cf8d22c34b4c..88fc5216a589cd2d954d53a9371f14558e5c4c20 100644 (file)
--- a/gcc/config/i386/sse.md
+++ b/gcc/config/i386/sse.md
@@ -4390,13 +4390,57 @@
        (match_operator:V2DI 1 ""
          [(match_operand:V2DI 2 "register_operand")
           (match_operand:V2DI 3 "vector_operand")]))]
-  "TARGET_SSE4_1"
+  "TARGET_SSE2"
 {
-  bool ok = ix86_expand_int_vec_cmp (operands);
+  bool ok;
+  if (!TARGET_SSE4_1)
+    {
+      rtx ops[4];
+      ops[0] = gen_reg_rtx (V4SImode);
+      ops[2] = gen_lowpart (V4SImode, force_reg (V2DImode, operands[2]));
+      ops[3] = gen_lowpart (V4SImode, force_reg (V2DImode, operands[3]));
+      ops[1] = gen_rtx_fmt_ee (GET_CODE (operands[1]), V4SImode,
+                              ops[2], ops[3]);
+      ok = ix86_expand_int_vec_cmp (ops);
+
+      rtx tmp1 = gen_reg_rtx (V4SImode);
+      emit_insn (gen_sse2_pshufd (tmp1, ops[0], GEN_INT (0xb1)));
+
+      rtx tmp2 = gen_reg_rtx (V4SImode);
+      emit_insn (gen_andv4si3 (tmp2, tmp1, ops[0]));
+
+      emit_move_insn (operands[0], gen_lowpart (V2DImode, tmp2));
+    }
+  else
+    ok = ix86_expand_int_vec_cmp (operands);
   gcc_assert (ok);
   DONE;
 })
 
+(define_expand "vec_cmpeqv1tiv1ti"
+  [(set (match_operand:V1TI 0 "register_operand")
+       (match_operator:V1TI 1 ""
+         [(match_operand:V1TI 2 "register_operand")
+          (match_operand:V1TI 3 "vector_operand")]))]
+  "TARGET_SSE2"
+{
+  rtx dst = gen_reg_rtx (V2DImode);
+  rtx op1 = gen_lowpart (V2DImode, force_reg (V1TImode, operands[2]));
+  rtx op2 = gen_lowpart (V2DImode, force_reg (V1TImode, operands[3]));
+  rtx cmp = gen_rtx_fmt_ee (GET_CODE (operands[1]), V2DImode, op1, op2);
+  emit_insn (gen_vec_cmpeqv2div2di (dst, cmp, op1, op2));
+
+  rtx tmp1 = gen_reg_rtx (V4SImode);
+  rtx tmp2 = gen_lowpart (V4SImode, dst);
+  emit_insn (gen_sse2_pshufd (tmp1, tmp2, GEN_INT (0x4e)));
+
+  rtx tmp3 = gen_reg_rtx (V4SImode);
+  emit_insn (gen_andv4si3 (tmp3, tmp2, tmp1));
+
+  emit_move_insn (operands[0], gen_lowpart (V1TImode, tmp3));
+  DONE;
+})
+
 (define_expand "vcond<V_512:mode><VF_512:mode>"
   [(set (match_operand:V_512 0 "register_operand")
        (if_then_else:V_512

diff --git a/gcc/testsuite/gcc.target/i386/sse2-v1ti-veq.c b/gcc/testsuite/gcc.target/i386/sse2-v1ti-veq.c
new file mode 100644 (file)
index 0000000..b3837c4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/sse2-v1ti-veq.c
@@ -0,0 +1,12 @@
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2 -msse2" } */
+typedef unsigned __int128 uv1ti __attribute__ ((__vector_size__ (16)));
+typedef unsigned long long uv2di __attribute__ ((__vector_size__ (16)));
+typedef unsigned int uv4si __attribute__ ((__vector_size__ (16)));
+
+uv1ti eq_v1ti(uv1ti x, uv1ti y) { return x == y; }
+uv2di eq_v2di(uv2di x, uv2di y) { return x == y; }
+uv4si eq_v4si(uv4si x, uv4si y) { return x == y; }
+
+/* { dg-final { scan-assembler-times "pcmpeq" 3 } } */
+/* { dg-final { scan-assembler "pshufd" } } */

diff --git a/gcc/testsuite/gcc.target/i386/sse2-v1ti-vne.c b/gcc/testsuite/gcc.target/i386/sse2-v1ti-vne.c
new file mode 100644 (file)
index 0000000..767b0e4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/sse2-v1ti-vne.c
@@ -0,0 +1,13 @@
+/* { dg-do compile { target int128 } } */
+/* { dg-options "-O2 -msse2" } */
+typedef unsigned __int128 uv1ti __attribute__ ((__vector_size__ (16)));
+typedef unsigned long long uv2di __attribute__ ((__vector_size__ (16)));
+typedef unsigned int uv4si __attribute__ ((__vector_size__ (16)));
+
+uv1ti eq_v1ti(uv1ti x, uv1ti y) { return x != y; }
+uv2di eq_v2di(uv2di x, uv2di y) { return x != y; }
+uv4si eq_v4si(uv4si x, uv4si y) { return x != y; }
+
+/* { dg-final { scan-assembler-times "pcmpeq" 6 } } */
+/* { dg-final { scan-assembler-times "pxor" 3 } } */
+/* { dg-final { scan-assembler "pshufd" } } */