[AArch64] Support zero-extended move to FP register

The popcount expansion uses SIMD instructions acting on 64-bit values.
As a result a popcount of a 32-bit integer requires zero-extension before 
moving the zero-extended value into an FP register.  This patch adds
support for zero-extended int->FP moves to avoid the redundant uxtw.
Similarly, add support for 32-bit zero-extending load->FP register
and 32-bit zero-extending FP->FP and FP->int moves.
Add a missing 'fp' arch attribute to the related 8/16-bit pattern and
fix an incorrect type attribute.

To complete zero-extended load support, add a new alternative to 
load_pair_zero_extendsidi2_aarch64 to support LDP into FP registers too.

int f (int a)
{
  return __builtin_popcount (a);
}

Before:
	uxtw	x0, w0
	fmov	d0, x0
	cnt	v0.8b, v0.8b
	addv	b0, v0.8b
	fmov	w0, s0
	ret

After:
	fmov	s0, w0
	cnt	v0.8b, v0.8b
	addv	b0, v0.8b
	fmov	w0, s0
	ret

Passes regress & bootstrap on AArch64.

    gcc/
	* config/aarch64/aarch64.md (zero_extendsidi2_aarch64): Add alternatives
	to zero-extend between int and floating-point registers.
	(load_pair_zero_extendsidi2_aarch64): Add alternative for zero-extended
	ldp into floating-point registers.  Add type and arch attributes.
	(zero_extend<SHORT:mode><GPI:mode>2_aarch64): Add arch attribute.
	Use f_loads for type attribute.

    testsuite/
	* gcc.target/aarch64/popcnt.c: Test zero-extended popcount.
	* gcc.target/aarch64/vec_zeroextend.c: Test zero-extended vectors.

From-SVN: r265079

gcc/ChangeLog

+2018-10-12  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	* config/aarch64/aarch64.md (zero_extendsidi2_aarch64): Add alternatives
+	to zero-extend between int and floating-point registers.
+	(load_pair_zero_extendsidi2_aarch64): Add alternative for zero-extended
+	ldp into floating-point registers.  Add type and arch attributes.
+	(zero_extend<SHORT:mode><GPI:mode>2_aarch64): Add arch attribute.
+	Use f_loads for type attribute.
+
 2018-10-11  Martin Sebor  <msebor@redhat.com>
 
 	* doc/extend.texi (attribute packed): Correct typos.

gcc/config/aarch64/aarch64.md

@@ -1520,26 +1520,34 @@
 )
 
 (define_insn "*zero_extendsidi2_aarch64"
-  [(set (match_operand:DI 0 "register_operand" "=r,r")
-        (zero_extend:DI (match_operand:SI 1 "nonimmediate_operand" "r,m")))]
+  [(set (match_operand:DI 0 "register_operand" "=r,r,w,w,r,w")
+        (zero_extend:DI (match_operand:SI 1 "nonimmediate_operand" "r,m,r,m,w,w")))]
   ""
   "@
    uxtw\t%0, %w1
-   ldr\t%w0, %1"
-  [(set_attr "type" "extend,load_4")]
+   ldr\t%w0, %1
+   fmov\t%s0, %w1
+   ldr\t%s0, %1
+   fmov\t%w0, %s1
+   fmov\t%s0, %s1"
+  [(set_attr "type" "extend,load_4,f_mcr,f_loads,f_mrc,fmov")
+   (set_attr "arch" "*,*,fp,fp,fp,fp")]
 )
 
 (define_insn "*load_pair_zero_extendsidi2_aarch64"
-  [(set (match_operand:DI 0 "register_operand" "=r")
-	(zero_extend:DI (match_operand:SI 1 "aarch64_mem_pair_operand" "Ump")))
-   (set (match_operand:DI 2 "register_operand" "=r")
-	(zero_extend:DI (match_operand:SI 3 "memory_operand" "m")))]
+  [(set (match_operand:DI 0 "register_operand" "=r,w")
+	(zero_extend:DI (match_operand:SI 1 "aarch64_mem_pair_operand" "Ump,Ump")))
+   (set (match_operand:DI 2 "register_operand" "=r,w")
+	(zero_extend:DI (match_operand:SI 3 "memory_operand" "m,m")))]
   "rtx_equal_p (XEXP (operands[3], 0),
 		plus_constant (Pmode,
 			       XEXP (operands[1], 0),
 			       GET_MODE_SIZE (SImode)))"
-  "ldp\\t%w0, %w2, %1"
-  [(set_attr "type" "load_8")]
+  "@
+   ldp\t%w0, %w2, %1
+   ldp\t%s0, %s2, %1"
+  [(set_attr "type" "load_8,neon_load1_2reg")
+   (set_attr "arch" "*,fp")]
 )
 
 (define_expand "<ANY_EXTEND:optab><SHORT:mode><GPI:mode>2"
@@ -1566,7 +1574,8 @@
    and\t%<GPI:w>0, %<GPI:w>1, <SHORT:short_mask>
    ldr<SHORT:size>\t%w0, %1
    ldr\t%<SHORT:size>0, %1"
-  [(set_attr "type" "logic_imm,load_4,load_4")]
+  [(set_attr "type" "logic_imm,load_4,f_loads")
+   (set_attr "arch" "*,*,fp")]
 )
 
 (define_expand "<optab>qihi2"

gcc/testsuite/ChangeLog

+2018-10-12  Wilco Dijkstra  <wdijkstr@arm.com>
+
+	* gcc.target/aarch64/popcnt.c: Test zero-extended popcount.
+	* gcc.target/aarch64/vec_zeroextend.c: Test zero-extended vectors.
+
 2018-10-11  Will Schmidt  <will_schmidt@vnet.ibm.com>
 
 	* gcc.target/powerpc/fold-vec-insert-char-p8.c: New.

gcc/testsuite/gcc.target/aarch64/popcnt.c

@@ -19,5 +19,16 @@ foo2 (long long x)
   return __builtin_popcountll (x);
 }
 
-/* { dg-final { scan-assembler-not "popcount" } } */
-/* { dg-final { scan-assembler-times "cnt\t" 3 } } */
+int
+foo3 (int *p)
+{
+  return __builtin_popcount (*p);
+}
+
+/* { dg-final { scan-assembler-not {popcount} } } */
+/* { dg-final { scan-assembler-times {cnt\t} 4 } } */
+/* { dg-final { scan-assembler-times {fmov\ts} 1 {target lp64} } } */
+/* { dg-final { scan-assembler-times {fmov\td} 2 {target lp64} } } */
+/* { dg-final { scan-assembler-times {fmov\ts} 2 {target ilp32} } } */
+/* { dg-final { scan-assembler-times {fmov\td} 1 {target ilp32} } } */
+/* { dg-final { scan-assembler-times {ldr\ts} 1 } } */

gcc/testsuite/gcc.target/aarch64/vec_zeroextend.c

+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+
+#define vector __attribute__((vector_size(16) ))
+
+vector unsigned long long
+f1(vector unsigned long long b, vector unsigned int a)
+{
+  b[0] = a[0];
+  return b;
+}
+
+unsigned long long
+f2(vector unsigned int a)
+{
+  return a[0];
+}
+
+/* { dg-final { scan-assembler-times {fmov} 2 } } */
+/* { dg-final { scan-assembler-not {umov} } } */
+/* { dg-final { scan-assembler-not {uxtw} } } */