Add gen_(const_)vec_duplicate helpers

This patch adds helper functions for generating constant and
non-constant vector duplicates.  These routines help with SVE because
it is then easier to use:

   (const:M (vec_duplicate:M X))

for a broadcast of X, even if the number of elements in M isn't known
at compile time.  It also makes it easier for general rtx code to treat
constant and non-constant duplicates in the same way.

In the target code, the patch uses gen_vec_duplicate instead of
gen_rtx_VEC_DUPLICATE if handling constants correctly is potentially
useful.  It might be that some or all of the call sites only handle
non-constants in practice, in which case the change is a harmless
no-op (and a saving of a few characters).

Otherwise, the target changes use gen_const_vec_duplicate instead
of gen_rtx_CONST_VECTOR if the constant is obviously a duplicate.
They also include some changes to use CONSTxx_RTX for easy global
constants.

2017-11-01  Richard Sandiford  <richard.sandiford@linaro.org>
	    Alan Hayward  <alan.hayward@arm.com>
	    David Sherwood  <david.sherwood@arm.com>

gcc/
	* emit-rtl.h (gen_const_vec_duplicate): Declare.
	(gen_vec_duplicate): Likewise.
	* emit-rtl.c (gen_const_vec_duplicate_1): New function, split
	out from...
	(gen_const_vector): ...here.
	(gen_const_vec_duplicate, gen_vec_duplicate): New functions.
	(gen_rtx_CONST_VECTOR): Use gen_const_vec_duplicate for constants
	whose elements are all equal.
	* optabs.c (expand_vector_broadcast): Use gen_const_vec_duplicate.
	* simplify-rtx.c (simplify_const_unary_operation): Likewise.
	(simplify_relational_operation): Likewise.
	* config/aarch64/aarch64.c (aarch64_simd_gen_const_vector_dup):
	Likewise.
	(aarch64_simd_dup_constant): Use gen_vec_duplicate.
	(aarch64_expand_vector_init): Likewise.
	* config/arm/arm.c (neon_vdup_constant): Likewise.
	(neon_expand_vector_init): Likewise.
	(arm_expand_vec_perm): Use gen_const_vec_duplicate.
	(arm_block_set_unaligned_vect): Likewise.
	(arm_block_set_aligned_vect): Likewise.
	* config/arm/neon.md (neon_copysignf<mode>): Likewise.
	* config/i386/i386.c (ix86_expand_vec_perm): Likewise.
	(expand_vec_perm_even_odd_pack): Likewise.
	(ix86_vector_duplicate_value): Use gen_vec_duplicate.
	* config/i386/sse.md (one_cmpl<mode>2): Use CONSTM1_RTX.
	* config/ia64/ia64.c (ia64_expand_vecint_compare): Use
	gen_const_vec_duplicate.
	* config/ia64/vect.md (addv2sf3, subv2sf3): Use CONST1_RTX.
	* config/mips/mips.c (mips_gen_const_int_vector): Use
	gen_const_vec_duplicate.
	(mips_expand_vector_init): Use CONST0_RTX.
	* config/powerpcspe/altivec.md (abs<mode>2, nabs<mode>2): Likewise.
	(define_split): Use gen_const_vec_duplicate.
	* config/rs6000/altivec.md (abs<mode>2, nabs<mode>2): Use CONST0_RTX.
	(define_split): Use gen_const_vec_duplicate.
	* config/s390/vx-builtins.md (vec_genmask<mode>): Likewise.
	(vec_ctd_s64, vec_ctd_u64, vec_ctsl, vec_ctul): Likewise.
	* config/spu/spu.c (spu_const): Likewise.

Co-Authored-By: Alan Hayward <alan.hayward@arm.com>
Co-Authored-By: David Sherwood <david.sherwood@arm.com>

From-SVN: r254292

1 files changed, 3 insertions, 25 deletions

diff --git a/gcc/config/powerpcspe/altivec.md b/gcc/config/powerpcspe/altivec.md
index e98309a..f1cc6e2 100644
--- a/gcc/config/powerpcspe/altivec.md
+++ b/gcc/config/powerpcspe/altivec.md
@@ -352,12 +352,10 @@
   HOST_WIDE_INT val = const_vector_elt_as_int (op1, elt);
   rtx rtx_val = GEN_INT (val);
   int shift = vspltis_shifted (op1);
-  int nunits = GET_MODE_NUNITS (<MODE>mode);
-  int i;
 
   gcc_assert (shift != 0);
   operands[2] = gen_reg_rtx (<MODE>mode);
-  operands[3] = gen_rtx_CONST_VECTOR (<MODE>mode, rtvec_alloc (nunits));
+  operands[3] = gen_const_vec_duplicate (<MODE>mode, rtx_val);
   operands[4] = gen_reg_rtx (<MODE>mode);
 
   if (shift < 0)
@@ -370,10 +368,6 @@
       operands[5] = CONST0_RTX (<MODE>mode);
       operands[6] = GEN_INT (shift);
     }
-
-  /* Populate the constant vectors.  */
-  for (i = 0; i < nunits; i++)
-    XVECEXP (operands[3], 0, i) = rtx_val;
 })
 
 (define_insn "get_vrsave_internal"
@@ -2752,15 +2746,8 @@
         (smax:VI2 (match_dup 1) (match_dup 4)))]
   "<VI_unit>"
 {
-  int i, n_elt = GET_MODE_NUNITS (<MODE>mode);
-  rtvec v = rtvec_alloc (n_elt);
-
-  /* Create an all 0 constant.  */
-  for (i = 0; i < n_elt; ++i)
-    RTVEC_ELT (v, i) = const0_rtx;
-
   operands[2] = gen_reg_rtx (<MODE>mode);
-  operands[3] = gen_rtx_CONST_VECTOR (<MODE>mode, v);
+  operands[3] = CONST0_RTX (<MODE>mode);
   operands[4] = gen_reg_rtx (<MODE>mode);
 })
 
@@ -2777,17 +2764,8 @@
         (smin:VI2 (match_dup 1) (match_dup 4)))]
   "<VI_unit>"
 {
-  int i;
-  int n_elt = GET_MODE_NUNITS (<MODE>mode);
-
-  rtvec v = rtvec_alloc (n_elt);
-
-  /* Create an all 0 constant.  */
-  for (i = 0; i < n_elt; ++i)
-    RTVEC_ELT (v, i) = const0_rtx;
-
   operands[2] = gen_reg_rtx (<MODE>mode);
-  operands[3] = gen_rtx_CONST_VECTOR (<MODE>mode, v);
+  operands[3] = CONST0_RTX (<MODE>mode);
   operands[4] = gen_reg_rtx (<MODE>mode);
 })