[WebAssembly] v8x16.swizzle and rewrite BUILD_VECTOR lowering

Summary:
Adds the new v8x16.swizzle SIMD instruction as specified at
https://github.com/WebAssembly/simd/blob/master/proposals/simd/SIMD.md#swizzling-using-variable-indices.
In addition to adding swizzles as a candidate lowering in
LowerBUILD_VECTOR, also rewrites and simplifies the lowering to
minimize the number of replace_lanes necessary rather than trying to
minimize code size. This leads to more uses of v128.const instead of
splats, which is expected to increase performance.

The new code will be easier to tune once V8 implements all the vector
construction operations, and it will also be easier to add new
candidate instructions in the future if necessary.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, hiraditya, sunfish, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D68527

llvm-svn: 374188

1 files changed, 165 insertions, 22 deletions

diff --git a/llvm/test/CodeGen/WebAssembly/simd-build-vector.ll b/llvm/test/CodeGen/WebAssembly/simd-build-vector.ll
index 41a320c92f7..469c50ae271 100644
--- a/llvm/test/CodeGen/WebAssembly/simd-build-vector.ll
+++ b/llvm/test/CodeGen/WebAssembly/simd-build-vector.ll
@@ -7,13 +7,12 @@
 target datalayout = "e-m:e-p:32:32-i64:64-n32:64-S128"
 target triple = "wasm32-unknown-unknown"
 
-; CHECK-LABEL: same_const_one_replaced_i8x16:
-; CHECK-NEXT:  .functype       same_const_one_replaced_i8x16 (i32) -> (v128)
-; CHECK-NEXT:  i32.const       $push[[L0:[0-9]+]]=, 42
-; CHECK-NEXT:  i16x8.splat     $push[[L1:[0-9]+]]=, $pop[[L0]]
-; CHECK-NEXT:  i16x8.replace_lane      $push[[L2:[0-9]+]]=, $pop[[L1]], 5, $0
-; CHECK-NEXT:  return          $pop[[L2]]
-define <8 x i16> @same_const_one_replaced_i8x16(i16 %x) {
+; CHECK-LABEL: same_const_one_replaced_i16x8:
+; CHECK-NEXT:  .functype       same_const_one_replaced_i16x8 (i32) -> (v128)
+; CHECK-NEXT:  v128.const      $push[[L0:[0-9]+]]=, 42, 42, 42, 42, 42, 0, 42, 42
+; CHECK-NEXT:  i16x8.replace_lane      $push[[L1:[0-9]+]]=, $pop[[L0]], 5, $0
+; CHECK-NEXT:  return          $pop[[L1]]
+define <8 x i16> @same_const_one_replaced_i16x8(i16 %x) {
   %v = insertelement
     <8 x i16> <i16 42, i16 42, i16 42, i16 42, i16 42, i16 42, i16 42, i16 42>,
     i16 %x,
@@ -21,12 +20,12 @@ define <8 x i16> @same_const_one_replaced_i8x16(i16 %x) {
   ret <8 x i16> %v
 }
 
-; CHECK-LABEL: different_const_one_replaced_i8x16:
-; CHECK-NEXT:  .functype       different_const_one_replaced_i8x16 (i32) -> (v128)
+; CHECK-LABEL: different_const_one_replaced_i16x8:
+; CHECK-NEXT:  .functype       different_const_one_replaced_i16x8 (i32) -> (v128)
 ; CHECK-NEXT:  v128.const      $push[[L0:[0-9]+]]=, 1, -2, 3, -4, 5, 0, 7, -8
 ; CHECK-NEXT:  i16x8.replace_lane      $push[[L1:[0-9]+]]=, $pop[[L0]], 5, $0
 ; CHECK-NEXT:  return          $pop[[L1]]
-define <8 x i16> @different_const_one_replaced_i8x16(i16 %x) {
+define <8 x i16> @different_const_one_replaced_i16x8(i16 %x) {
   %v = insertelement
     <8 x i16> <i16 1, i16 -2, i16 3, i16 -4, i16 5, i16 -6, i16 7, i16 -8>,
     i16 %x,
@@ -36,10 +35,9 @@ define <8 x i16> @different_const_one_replaced_i8x16(i16 %x) {
 
 ; CHECK-LABEL: same_const_one_replaced_f32x4:
 ; CHECK-NEXT:  .functype       same_const_one_replaced_f32x4 (f32) -> (v128)
-; CHECK-NEXT:  f32.const       $push[[L0:[0-9]+]]=, 0x1.5p5
-; CHECK-NEXT:  f32x4.splat     $push[[L1:[0-9]+]]=, $pop[[L0]]
-; CHECK-NEXT:  f32x4.replace_lane      $push[[L2:[0-9]+]]=, $pop[[L1]], 2, $0
-; CHECK-NEXT:  return          $pop[[L2]]
+; CHECK-NEXT:  v128.const      $push[[L0:[0-9]+]]=, 0x1.5p5, 0x1.5p5, 0x0p0, 0x1.5p5
+; CHECK-NEXT:  f32x4.replace_lane      $push[[L1:[0-9]+]]=, $pop[[L0]], 2, $0
+; CHECK-NEXT:  return          $pop[[L1]]
 define <4 x float> @same_const_one_replaced_f32x4(float %x) {
   %v = insertelement
     <4 x float> <float 42., float 42., float 42., float 42.>,
@@ -63,11 +61,8 @@ define <4 x float> @different_const_one_replaced_f32x4(float %x) {
 
 ; CHECK-LABEL: splat_common_const_i32x4:
 ; CHECK-NEXT:  .functype       splat_common_const_i32x4 () -> (v128)
-; CHECK-NEXT:  i32.const       $push[[L0:[0-9]+]]=, 3
-; CHECK-NEXT:  i32x4.splat     $push[[L1:[0-9]+]]=, $pop[[L0]]
-; CHECK-NEXT:  i32.const       $push[[L2:[0-9]+]]=, 1
-; CHECK-NEXT:  i32x4.replace_lane      $push[[L3:[0-9]+]]=, $pop[[L1]], 3, $pop[[L2]]
-; CHECK-NEXT:  return          $pop[[L3]]
+; CHECK-NEXT:  v128.const      $push[[L0:[0-9]+]]=, 0, 3, 3, 1
+; CHECK-NEXT:  return          $pop[[L0]]
 define <4 x i32> @splat_common_const_i32x4() {
   ret <4 x i32> <i32 undef, i32 3, i32 3, i32 1>
 }
@@ -92,11 +87,159 @@ define <8 x i16> @splat_common_arg_i16x8(i16 %a, i16 %b, i16 %c) {
   ret <8 x i16> %v7
 }
 
+; CHECK-LABEL: swizzle_one_i8x16:
+; CHECK-NEXT:  .functype       swizzle_one_i8x16 (v128, v128) -> (v128)
+; CHECK-NEXT:  v8x16.swizzle   $push[[L0:[0-9]+]]=, $0, $1
+; CHECK-NEXT:  return          $pop[[L0]]
+define <16 x i8> @swizzle_one_i8x16(<16 x i8> %src, <16 x i8> %mask) {
+  %m0 = extractelement <16 x i8> %mask, i32 0
+  %s0 = extractelement <16 x i8> %src, i8 %m0
+  %v0 = insertelement <16 x i8> undef, i8 %s0, i32 0
+  ret <16 x i8> %v0
+}
+
+; CHECK-LABEL: swizzle_all_i8x16:
+; CHECK-NEXT:  .functype       swizzle_all_i8x16 (v128, v128) -> (v128)
+; CHECK-NEXT:  v8x16.swizzle   $push[[L0:[0-9]+]]=, $0, $1
+; CHECK-NEXT:  return          $pop[[L0]]
+define <16 x i8> @swizzle_all_i8x16(<16 x i8> %src, <16 x i8> %mask) {
+  %m0 = extractelement <16 x i8> %mask, i32 0
+  %s0 = extractelement <16 x i8> %src, i8 %m0
+  %v0 = insertelement <16 x i8> undef, i8 %s0, i32 0
+  %m1 = extractelement <16 x i8> %mask, i32 1
+  %s1 = extractelement <16 x i8> %src, i8 %m1
+  %v1 = insertelement <16 x i8> %v0, i8 %s1, i32 1
+  %m2 = extractelement <16 x i8> %mask, i32 2
+  %s2 = extractelement <16 x i8> %src, i8 %m2
+  %v2 = insertelement <16 x i8> %v1, i8 %s2, i32 2
+  %m3 = extractelement <16 x i8> %mask, i32 3
+  %s3 = extractelement <16 x i8> %src, i8 %m3
+  %v3 = insertelement <16 x i8> %v2, i8 %s3, i32 3
+  %m4 = extractelement <16 x i8> %mask, i32 4
+  %s4 = extractelement <16 x i8> %src, i8 %m4
+  %v4 = insertelement <16 x i8> %v3, i8 %s4, i32 4
+  %m5 = extractelement <16 x i8> %mask, i32 5
+  %s5 = extractelement <16 x i8> %src, i8 %m5
+  %v5 = insertelement <16 x i8> %v4, i8 %s5, i32 5
+  %m6 = extractelement <16 x i8> %mask, i32 6
+  %s6 = extractelement <16 x i8> %src, i8 %m6
+  %v6 = insertelement <16 x i8> %v5, i8 %s6, i32 6
+  %m7 = extractelement <16 x i8> %mask, i32 7
+  %s7 = extractelement <16 x i8> %src, i8 %m7
+  %v7 = insertelement <16 x i8> %v6, i8 %s7, i32 7
+  %m8 = extractelement <16 x i8> %mask, i32 8
+  %s8 = extractelement <16 x i8> %src, i8 %m8
+  %v8 = insertelement <16 x i8> %v7, i8 %s8, i32 8
+  %m9 = extractelement <16 x i8> %mask, i32 9
+  %s9 = extractelement <16 x i8> %src, i8 %m9
+  %v9 = insertelement <16 x i8> %v8, i8 %s9, i32 9
+  %m10 = extractelement <16 x i8> %mask, i32 10
+  %s10 = extractelement <16 x i8> %src, i8 %m10
+  %v10 = insertelement <16 x i8> %v9, i8 %s10, i32 10
+  %m11 = extractelement <16 x i8> %mask, i32 11
+  %s11 = extractelement <16 x i8> %src, i8 %m11
+  %v11 = insertelement <16 x i8> %v10, i8 %s11, i32 11
+  %m12 = extractelement <16 x i8> %mask, i32 12
+  %s12 = extractelement <16 x i8> %src, i8 %m12
+  %v12 = insertelement <16 x i8> %v11, i8 %s12, i32 12
+  %m13 = extractelement <16 x i8> %mask, i32 13
+  %s13 = extractelement <16 x i8> %src, i8 %m13
+  %v13 = insertelement <16 x i8> %v12, i8 %s13, i32 13
+  %m14 = extractelement <16 x i8> %mask, i32 14
+  %s14 = extractelement <16 x i8> %src, i8 %m14
+  %v14 = insertelement <16 x i8> %v13, i8 %s14, i32 14
+  %m15 = extractelement <16 x i8> %mask, i32 15
+  %s15 = extractelement <16 x i8> %src, i8 %m15
+  %v15 = insertelement <16 x i8> %v14, i8 %s15, i32 15
+  ret <16 x i8> %v15
+}
+
+; CHECK-LABEL: swizzle_one_i16x8:
+; CHECK-NEXT:  .functype       swizzle_one_i16x8 (v128, v128) -> (v128)
+; CHECK-NOT:    swizzle
+; CHECK:        return
+define <8 x i16> @swizzle_one_i16x8(<8 x i16> %src, <8 x i16> %mask) {
+  %m0 = extractelement <8 x i16> %mask, i32 0
+  %s0 = extractelement <8 x i16> %src, i16 %m0
+  %v0 = insertelement <8 x i16> undef, i16 %s0, i32 0
+  ret <8 x i16> %v0
+}
+
+; CHECK-LABEL: mashup_swizzle_i8x16:
+; CHECK-NEXT:  .functype       mashup_swizzle_i8x16 (v128, v128, i32) -> (v128)
+; CHECK-NEXT:  v8x16.swizzle   $push[[L0:[0-9]+]]=, $0, $1
+; CHECK:       i8x16.replace_lane
+; CHECK:       i8x16.replace_lane
+; CHECK:       i8x16.replace_lane
+; CHECK:       i8x16.replace_lane
+; CHECK:       return
+define <16 x i8> @mashup_swizzle_i8x16(<16 x i8> %src, <16 x i8> %mask, i8 %splatted) {
+  ; swizzle 0
+  %m0 = extractelement <16 x i8> %mask, i32 0
+  %s0 = extractelement <16 x i8> %src, i8 %m0
+  %v0 = insertelement <16 x i8> undef, i8 %s0, i32 0
+  ; swizzle 7
+  %m1 = extractelement <16 x i8> %mask, i32 7
+  %s1 = extractelement <16 x i8> %src, i8 %m1
+  %v1 = insertelement <16 x i8> %v0, i8 %s1, i32 7
+  ; splat 3
+  %v2 = insertelement <16 x i8> %v1, i8 %splatted, i32 3
+  ; splat 12
+  %v3 = insertelement <16 x i8> %v2, i8 %splatted, i32 12
+  ; const 4
+  %v4 = insertelement <16 x i8> %v3, i8 42, i32 4
+  ; const 14
+  %v5 = insertelement <16 x i8> %v4, i8 42, i32 14
+  ret <16 x i8> %v5
+}
+
+; CHECK-LABEL: mashup_const_i8x16:
+; CHECK-NEXT:  .functype       mashup_const_i8x16 (v128, v128, i32) -> (v128)
+; CHECK:       v128.const      $push[[L0:[0-9]+]]=, 0, 0, 0, 0, 42, 0, 0, 0, 0, 0, 0, 0, 0, 0, 42, 0
+; CHECK:       i8x16.replace_lane
+; CHECK:       i8x16.replace_lane
+; CHECK:       i8x16.replace_lane
+; CHECK:       return
+define <16 x i8> @mashup_const_i8x16(<16 x i8> %src, <16 x i8> %mask, i8 %splatted) {
+  ; swizzle 0
+  %m0 = extractelement <16 x i8> %mask, i32 0
+  %s0 = extractelement <16 x i8> %src, i8 %m0
+  %v0 = insertelement <16 x i8> undef, i8 %s0, i32 0
+  ; splat 3
+  %v1 = insertelement <16 x i8> %v0, i8 %splatted, i32 3
+  ; splat 12
+  %v2 = insertelement <16 x i8> %v1, i8 %splatted, i32 12
+  ; const 4
+  %v3 = insertelement <16 x i8> %v2, i8 42, i32 4
+  ; const 14
+  %v4 = insertelement <16 x i8> %v3, i8 42, i32 14
+  ret <16 x i8> %v4
+}
+
+; CHECK-LABEL: mashup_splat_i8x16:
+; CHECK-NEXT:  .functype       mashup_splat_i8x16 (v128, v128, i32) -> (v128)
+; CHECK:       i8x16.splat     $push[[L0:[0-9]+]]=, $2
+; CHECK:       i8x16.replace_lane
+; CHECK:       i8x16.replace_lane
+; CHECK:       return
+define <16 x i8> @mashup_splat_i8x16(<16 x i8> %src, <16 x i8> %mask, i8 %splatted) {
+  ; swizzle 0
+  %m0 = extractelement <16 x i8> %mask, i32 0
+  %s0 = extractelement <16 x i8> %src, i8 %m0
+  %v0 = insertelement <16 x i8> undef, i8 %s0, i32 0
+  ; splat 3
+  %v1 = insertelement <16 x i8> %v0, i8 %splatted, i32 3
+  ; splat 12
+  %v2 = insertelement <16 x i8> %v1, i8 %splatted, i32 12
+  ; const 4
+  %v3 = insertelement <16 x i8> %v2, i8 42, i32 4
+  ret <16 x i8> %v3
+}
+
 ; CHECK-LABEL: undef_const_insert_f32x4:
 ; CHECK-NEXT:  .functype       undef_const_insert_f32x4 () -> (v128)
-; CHECK-NEXT:  f32.const       $push[[L0:[0-9]+]]=, 0x1.5p5
-; CHECK-NEXT:  f32x4.splat     $push[[L1:[0-9]+]]=, $pop[[L0]]
-; CHECK-NEXT:  return          $pop[[L1]]
+; CHECK-NEXT:  v128.const      $push[[L0:[0-9]+]]=, 0x0p0, 0x1.5p5, 0x0p0, 0x0p0
+; CHECK-NEXT:  return          $pop[[L0]]
 define <4 x float> @undef_const_insert_f32x4() {
   %v = insertelement <4 x float> undef, float 42., i32 1
   ret <4 x float> %v