From e4e52b06a9dec7d076ceeb4469bb2ca8b37c6cd5 Mon Sep 17 00:00:00 2001
From: Lyude <lyude@redhat.com>
Date: Tue, 2 May 2017 17:05:50 -0400
Subject: [PATCH] Revert "draw: use SoA fetch, not AoS one"

This reverts commit e827d9175675aaa6cfc0b981e2a80685fb7b3a74.

Signed-off-by: Lyude <lyude@redhat.com>
---
 src/gallium/auxiliary/draw/draw_llvm.c | 71 +++++++++++++++++++++++-----------
 1 file changed, 48 insertions(+), 23 deletions(-)

diff --git a/src/gallium/auxiliary/draw/draw_llvm.c b/src/gallium/auxiliary/draw/draw_llvm.c
index 8952dc8..19b75a5 100644
--- a/src/gallium/auxiliary/draw/draw_llvm.c
+++ b/src/gallium/auxiliary/draw/draw_llvm.c
@@ -713,6 +713,39 @@ fetch_instanced(struct gallivm_state *gallivm,
 
 
 static void
+convert_to_soa(struct gallivm_state *gallivm,
+               LLVMValueRef src_aos[LP_MAX_VECTOR_WIDTH / 32],
+               LLVMValueRef dst_soa[TGSI_NUM_CHANNELS],
+               const struct lp_type soa_type)
+{
+   unsigned j, k;
+   struct lp_type aos_channel_type = soa_type;
+
+   LLVMValueRef aos_channels[TGSI_NUM_CHANNELS];
+   unsigned pixels_per_channel = soa_type.length / TGSI_NUM_CHANNELS;
+
+   debug_assert(TGSI_NUM_CHANNELS == 4);
+   debug_assert((soa_type.length % TGSI_NUM_CHANNELS) == 0);
+
+   aos_channel_type.length >>= 1;
+
+   for (j = 0; j < TGSI_NUM_CHANNELS; ++j) {
+      LLVMValueRef channel[LP_MAX_VECTOR_LENGTH] = { 0 };
+
+      assert(pixels_per_channel <= LP_MAX_VECTOR_LENGTH);
+
+      for (k = 0; k < pixels_per_channel; ++k) {
+         channel[k] = src_aos[j + TGSI_NUM_CHANNELS * k];
+      }
+
+      aos_channels[j] = lp_build_concat(gallivm, channel, aos_channel_type, pixels_per_channel);
+   }
+
+   lp_build_transpose_aos(gallivm, soa_type, aos_channels, dst_soa);
+}
+
+
+static void
 fetch_vector(struct gallivm_state *gallivm,
              const struct util_format_description *format_desc,
              struct lp_type vs_type,
@@ -722,10 +755,11 @@ fetch_vector(struct gallivm_state *gallivm,
              LLVMValueRef *inputs,
              LLVMValueRef indices)
 {
+   LLVMValueRef zero = LLVMConstNull(LLVMInt32TypeInContext(gallivm->context));
    LLVMBuilderRef builder = gallivm->builder;
    struct lp_build_context blduivec;
-   struct lp_type fetch_type = vs_type;
    LLVMValueRef offset, valid_mask;
+   LLVMValueRef aos_fetch[LP_MAX_VECTOR_WIDTH / 32];
    unsigned i;
 
    lp_build_context_init(&blduivec, gallivm, lp_uint_type(vs_type));
@@ -749,37 +783,28 @@ fetch_vector(struct gallivm_state *gallivm,
    }
 
    /*
-    * Unlike fetch_instanced, use SoA fetch instead of multiple AoS fetches.
-    * This should always produce better code.
+    * Note: we probably really want to use SoA fetch, not AoS one (albeit
+    * for most formats it will amount to the same as this isn't very
+    * optimized). But looks dangerous since it assumes alignment.
     */
+   for (i = 0; i < vs_type.length; i++) {
+      LLVMValueRef offset1, elem;
+      elem = lp_build_const_int32(gallivm, i);
+      offset1 = LLVMBuildExtractElement(builder, offset, elem, "");
 
-   /* The type handling is annoying here... */
-   if (format_desc->colorspace == UTIL_FORMAT_COLORSPACE_RGB &&
-       format_desc->channel[0].pure_integer) {
-      if (format_desc->channel[0].type == UTIL_FORMAT_TYPE_SIGNED) {
-         fetch_type = lp_type_int_vec(vs_type.width, vs_type.width * vs_type.length);
-      }
-      else if (format_desc->channel[0].type == UTIL_FORMAT_TYPE_UNSIGNED) {
-         fetch_type = lp_type_uint_vec(vs_type.width, vs_type.width * vs_type.length);
-      }
-   }
-
-   lp_build_fetch_rgba_soa(gallivm, format_desc,
-                           fetch_type, FALSE, map_ptr, offset,
-                           blduivec.zero, blduivec.zero,
-                           NULL, inputs);
-
-   for (i = 0; i < TGSI_NUM_CHANNELS; i++) {
-      inputs[i] = LLVMBuildBitCast(builder, inputs[i],
-                                   lp_build_vec_type(gallivm, vs_type), "");
+      aos_fetch[i] = lp_build_fetch_rgba_aos(gallivm, format_desc,
+                                             lp_float32_vec4_type(),
+                                             FALSE, map_ptr, offset1,
+                                             zero, zero, NULL);
    }
+   convert_to_soa(gallivm, aos_fetch, inputs, vs_type);
 
-   /* out-of-bound fetches return all zeros */
    for (i = 0; i < TGSI_NUM_CHANNELS; i++) {
       inputs[i] = LLVMBuildBitCast(builder, inputs[i], blduivec.vec_type, "");
       inputs[i] = LLVMBuildAnd(builder, inputs[i], valid_mask, "");
       inputs[i] = LLVMBuildBitCast(builder, inputs[i],
                                    lp_build_vec_type(gallivm, vs_type), "");
+
    }
 }
 
-- 
2.9.3