From: Nicolai Hähnle <nicolai.haeh...@amd.com>
---
.../drivers/radeon/radeon_setup_tgsi_llvm.c | 29 ++++++++++++++--------
1 file changed, 19 insertions(+), 10 deletions(-)
diff --git a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
index 22ff18e..e4bfa74 100644
--- a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
+++ b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
@@ -437,33 +437,42 @@ static void emit_declaration(struct lp_build_tgsi_context
*bld_base,
decl_size = 4 * ((last - first) + 1);
if (decl->Declaration.Array) {
unsigned id = decl->Array.ArrayID - 1;
if (!ctx->arrays) {
int size =
bld_base->info->array_max[TGSI_FILE_TEMPORARY];
ctx->arrays = CALLOC(size,
sizeof(ctx->arrays[0]));
}
ctx->arrays[id].range = decl->Range;
- /* If the array is more than 16 elements (each element
- * is 32-bits), then store it in a vector. Storing the
- * array in a vector will causes the compiler to store
- * the array in registers and access it using indirect
- * addressing. 16 is number of vector elements that
- * LLVM will store in a register.
- * FIXME: We shouldn't need to do this. LLVM should be
- * smart enough to promote allocas int registers when
- * profitable.
+ /* If the array has more than 16 elements, store it
+ * in memory using an alloca that spans the entire
+ * array.
+ *
+ * Otherwise, store each array element individually.
+ * We will then generate vectors (per-channel, up to
+ * <4 x float>) for indirect addressing.
+ *
+ * Note that 16 is the number of vector elements that
+ * LLVM will store in a register, so theoretically an
+ * array with up to 4 * 16 = 64 elements could be
+ * handled this way, but whether that's a good idea
+ * depends on VGPR register pressure elsewhere.
+ *
+ * FIXME: We shouldn't need to have the non-alloca
+ * code path for arrays. LLVM should be smart enough to
+ * promote allocas into registers when profitable.
*/
if (decl_size > 16) {
array_alloca = LLVMBuildAlloca(builder,
- LLVMArrayType(bld_base->base.vec_type,
decl_size),"array");
+ LLVMArrayType(bld_base->base.vec_type,
+ decl_size), "array");
ctx->arrays[id].alloca = array_alloca;
}
}
if (!ctx->temps_count) {
ctx->temps_count =
bld_base->info->file_max[TGSI_FILE_TEMPORARY] + 1;
ctx->temps = MALLOC(TGSI_NUM_CHANNELS *
ctx->temps_count * sizeof(LLVMValueRef));
}
if (!array_alloca) {
for (i = 0; i < decl_size; ++i) {
--
2.7.4
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