radeonsi: load the streamout buf descriptors closer to their use

LLVM can still decide to hoist the loads since they're marked invariant.

Reviewed-by: Marek Olšák <marek.olsak@amd.com>

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index 576363eb631648e85f6f80686c0517163cd44a80..601085ddbde1b2ee834fde13e688479b9429c9a0 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -2274,19 +2274,6 @@ static void si_llvm_emit_streamout(struct si_shader_context *ctx,
        LLVMBuilderRef builder = gallivm->builder;
        int i;
        struct lp_build_if_state if_ctx;
-       LLVMValueRef so_buffers[4];
-       LLVMValueRef buf_ptr = LLVMGetParam(ctx->main_fn,
-                                           SI_PARAM_RW_BUFFERS);
-
-       /* Load the descriptors. */
-       for (i = 0; i < 4; ++i) {
-               if (ctx->shader->selector->so.stride[i]) {
-                       LLVMValueRef offset = lp_build_const_int32(gallivm,
-                                                                  SI_VS_STREAMOUT_BUF0 + i);
-
-                       so_buffers[i] = build_indexed_load_const(ctx, buf_ptr, offset);
-               }
-       }
 
        /* Get bits [22:16], i.e. (so_param >> 16) & 127; */
        LLVMValueRef so_vtx_count =
@@ -2319,12 +2306,22 @@ static void si_llvm_emit_streamout(struct si_shader_context *ctx,
                /* Compute (streamout_write_index + thread_id). */
                so_write_index = LLVMBuildAdd(builder, so_write_index, tid, "");
 
-               /* Compute the write offset for each enabled buffer. */
+               /* Load the descriptor and compute the write offset for each
+                * enabled buffer. */
                LLVMValueRef so_write_offset[4] = {};
+               LLVMValueRef so_buffers[4];
+               LLVMValueRef buf_ptr = LLVMGetParam(ctx->main_fn,
+                                                   SI_PARAM_RW_BUFFERS);
+
                for (i = 0; i < 4; i++) {
                        if (!so->stride[i])
                                continue;
 
+                       LLVMValueRef offset = lp_build_const_int32(gallivm,
+                                                                  SI_VS_STREAMOUT_BUF0 + i);
+
+                       so_buffers[i] = build_indexed_load_const(ctx, buf_ptr, offset);
+
                        LLVMValueRef so_offset = LLVMGetParam(ctx->main_fn,
                                                              ctx->param_streamout_offset[i]);
                        so_offset = LLVMBuildMul(builder, so_offset, LLVMConstInt(ctx->i32, 4, 0), "");