radeonsi: raise the alignment of LDS memory for compute shaders

This implies that the memory will always be at address 0, which allows
LLVM to generate slightly better code.

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 3617214..ed2db3d 100644 (file)
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -2217,7 +2217,7 @@ void si_declare_compute_memory(struct si_shader_context *ctx)
                                          LLVMArrayType(ctx->i8, lds_size),
                                          "compute_lds",
                                          AC_ADDR_SPACE_LDS);
-       LLVMSetAlignment(var, 4);
+       LLVMSetAlignment(var, 64 * 1024);
 
        ctx->ac.lds = LLVMBuildBitCast(ctx->ac.builder, var, i8p, "");
 }