[Mesa-dev] [PATCH 02/10] radeonsi: fix instanced arrays with non-zero start instance

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

Fixes piglit ARB_base_instance/arb_base_instance-drawarrays.

Cc: 10.3 10.4 <mesa-stable at lists.freedesktop.org>
---
 src/gallium/drivers/radeonsi/si_shader.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
index fb1419d..4b1279c 100644
--- a/src/gallium/drivers/radeonsi/si_shader.c
+++ b/src/gallium/drivers/radeonsi/si_shader.c
@@ -236,14 +236,14 @@ static LLVMValueRef get_instance_index_for_fetch(
 
 	LLVMValueRef result = LLVMGetParam(radeon_bld->main_fn,
 					   si_shader_ctx->param_instance_id);
-	result = LLVMBuildAdd(gallivm->builder, result, LLVMGetParam(
-			radeon_bld->main_fn, SI_PARAM_START_INSTANCE), "");
 
+	/* The division must be done before START_INSTANCE is added. */
 	if (divisor > 1)
 		result = LLVMBuildUDiv(gallivm->builder, result,
 				lp_build_const_int32(gallivm, divisor), "");
 
-	return result;
+	return LLVMBuildAdd(gallivm->builder, result, LLVMGetParam(
+			radeon_bld->main_fn, SI_PARAM_START_INSTANCE), "");
 }
 
 static void declare_input_vs(
-- 
2.1.0