diff --git a/src/gallium/drivers/r300/compiler/radeon_optimize.c b/src/gallium/drivers/r300/compiler/radeon_optimize.c
index 4d2efd7b86d..14d8eb6bb4e 100644
--- a/src/gallium/drivers/r300/compiler/radeon_optimize.c
+++ b/src/gallium/drivers/r300/compiler/radeon_optimize.c
@@ -1030,6 +1030,14 @@ static void merge_channels(struct radeon_compiler * c, struct rc_instruction * i
 			cur->U.I.SaturateMode == inst->U.I.SaturateMode &&
 			(cur->U.I.DstReg.WriteMask & orig_dst_wmask) == 0) {
 
+			/* Skip the merge if one of the instructions writes just w channel
+			 * and we are compiling a fragment shader. We can pair-schedule it together
+			 * later anyway and it will also give the scheduler a bit more flexibility.
+			 */
+			if (c->has_omod && (cur->U.I.DstReg.WriteMask == RC_MASK_W ||
+				inst->U.I.DstReg.WriteMask == RC_MASK_W))
+				continue;
+
 			if (inst_combination(cur, inst, RC_OPCODE_MOV, RC_OPCODE_MOV)) {
 				if (merge_movs(c, inst, cur))
 					return;