diff --git a/src/amd/llvm/ac_llvm_build.c b/src/amd/llvm/ac_llvm_build.c
index 5ef1d28f58e..08960c2e046 100644
--- a/src/amd/llvm/ac_llvm_build.c
+++ b/src/amd/llvm/ac_llvm_build.c
@@ -2752,6 +2752,9 @@ LLVMValueRef ac_build_mbcnt_add(struct ac_llvm_context *ctx, LLVMValueRef mask,
    LLVMValueRef val;
 
    if (ctx->wave_size == 32) {
+      if (LLVMTypeOf(mask) == ctx->i64)
+         mask = LLVMBuildTrunc(ctx->builder, mask, ctx->i32, "");
+
       val = ac_build_intrinsic(ctx, "llvm.amdgcn.mbcnt.lo", ctx->i32,
                                (LLVMValueRef[]){mask, add}, 2, 0);
    } else {