diff --git a/src/intel/compiler/brw_fs_nir.cpp b/src/intel/compiler/brw_fs_nir.cpp
index 0b609871d7e..f20912d4dba 100644
--- a/src/intel/compiler/brw_fs_nir.cpp
+++ b/src/intel/compiler/brw_fs_nir.cpp
@@ -1571,18 +1571,21 @@ fs_nir_emit_alu(nir_to_brw_state &ntb, nir_alu_instr *instr,
       assert(instr->def.bit_size == 32);
       assert(nir_src_bit_size(instr->src[0].src) == 32);
 
-      bld.FBH(retype(result, BRW_TYPE_UD), op[0]);
+      brw_reg tmp = bld.FBH(retype(op[0], BRW_TYPE_D));
 
       /* FBH counts from the MSB side, while GLSL's findMSB() wants the count
        * from the LSB side. If FBH didn't return an error (0xFFFFFFFF), then
        * subtract the result from 31 to convert the MSB count into an LSB
        * count.
        */
-      bld.CMP(bld.null_reg_d(), result, brw_imm_d(-1), BRW_CONDITIONAL_NZ);
+      brw_reg count_from_lsb = bld.ADD(negate(tmp), brw_imm_w(31));
 
-      inst = bld.ADD(result, result, brw_imm_d(31));
-      inst->predicate = BRW_PREDICATE_NORMAL;
-      inst->src[0].negate = true;
+      /* The high word of the FBH result will be 0xffff or 0x0000. After
+       * calculating 31 - fbh, we can obtain the correct result for
+       * ifind_msb(0) by ORing the (sign extended) upper word of the
+       * intermediate result.
+       */
+      bld.OR(result, count_from_lsb, subscript(tmp, BRW_TYPE_W, 1));
       break;
    }