diff options
| -rw-r--r-- | src/mesa/drivers/dri/i965/brw_vec4_cmod_propagation.cpp | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_cmod_propagation.cpp b/src/mesa/drivers/dri/i965/brw_vec4_cmod_propagation.cpp index 0c8224f5f83..c376bebbe8e 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4_cmod_propagation.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4_cmod_propagation.cpp @@ -115,6 +115,18 @@ opt_cmod_propagation_local(bblock_t *block) break; } + /* The conditional mod of the CMP/CMPN instructions behaves + * specially because the flag output is not calculated from the + * result of the instruction, but the other way around, which + * means that even if the condmod to propagate and the condmod + * from the CMP instruction are the same they will in general give + * different results because they are evaluated based on different + * inputs. + */ + if (scan_inst->opcode == BRW_OPCODE_CMP || + scan_inst->opcode == BRW_OPCODE_CMPN) + break; + /* Otherwise, try propagating the conditional. */ enum brw_conditional_mod cond = inst->src[0].negate ? brw_swap_cmod(inst->conditional_mod) |