broadcom/compiler: fix up copy propagation for v71

Update rules for unsafe copy propagations to match v7.x.

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/25450>

diff --git a/src/broadcom/compiler/vir_opt_copy_propagate.c b/src/broadcom/compiler/vir_opt_copy_propagate.c
index c4aa725..1260838 100644 (file)
--- a/src/broadcom/compiler/vir_opt_copy_propagate.c
+++ b/src/broadcom/compiler/vir_opt_copy_propagate.c
@@ -35,7 +35,7 @@
 #include "v3d_compiler.h"
 
 static bool
-is_copy_mov(struct qinst *inst)
+is_copy_mov(const struct v3d_device_info *devinfo, struct qinst *inst)
 {
         if (!inst)
                 return false;
@@ -62,36 +62,65 @@ is_copy_mov(struct qinst *inst)
                 return false;
         }
 
-        switch (inst->src[0].file) {
-        case QFILE_MAGIC:
-                /* No copy propagating from R3/R4/R5 -- the MOVs from those
-                 * are there to register allocate values produced into R3/4/5
-                 * to other regs (though hopefully r3/4/5).
-                 */
-                switch (inst->src[0].index) {
-                case V3D_QPU_WADDR_R3:
-                case V3D_QPU_WADDR_R4:
-                case V3D_QPU_WADDR_R5:
-                        return false;
+        if (devinfo->ver <= 42) {
+                switch (inst->src[0].file) {
+                case QFILE_MAGIC:
+                        /* No copy propagating from R3/R4/R5 -- the MOVs from
+                         * those are there to register allocate values produced
+                         * into R3/4/5 to other regs (though hopefully r3/4/5).
+                         */
+                        switch (inst->src[0].index) {
+                        case V3D_QPU_WADDR_R3:
+                        case V3D_QPU_WADDR_R4:
+                        case V3D_QPU_WADDR_R5:
+                                return false;
+                        default:
+                                break;
+                        }
+                        break;
+
+                case QFILE_REG:
+                        switch (inst->src[0].index) {
+                        case 0:
+                        case 1:
+                        case 2:
+                                /* MOVs from rf0/1/2 are only to track the live
+                                 * intervals for W/centroid W/Z.
+                                 */
+                                return false;
+                        }
+                        break;
+
                 default:
                         break;
                 }
-                break;
-
-        case QFILE_REG:
-                switch (inst->src[0].index) {
-                case 0:
-                case 1:
-                case 2:
-                        /* MOVs from rf0/1/2 are only to track the live
+        } else {
+                assert(devinfo->ver >= 71);
+                switch (inst->src[0].file) {
+                case QFILE_REG:
+                        switch (inst->src[0].index) {
+                        /* MOVs from rf1/2/3 are only to track the live
                          * intervals for W/centroid W/Z.
+                         *
+                         * Note: rf0 can be implicitly written by ldvary
+                         * (no temp involved), so it is not an SSA value and
+                         * could clash with writes to other temps that are
+                         * also allocated to rf0. In theory, that would mean
+                         * that we can't copy propagate from it, but we handle
+                         * this at register allocation time, preventing temps
+                         * from being allocated to rf0 while the rf0 value from
+                         * ldvary is still live.
                          */
-                        return false;
-                }
-                break;
+                        case 1:
+                        case 2:
+                        case 3:
+                                return false;
+                        }
+                        break;
 
-        default:
-                break;
+                default:
+                        break;
+                }
         }
 
         return true;
@@ -135,7 +164,7 @@ try_copy_prop(struct v3d_compile *c, struct qinst *inst, struct qinst **movs)
                  */
                 struct qinst *mov = movs[inst->src[i].index];
                 if (!mov) {
-                        if (!is_copy_mov(c->defs[inst->src[i].index]))
+                        if (!is_copy_mov(c->devinfo, c->defs[inst->src[i].index]))
                                 continue;
                         mov = c->defs[inst->src[i].index];
 
@@ -245,7 +274,7 @@ vir_opt_copy_propagate(struct v3d_compile *c)
 
                         apply_kills(c, movs, inst);
 
-                        if (is_copy_mov(inst))
+                        if (is_copy_mov(c->devinfo, inst))
                                 movs[inst->dst.index] = inst;
                 }
         }