freedreno/a3xx/compiler: fix for resolving PHI's

A value may be assigned on only one side of an if/else.  In this case we
can simply substitute a mov.f32f32.

Signed-off-by: Rob Clark <robclark@freedesktop.org>

diff --git a/src/gallium/drivers/freedreno/a3xx/ir3_flatten.c b/src/gallium/drivers/freedreno/a3xx/ir3_flatten.c
index 3cf76db5005fdaba3ececfc0be39a12887798d47..00a2bf1dc4753b7c442f751363db7a0a1f4fba99 100644 (file)
--- a/src/gallium/drivers/freedreno/a3xx/ir3_flatten.c
+++ b/src/gallium/drivers/freedreno/a3xx/ir3_flatten.c
@@ -51,7 +51,9 @@ static struct ir3_register *unwrap(struct ir3_register *reg)
                        switch (instr->opc) {
                        case OPC_META_OUTPUT:
                        case OPC_META_FLOW:
-                               return instr->regs[1];
+                               if (instr->regs_count > 1)
+                                       return instr->regs[1];
+                               return NULL;
                        default:
                                break;
                        }
@@ -78,25 +80,38 @@ static void ir3_instr_flatten(struct ir3_flatten_ctx *ctx,
                if (instr->opc == OPC_META_PHI) {
                        struct ir3_register *cond, *t, *f;
 
-                       /* convert the PHI instruction to sel.{f16,f32} */
-                       instr->category = 3;
+                       cond = unwrap(instr->regs[1]);
+                       t    = unwrap(instr->regs[2]);  /* true val */
+                       f    = unwrap(instr->regs[3]);  /* false val */
 
-                       /* instruction type based on dst size: */
-                       if (instr->regs[0]->flags & IR3_REG_HALF)
-                               instr->opc = OPC_SEL_F16;
-                       else
-                               instr->opc = OPC_SEL_F32;
-
-                       /* swap around src register order, to match what
-                        * hw expects:
+                       /* must have cond, but t or f may be null if only written
+                        * one one side of the if/else (in which case we can just
+                        * convert the PHI to a simple move).
                         */
-                       cond = instr->regs[1];
-                       t    = instr->regs[2];  /* true val */
-                       f    = instr->regs[3];  /* false val */
-
-                       instr->regs[1] = unwrap(f);
-                       instr->regs[2] = unwrap(cond);
-                       instr->regs[3] = unwrap(t);
+                       assert(cond);
+                       assert(t || f);
+
+                       if (t && f) {
+                               /* convert the PHI instruction to sel.{b16,b32} */
+                               instr->category = 3;
+
+                               /* instruction type based on dst size: */
+                               if (instr->regs[0]->flags & IR3_REG_HALF)
+                                       instr->opc = OPC_SEL_B16;
+                               else
+                                       instr->opc = OPC_SEL_B32;
+
+                               instr->regs[1] = t;
+                               instr->regs[2] = cond;
+                               instr->regs[3] = f;
+                       } else {
+                               /* convert to simple mov: */
+                               instr->category = 1;
+                               instr->cat1.dst_type = TYPE_F32;
+                               instr->cat1.src_type = TYPE_F32;
+                               instr->regs_count = 2;
+                               instr->regs[1] = t ? t : f;
+                       }
 
                        ctx->cnt++;
                } else if ((instr->opc == OPC_META_INPUT) &&