Mesa (master): nv50/ir: fix phi/ union sources when their def has been merged

[Ilia Mirkin]

Module: Mesa
Branch: master
Commit: dfb0ca16065c1d251101bb094f2cfd08cf3cda15
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=dfb0ca16065c1d251101bb094f2cfd08cf3cda15

Author: Ilia Mirkin <imirkin at alum.mit.edu>
Date:   Thu Jul 17 00:30:40 2014 -0400

nv50/ir: fix phi/union sources when their def has been merged

In a situation where double-register values are used, the phi nodes can
still end up being u32 values. They all get merged into one RA node
though. When fixing up the merge (which comes after the phi node), the
phi node's def would get fixed, but not its sources which would remain
at the low register value.

This maintains the invariant that a phi node's defs and sources are
allocated the same register.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>

---

 src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
index 242af4e..5ab6570 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_ra.cpp
@@ -1702,6 +1702,14 @@ GCRA::resolveSplitsAndMerges()
          Value *v = merge->getSrc(s);
          v->reg.data.id = regs.bytesToId(v, reg);
          v->join = v;
+         // If the value is defined by a phi/union node, we also need to
+         // perform the same fixup on that node's sources, since after RA
+         // their registers should be identical.
+         if (v->getInsn()->op == OP_PHI || v->getInsn()->op == OP_UNION) {
+            Instruction *phi = v->getInsn();
+            for (int phis = 0; phi->srcExists(phis); ++phis)
+               phi->getSrc(phis)->join = v;
+         }
          reg += v->reg.size;
       }
    }