From: Christoph Bumiller <e0425955@student.tuwien.ac.at>
Date: Sat, 7 Jan 2012 20:00:51 +0000 (+0100)
Subject: nv50/ir/ra: don't coalesce contraint-moves
X-Git-Tag: 062012170305~2292
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=4021979182d3a6eb2bed1e9d784e218eb88bfa28;p=profile%2Fivi%2Fmesa.git

nv50/ir/ra: don't coalesce contraint-moves

This could lead to incorrect code when fixed regs are involved.

Surprisingly, the increased freedom actually leads to lower
register usage in some cases. Still want to find a better way
to treat constraints though ...
---

diff --git a/src/gallium/drivers/nv50/codegen/nv50_ir_ra.cpp b/src/gallium/drivers/nv50/codegen/nv50_ir_ra.cpp
index ff6d966..f08026c 100644
--- a/src/gallium/drivers/nv50/codegen/nv50_ir_ra.cpp
+++ b/src/gallium/drivers/nv50/codegen/nv50_ir_ra.cpp
@@ -513,6 +513,10 @@ RegAlloc::coalesceValues(unsigned int mask)
       case OP_MOV:
          if (!(mask & JOIN_MASK_MOV))
             break;
+         i = insn->getDef(0)->uses ? insn->getDef(0)->uses->getInsn() : NULL;
+         // if this is a contraint-move there will only be a single use
+         if (i && i->op == OP_CONSTRAINT)
+            break;
          i = insn->getSrc(0)->getUniqueInsn();
          if (i && !i->constrainedDefs())
             insn->getDef(0)->coalesce(insn->getSrc(0), false);