Module: Mesa
Branch: master
Commit: 5491458843998e8083baf9b62c14895946de1a3f
URL:
http://cgit.freedesktop.org/mesa/mesa/commit/?id=5491458843998e8083baf9b62c14895946de1a3f
Author: Ilia Mirkin <imir...@alum.mit.edu>
Date: Mon Jul 7 01:53:52 2014 -0400
nvc0/ir: remove merge/split pairs to allow normal propagation to occur
Because the TGSI interface creates merges for each instruction source
and then splits them back out, there are a lot of unnecessary
merge/split pairs which do essentially nothing. The various modifier/etc
propagation doesn't know how to walk though those, so just remove them
when they're unnecessary.
Signed-off-by: Ilia Mirkin <imir...@alum.mit.edu>
---
.../drivers/nouveau/codegen/nv50_ir_peephole.cpp | 30 ++++++++++++++++++++
1 file changed, 30 insertions(+)
diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
index 62d2ef7..6a4ea4e 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
@@ -118,6 +118,35 @@ CopyPropagation::visit(BasicBlock *bb)
//
=============================================================================
+class MergeSplits : public Pass
+{
+private:
+ virtual bool visit(BasicBlock *);
+};
+
+// For SPLIT / MERGE pairs that operate on the same registers, replace the
+// post-merge def with the SPLIT's source.
+bool
+MergeSplits::visit(BasicBlock *bb)
+{
+ Instruction *i, *next, *si;
+
+ for (i = bb->getEntry(); i; i = next) {
+ next = i->next;
+ if (i->op != OP_MERGE || typeSizeof(i->dType) != 8)
+ continue;
+ si = i->getSrc(0)->getInsn();
+ if (si->op != OP_SPLIT || si != i->getSrc(1)->getInsn())
+ continue;
+ i->def(0).replace(si->getSrc(0), false);
+ delete_Instruction(prog, i);
+ }
+
+ return true;
+}
+
+//
=============================================================================
+
class LoadPropagation : public Pass
{
private:
@@ -2662,6 +2691,7 @@ Program::optimizeSSA(int level)
{
RUN_PASS(1, DeadCodeElim, buryAll);
RUN_PASS(1, CopyPropagation, run);
+ RUN_PASS(1, MergeSplits, run);
RUN_PASS(2, GlobalCSE, run);
RUN_PASS(1, LocalCSE, run);
RUN_PASS(2, AlgebraicOpt, run);
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