[Mesa-dev] [PATCH 2/6] nv50/ir: swap sources in PostRaConstantFolding when src0 is imm

[Karol Herbst]

From: Karol Herbst <git at karolherbst.de>

helps some shaders in multiple games

total instructions in shared programs : 1922267 -> 1922121 (-0.01%)
total gprs used in shared programs    : 251878 -> 251878 (0.00%)
total local used in shared programs   : 5673 -> 5673 (0.00%)
total bytes used in shared programs   : 17625496 -> 17624144 (-0.01%)

                local        gpr       inst      bytes
    helped           0           0          62          62
      hurt           0           0           0           0

Signed-off-by: Karol Herbst <nouveau at karolherbst.de>
---
 .../drivers/nouveau/codegen/nv50_ir_peephole.cpp   | 69 +++++++++++++---------
 1 file changed, 42 insertions(+), 27 deletions(-)

diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
index bfec130..9c60ea1 100644
--- a/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
+++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_peephole.cpp
@@ -2881,37 +2881,52 @@ NV50PostRaConstantFolding::visit(BasicBlock *bb)
          def = i->getSrc(1)->getInsn();
          if (def && def->op == OP_SPLIT && typeSizeof(def->sType) == 4)
             def = def->getSrc(0)->getInsn();
-         if (def && def->op == OP_MOV && def->src(0).getFile() == FILE_IMMEDIATE) {
-            vtmp = i->getSrc(1);
-            if (typeSizeof(i->sType) > 2) {
-               i->setSrc(1, def->getSrc(0));
-            } else {
-               ImmediateValue val;
-               bool ret = def->src(0).getImmediate(val);
-               assert(ret);
-               if (typeSizeof(i->sType) == 2) {
-                  if (i->getSrc(1)->reg.data.id & 1)
-                     val.reg.data.u32 >>= 16;
-                  val.reg.data.u32 &= 0xffff;
-               }
-               i->setSrc(1, new_ImmediateValue(bb->getProgram(), val.reg.data.u32));
-            }
+         if (!(def && def->op == OP_MOV && def->src(0).getFile() == FILE_IMMEDIATE)) {
+            /* maybe we can swap it */
+            def = i->getSrc(0)->getInsn();
+            if (def && def->op == OP_SPLIT && typeSizeof(def->sType) == 4)
+               def = def->getSrc(0)->getInsn();
+            if (!(def && def->op == OP_MOV && def->src(0).getFile() == FILE_IMMEDIATE))
+               break;
+
+            Value *tmpS = i->getSrc(0);
+            Modifier tmpM = i->src(0).mod;
+
+            i->setSrc(0, i->getSrc(1));
+            i->src(0).mod = i->src(1).mod;
 
-            /* There's no post-RA dead code elimination, so do it here
-             * XXX: if we add more code-removing post-RA passes, we might
-             *      want to create a post-RA dead-code elim pass */
-            if (post_ra_dead(vtmp->getInsn())) {
-               Value *src = vtmp->getInsn()->getSrc(0);
-               // Careful -- splits will have already been removed from the
-               // functions. Don't double-delete.
-               if (vtmp->getInsn()->bb)
-                  delete_Instruction(prog, vtmp->getInsn());
-               if (src->getInsn() && post_ra_dead(src->getInsn()))
-                  delete_Instruction(prog, src->getInsn());
+            i->setSrc(1, tmpS);
+            i->src(1).mod = tmpM;
+         }
+
+         vtmp = i->getSrc(1);
+         if (typeSizeof(i->sType) > 2) {
+            i->setSrc(1, def->getSrc(0));
+         } else {
+            ImmediateValue val;
+            bool ret = def->src(0).getImmediate(val);
+            assert(ret);
+            if (typeSizeof(i->sType) == 2) {
+               if (i->getSrc(1)->reg.data.id & 1)
+                  val.reg.data.u32 >>= 16;
+               val.reg.data.u32 &= 0xffff;
             }
+            i->setSrc(1, new_ImmediateValue(bb->getProgram(), val.reg.data.u32));
+         }
 
-            break;
+         /* There's no post-RA dead code elimination, so do it here
+          * XXX: if we add more code-removing post-RA passes, we might
+          *      want to create a post-RA dead-code elim pass */
+         if (post_ra_dead(vtmp->getInsn())) {
+            Value *src = vtmp->getInsn()->getSrc(0);
+            // Careful -- splits will have already been removed from the
+            // functions. Don't double-delete.
+            if (vtmp->getInsn()->bb)
+               delete_Instruction(prog, vtmp->getInsn());
+            if (src->getInsn() && post_ra_dead(src->getInsn()))
+               delete_Instruction(prog, src->getInsn());
          }
+
          break;
       default:
          break;
-- 
2.7.0