commit 78441455a3f72014b8da68785197f0c88776f588
author Mike Klein <mtklein@google.com> Fri Nov 08 15:46:47 2019 -0600
committer Skia Commit-Bot <skia-commit-bot@chromium.org> Mon Nov 11 14:39:45 2019 +0000
tree 2ac1ce055701c1c618b1e7c48f7d8bc11d23cf55
parent 1edd468de3cacc0bc0f60aef4c2e5af16739bc8a

don't allocate an interpreter register for stores

Instructions only need a register if they've got an output.
This more closely mirrors what the JIT does.

Change-Id: I9cddba124a90c3afa698d82b1bb89808a7abd3c6
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/253762
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>

src/core/SkVM.cpp

diff --git a/src/core/SkVM.cpp b/src/core/SkVM.cpp
index 22abda0..fc17abe 100644
--- a/src/core/SkVM.cpp
+++ b/src/core/SkVM.cpp
@@ -1543,12 +1543,15 @@
             if (inst.y != inst.x                    ) { maybe_recycle_register(inst.y); }
             if (inst.z != inst.x && inst.z != inst.y) { maybe_recycle_register(inst.z); }
 
-            // Allocate a register if we have to, preferring to reuse anything available.
-            if (avail.empty()) {
-                reg[id] = fRegs++;
-            } else {
-                reg[id] = avail.back();
-                avail.pop_back();
+            // Instructions that die at themselves (stores) don't need a register.
+            if (inst.death != id) {
+                // Allocate a register if we have to, preferring to reuse anything available.
+                if (avail.empty()) {
+                    reg[id] = fRegs++;
+                } else {
+                    reg[id] = avail.back();
+                    avail.pop_back();
+                }
             }
         };