commit 8ebdce8a4f32e22b145beda4f62ff9d34bbfb334
author Mikaël Peltier <mikaelpeltier@google.com> Mon Jun 19 10:17:52 2017 +0200
committer Mikaël Peltier <mikaelpeltier@google.com> Mon Jun 19 10:17:52 2017 +0200
tree 97e8287cda48a34ff88bcc62e079f2a3c3a5798b
parent 9e261ba800ddc6f170b2f8b61d369aa49c4d9eda

Remove code that set use position of register

- It seems that this code can not change value already setted.

Change-Id: I5999c002bc01e2d105aa0cc4c3790d1e254112cc

src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java

diff --git a/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java b/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
index a317701..41759aa 100644
--- a/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
+++ b/src/main/java/com/android/tools/r8/ir/regalloc/LinearScanRegisterAllocator.java
@@ -1231,13 +1231,13 @@
 
     // Treat active linked argument intervals as pinned. They cannot be given another register
     // at their uses.
-    blockLinkedRegisters(
-        active, unhandledInterval, registerConstraint, usePositions, blockedPositions);
+    blockLinkedRegisters(active, unhandledInterval, registerConstraint, usePositions,
+        blockedPositions);
 
     // Treat inactive linked argument intervals as pinned. They cannot be given another register
     // at their uses.
-    blockLinkedRegisters(
-        inactive, unhandledInterval, registerConstraint, usePositions, blockedPositions);
+    blockLinkedRegisters(inactive, unhandledInterval, registerConstraint, usePositions,
+        blockedPositions);
 
     // Get the register (pair) that has the highest use position.
     boolean needsRegisterPair = unhandledInterval.requiredRegisters() == 2;
@@ -1456,16 +1456,12 @@
         if (register <= registerConstraint && other.overlaps(interval)) {
           for (int i = 0; i < other.requiredRegisters(); i++) {
             if (register + i <= registerConstraint) {
-              for (LiveIntervalsUse use : other.getUses()) {
-                if (use.getPosition() > interval.getStart()) {
-                  blockedPositions.set(
-                      register + i,
-                      Math.min(blockedPositions.get(register + i), use.getPosition()));
-                  usePositions.set(
-                      register + i,
-                      Math.min(usePositions.get(register + i), use.getPosition()));
-                }
-              }
+              blockedPositions.set(register + i,
+                  Math.min(blockedPositions.get(register + i),
+                      other.firstUseAfter(interval.getStart())));
+              // If we start blocking registers other than linked arguments, we might need to
+              // explicitly update the use positions as well as blocked positions.
+              assert usePositions.get(register + i) <= blockedPositions.get(register + i);
             }
           }
         }