commit 024aca2927f8ca76a5f1cfeaf749c065e5e2cbcd
author Christoffer Adamsen <christofferqa@google.com> Tue Jan 14 10:37:12 2025 +0100
committer Christoffer Adamsen <christofferqa@google.com> Tue Jan 14 01:48:53 2025 -0800
tree a9bfcdb9e942a662e6a1283057950d79b9b4e154
parent 2c19e8564d030f2977c8902523bd2ec805b53362

Account for unconstrained live intervals in allocateSingleInterval

Bug: b/389508413
Change-Id: If8929733b90c03083cb8ef3475429dfcb1922b0c

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 50b95a7..c48a408 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
@@ -1878,11 +1878,18 @@
       // of finding another candidate to spill via allocateBlockedRegister.
       assert unhandledInterval.hasUses();
       if (!unhandledInterval.getUses().first().hasConstraint()) {
-        int nextConstrainedPosition = unhandledInterval.firstUseWithConstraint(mode).getPosition();
-        int register = getSpillRegister(unhandledInterval, null);
-        LiveIntervals split = unhandledInterval.splitBefore(nextConstrainedPosition);
-        assignFreeRegisterToUnhandledInterval(unhandledInterval, register);
-        unhandled.add(split);
+        if (mode.hasRegisterConstraint(unhandledInterval)) {
+          int nextConstrainedPosition =
+              unhandledInterval.firstUseWithConstraint(mode).getPosition();
+          int register = getSpillRegister(unhandledInterval, null);
+          LiveIntervals split = unhandledInterval.splitBefore(nextConstrainedPosition);
+          assignFreeRegisterToUnhandledInterval(unhandledInterval, register);
+          unhandled.add(split);
+        } else {
+          assert unhandledInterval.firstUseWithConstraint(mode) == null;
+          int register = getSpillRegister(unhandledInterval, null);
+          assignFreeRegisterToUnhandledInterval(unhandledInterval, register);
+        }
       } else {
         allocateBlockedRegister(unhandledInterval);
       }