commit 1a4f3ca8b04d9f2e42cdadc597559c242d003656
author Nicolas Geoffray <ngeoffray@google.com> Thu Jan 25 14:07:15 2018 +0000
committer Nicolas Geoffray <ngeoffray@google.com> Thu Jan 25 14:07:15 2018 +0000
tree 7e4affc0b98ab6006da335465c9ee184c820ef58
parent 4eb45631b38445c587c235f1b2fa1699ba820e76

Revert "ARM: Use r4 for stack overflow check to reduce code size."

Bug: 71627785
bug: 72428887

This reverts commit 4eb45631b38445c587c235f1b2fa1699ba820e76.

Change-Id: I601d78dbf1f9dafe8317e2db72831869a4092911

compiler/optimizing/code_generator_arm_vixl.cc

diff --git a/compiler/optimizing/code_generator_arm_vixl.cc b/compiler/optimizing/code_generator_arm_vixl.cc
index 6cbde72..577fe00 100644
--- a/compiler/optimizing/code_generator_arm_vixl.cc
+++ b/compiler/optimizing/code_generator_arm_vixl.cc
@@ -2490,12 +2490,8 @@
   }
 
   if (!skip_overflow_check) {
-    // Using r4 instead of IP saves 2 bytes. Start by asserting that r4 is available here.
-    for (vixl32::Register reg : kParameterCoreRegistersVIXL) {
-      DCHECK(!reg.Is(r4));
-    }
-    DCHECK(!kCoreCalleeSaves.Includes(r4));
-    vixl32::Register temp = r4;
+    UseScratchRegisterScope temps(GetVIXLAssembler());
+    vixl32::Register temp = temps.Acquire();
     __ Sub(temp, sp, Operand::From(GetStackOverflowReservedBytes(InstructionSet::kArm)));
     // The load must immediately precede RecordPcInfo.
     ExactAssemblyScope aas(GetVIXLAssembler(),