Some assembler-level optimizations on ARM.

src/arm/macro-assembler-arm.cc

Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 1832db411a656f92aecfd53d4b7047dd90765e59..ab7643cce9b08cd575b8ab396963daebd9f6472f 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -2965,6 +2965,22 @@ void MacroAssembler::JumpIfNotBothSmi(Register reg1,
 }
 
 
+void MacroAssembler::UntagAndJumpIfSmi(
+    Register dst, Register src, Label* smi_case) {
+  STATIC_ASSERT(kSmiTag == 0);
+  mov(dst, Operand(src, ASR, kSmiTagSize), SetCC);
+  b(cc, smi_case);  // Shifter carry is not set for a smi.
+}
+
+
+void MacroAssembler::UntagAndJumpIfNotSmi(
+    Register dst, Register src, Label* smi_case) {

[ulan, 2012/01/27 15:24:35]

smi_case should be non_smi_case

+  STATIC_ASSERT(kSmiTag == 0);
+  mov(dst, Operand(src, ASR, kSmiTagSize), SetCC);
+  b(cs, smi_case);  // Shifter carry is set for a non-smi.
+}
+
+
 void MacroAssembler::JumpIfEitherSmi(Register reg1,
                                      Register reg2,
                                      Label* on_either_smi) {