Use unspilled virtual frames when compiling compare operations....

src/assembler-ia32.cc

Index: src/assembler-ia32.cc
===================================================================
--- src/assembler-ia32.cc	(revision 1019)
+++ src/assembler-ia32.cc	(working copy)
@@ -743,6 +743,21 @@
 }
 
 
+void Assembler::xchg(Register dst, Register src) {
+  EnsureSpace ensure_space(this);
+  last_pc_ = pc_;
+  if (src.is(eax) || dst.is(eax)) {  // Single-byte encoding
+    if (dst.is(eax)) {
+      dst = src;  // No need to copy eax to src, we assume src is eax.

[Kevin Millikin (Chromium), 2008/12/29 09:05:38]

More straightforward:
EMIT(0x90 | (dst.is(eax) ? src.code() : dst.code()));

[William Hesse, 2008/12/29 11:47:42]

Done.

+    }
+    EMIT(0x90 | dst.code());
+  } else {
+    EMIT(0x87);
+    EMIT(0xC0 | src.code() << 3 | dst.code());
+  }
+}
+
+
 void Assembler::adc(Register dst, int32_t imm32) {
   EnsureSpace ensure_space(this);
   last_pc_ = pc_;