[ia32] Introduce BMI instructions.

src/ia32/macro-assembler-ia32.cc

Index: src/ia32/macro-assembler-ia32.cc
diff --git a/src/ia32/macro-assembler-ia32.cc b/src/ia32/macro-assembler-ia32.cc
index 1bd31b32ecd27e21ebf0b53a0a67b9ffe143d18a..f388abd3959a32c65a411f4ebd28a1d1d151a677 100644
--- a/src/ia32/macro-assembler-ia32.cc
+++ b/src/ia32/macro-assembler-ia32.cc
@@ -2450,7 +2450,11 @@ void MacroAssembler::Pinsrd(XMMRegister dst, const Operand& src, int8_t imm8) {
 
 
 void MacroAssembler::Lzcnt(Register dst, const Operand& src) {
-  // TODO(intel): Add support for LZCNT (with ABM/BMI1).
+  if (CpuFeatures::IsSupported(LZCNT)) {
+    CpuFeatureScope scope(this, LZCNT);
+    lzcnt(dst, src);
+    return;
+  }
   Label not_zero_src;
   bsr(dst, src);
   j(not_zero, &not_zero_src, Label::kNear);