SIMD cmpeq for x86/x86_64

Rationale:
Break-out CL of ART Vectorizer.
Enables fast all-ones optimization.

Bug: 34083438
Test: assembler_x86[_64]_test
Change-Id: I70bd71305f2ecc322ccada5471c197a578c0526e
diff --git a/compiler/utils/x86/assembler_x86.cc b/compiler/utils/x86/assembler_x86.cc
index 0a6ceef..5307dc0 100644
--- a/compiler/utils/x86/assembler_x86.cc
+++ b/compiler/utils/x86/assembler_x86.cc
@@ -1221,6 +1221,43 @@
 }
 
 
+void X86Assembler::pcmpeqb(XmmRegister dst, XmmRegister src) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0x66);
+  EmitUint8(0x0F);
+  EmitUint8(0x74);
+  EmitXmmRegisterOperand(dst, src);
+}
+
+
+void X86Assembler::pcmpeqw(XmmRegister dst, XmmRegister src) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0x66);
+  EmitUint8(0x0F);
+  EmitUint8(0x75);
+  EmitXmmRegisterOperand(dst, src);
+}
+
+
+void X86Assembler::pcmpeqd(XmmRegister dst, XmmRegister src) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0x66);
+  EmitUint8(0x0F);
+  EmitUint8(0x76);
+  EmitXmmRegisterOperand(dst, src);
+}
+
+
+void X86Assembler::pcmpeqq(XmmRegister dst, XmmRegister src) {
+  AssemblerBuffer::EnsureCapacity ensured(&buffer_);
+  EmitUint8(0x66);
+  EmitUint8(0x0F);
+  EmitUint8(0x38);
+  EmitUint8(0x29);
+  EmitXmmRegisterOperand(dst, src);
+}
+
+
 void X86Assembler::shufpd(XmmRegister dst, XmmRegister src, const Immediate& imm) {
   AssemblerBuffer::EnsureCapacity ensured(&buffer_);
   EmitUint8(0x66);