[turbofan] Implement rounding of floats on x64 and ia32 without sse4.1.

src/x64/assembler-x64.cc

Index: src/x64/assembler-x64.cc
diff --git a/src/x64/assembler-x64.cc b/src/x64/assembler-x64.cc
index 3cf3398e876e3a51e291a2e2f60ca88355e8d87b..05c4d676418bbfb870460e852764e48220fd727b 100644
--- a/src/x64/assembler-x64.cc
+++ b/src/x64/assembler-x64.cc
@@ -3130,6 +3130,28 @@ void Assembler::cvttss2siq(Register dst, const Operand& src) {
   emit(0xF3);
   emit_rex_64(dst, src);
   emit(0x0F);
+  emit(0x2D);
+  emit_sse_operand(dst, src);
+}
+
+
+void Assembler::cvtss2siq(Register dst, XMMRegister src) {
+  DCHECK(!IsEnabled(AVX));
+  EnsureSpace ensure_space(this);
+  emit(0xF3);
+  emit_rex_64(dst, src);
+  emit(0x0F);
+  emit(0x2D);
+  emit_sse_operand(dst, src);
+}
+
+
+void Assembler::cvtss2siq(Register dst, const Operand& src) {
+  DCHECK(!IsEnabled(AVX));
+  EnsureSpace ensure_space(this);
+  emit(0xF3);
+  emit_rex_64(dst, src);
+  emit(0x0F);
   emit(0x2C);
   emit_sse_operand(dst, src);
 }
@@ -3310,6 +3332,17 @@ void Assembler::cvtsd2siq(Register dst, XMMRegister src) {
 }
 
 
+void Assembler::cvtsd2siq(Register dst, const Operand& src) {
+  DCHECK(!IsEnabled(AVX));
+  EnsureSpace ensure_space(this);
+  emit(0xF2);
+  emit_rex_64(dst, src);
+  emit(0x0F);
+  emit(0x2D);
+  emit_sse_operand(dst, src);
+}
+
+
 void Assembler::addsd(XMMRegister dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
   emit(0xF2);
@@ -3546,6 +3579,22 @@ void Assembler::roundsd(XMMRegister dst, XMMRegister src, RoundingMode mode) {
 }
 
 
+void Assembler::ldmxcsr(const Operand& dst) {
+  EnsureSpace ensure_space(this);
+  emit(0x0F);
+  emit(0xAE);
+  emit_operand(2, dst);
+}
+
+
+void Assembler::stmxcsr(const Operand& dst) {
+  EnsureSpace ensure_space(this);
+  emit(0x0F);
+  emit(0xAE);
+  emit_operand(3, dst);
+}
+
+
 void Assembler::movmskpd(Register dst, XMMRegister src) {
   EnsureSpace ensure_space(this);
   emit(0x66);